Ophthalmology Syllabus

Faculty of Medicine - MTI University

Academic Year 2023/2024
List of Contents:
1- Eyelids……………………………..2
2- Conjunctiva………………………12
3- Cornea…………………………….25
4- Sclera………………………………47
5- Lacrimal System…………………51
6- Dry Eye…………………………….57
7- Lens………………………………..61
8- Uvea………………………………..75
9- Glaucoma…………………………88
10-Retina……………………………..111
11- Orbit……………………………..137
12-Errors of Refraction……………159
13-Squint……………………………..173
14-Trauma……………………………184
15-Tumors……………………………198
16-Optic Nerve……………………….203
17-Neuro-Ophthalmology………….211

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 Eyelids

Anatomy of the Eyelids:

• The two eyelids are protective for the globe (mainly through reflex
blinking) and are responsible for the normal homogenous distribution
of the tear film over the cornea. Furthermore, some of the eyelid
structures are responsible for tear film production.
• The upper eyelid usually covers the upper one-fifth of the cornea
(about 2 mm).
• The lower eyelid usually touches the limbus.
• Each eyelid is formed of anterior and posterior lamellae, separated by
the submuscular plane (surgical landmark).
• Anterior lamella is formed of skin and fibers of the Orbicularis Oculi
muscle.
• Posterior lamella is formed of tarsus (containing the meibomian glands
and continues superiorly with the orbital septum) and the palpebral
conjunctiva.
• The meibomian glands are responsible for secreting the oily layer of
the tear film (outermost layer of the tear film).
• The orbital septum separates the eyelid tissues from the orbital tissues.
• The lid margin contains two anatomical landmarks:
❖ Grey line: through which the submuscular plane is reached.
❖ White line: through which the meibomian glands are reached, and the
orifices of the glands open through it on the lid margin.

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Diseases of the Eyelids:

• Lid Abscess
• Lid Glands Diseases
Stye (Hordeolum Externum)
Chalazion
Infected Chalazion (Hordeolum Internum)
• Blepharitis
Seborrheic
Ulcerative
Parasitic
Angular
• Lashes Anomalies
Distichiasis
Trichiasis
• Lid Margin Malpositions
Entropion
Ectropion
Ptosis
Lid retraction

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1- Lid Abscess
• Acute suppurative infection within the lid tissues.
• Treatment is with hot fomentations and systemic antibiotics.
• If the abscess persists or if there is pus pointing, a surgical
incision is performed (horizontal rather than vertical incision to
avoid scarring and cicatricial ectropion).

2- Lid Glands Diseases

Stye (Hordeolum Externum)
• Acute suppurative infection of the sebaceous glands at
the roots (follicles) of eyelashes.
• Presents as a painful swelling that starts diffuse then
becomes localized (with pus pointing) and is usually
related to the root of an eyelash.
• Treatment for the diffuse stage is by hot fomentations
and systemic antibiotics (if needed), and treatment for
the localized stage is by epilation of the diseased lash
from its root.
• Multiple recurrent styes may indicate systemic diseases
(mainly diabetes mellitus) or local eye troubles (as
uncorrected errors of refraction or ulcerative “staph”
blepharitis).

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Chalazion
• Chronic lipo granulomatous inflammation of the
meibomian glands.
• Presents as a painless eyelid swelling.
• If large, may cause mechanical ptosis of the upper eyelid
or mechanical ectropion of the lower eyelid.
• Chalazions can cause compression on the corneal
surface, resulting in corneal astigmatism (with blurred
vision).
• It usually resolves spontaneously, but if persistent,
intralesional steroids are injected, or surgical incision
and curettage from inside are performed.
• Recurrent chalazion at the same location may be a
warning sign of a sebaceous adenocarcinoma of the
meibomian glands of the eyelid tarsus (excisional biopsy
is needed).

Infected Chalazion (Hordeolum Internum)

• If an acute infection occurs on top of a chalazion.
• Differentiated from the diffuse stage of stye by:
❖ Its posterior location.
❖ More obviously seen from the conjunctival side.
❖ Decreases by forcible lid closure, as it lies
posterior to the orbicularis oculi muscle, so its
contraction decreases its size (on the contrary to
the diffuse stye that remains of the same size on
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 lid closure, as it lies in front of the orbicularis oculi
muscle, so the muscle contraction does not affect
its size).
• Treatment is by hot fomentations and systemic
antibiotics till the acute stage subsides, followed by
incision and curettage of the chalazion.

• Blepharitis (Lid Margin Inflammations)

Seborrheic (Scaly) Blepharitis
• Abnormal meibomian glands secretions on the lid
margin.
• May be associated with scalp seborrhea.
• Presents as dry scales or greasy oily secretions on the
lid margins and eyelashes.
• On the trial of scale removal, the lid margin appears
hyperemic, yet no ulcerations of the margin occur with
removal.
• Treated by massaging the lid after warm compresses,
local scrubs or systemic anti-seborrheic treatments are
added according to the severity of the condition.

Ulcerative Blepharitis
• Acute suppurative infection (by staph aureus) of the lid
margin.

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 • Presents as yellow crusts or glued lash roots with
yellowish secretions.
• On trial of removing the crusts, the lid margin is both
hyperemic and ulcerated.
• Complications of recurrent attacks:
❖ Hypersensitivity reaction: Phlycten (which is
a type IV hypersensitivity and can also be
caused by TB infection or parasitic
infestations by ascaris or ancylostomiases).
❖ Spread of infection causing marginal keratitis
or styes.
❖ Eyelashes fibrosis at the roots causing
trichiasis.
❖ Lid margin fibrosis and irregularities with
thickening (tylosis).
❖ Lost lashes (madarosis).
• Treatment is with antibiotic ointment application on the
lid margin with frequent local lid scrubs and proper
hygiene.

Parasitic Blepharitis
• Caused by pthirus pubis (pubic louse) if it reaches the lid
margin (through rubbing the eyes with fingers that are
contaminated from the pubic area).
• Causes severe itching, and the lice or their nits (eggs)
are seen on the lashes and the lash roots.
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 • Treated by cutting the lashes and local anti-parasitic
ointments (containing acetic acid and mercuric oxide).

Angular Blepharitis
• Caused by Morax Axenfield diplobacillus which infects
the lateral canthal skin (more dry area away from the
lacrimal system), releasing proteolytic enzymes causing
skin macerations.
• Can spread causing marginal keratitis or conjunctivitis.
• Treated by topical antibiotics with zinc to neutralize the
proteolytic enzymes of the bacteria.

• Lashes Anomalies
Distichiasis
• An abnormal extra row of lashes arising from the meibomian
gland orifices.
• Can rub against the cornea causing corneal epithelial
damage, so it is treated by surgical splitting of the lid at the
grey line and cryo application to destroy the extra lashes.

Trichiasis
• The lashes arise from their normal origin but are
abnormally directed, so they rub against the
cornea.
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 • Main causes are trachoma and recurrent
ulcerative blepharitis.

• Causes foreign body sensation, reflex lacrimation,

and photophobia. Punctate epithelial erosions with
consequent infectious keratitis can develop from
continuously rubbing the lashes against the
cornea.

• Treated by permanent destruction by LASER or

electrolysis.

• Lid Margin Malposition

Entropion (Entropion Trichiasis)
• Inward rolling of the lid margin.
• Causes: involutional, congenital, and cicatricial “trachoma”.
• Results in rubbing of the lashes against the corneal epithelium
(entropion trichiasis), with reflex lacrimation and photophobia,
and foreign body sensation. Furthermore, punctate epithelial
erosions and possible corneal ulcers are possible
complications.
• Treated by surgical correction of the lid margin position.

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Ectropion
• Outward rolling of the lid margin, where the lower
punctum is obvious without lid eversion, and the
palpebral conjunctiva is seen in severe conditions.
• Causes: involutional, congenital, cicatricial “face scars”,
mechanical “lower lid masses as chalazion”, and
paralytic “facial palsy with orbicularis oculi paralysis”.
• Results in exposure keratopathy, and also improper
apposition of the lid margin against the globe, so there is
no proper function of the tear drainage system, resulting
in improper tear drainage (epiphora).
• D.D.: In entropion, there is reflex lacrimation from
corneal irritation rather than epiphora from improper
drainage in cases of ectropion.

Ptosis
• Drooping of the upper eyelid below the normal position.
• Causes: involutional, congenital, neurogenic
“oculomotor palsy- horner’s syndrome- myasthenia
gravis”, and mechanical “upper lid masses as
chalazion”.
• Ptosis is evaluated by margin reflex distance (normally 4
mm), palpebral fissure height (normally 10 mm), and
levator function (thumb test, normally more than 10 mm).
• The major problem in ptosis is amblyopia (if neglected),
where the continuous anatomical defect causes sensory
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 deprivation of the visual stimulus, causing a functional
impairment of vision that persists even after full
correction of the anatomical problem.
• The possibility of amblyopia develops during the critical
period (from 6-8 months to 6-9 years), that is why
surgical interference for correcting significant ptosis is
done early if the patient is in the critical period.
• Treatment of ptosis is done by surgical intervention,
where levator resection surgery is done for mild cases
and frontalis sling surgery is mainly for severe cases.
• Surgical intervention is usually done at preschool age to
avoid social embarrassment, but it is done as early as
possible if there is severe ptosis in the critical period
(where severe ptosis is diagnosed by drooping of the
upper eyelid to hide the corneal light reflex i.e., margin
reflex distance is zero).

Lid Retraction
• The upper eyelid is receded upwards (causing a scleral
show) above the normal position.
• The most common cause in adults is thyroid
ophthalmopathy (which must be excluded in such a
condition).

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 Conjunctiva

Anatomy of the Conjunctiva:

• The conjunctiva is a transparent, vascular tissue that lines the eyelids

(palpebral conjunctiva) and covers the sclera (bulbar conjunctiva). It
should never invade the cornea.
• The conjunctival vessels are affected (conjunctival injection) in the
superficial inflammations (conjunctivitis), while the ciliary vessels
(ciliary injection) are affected in the intraocular inflammations
(keratitis, scleritis, uveitis, …etc.).
• The adenoid layer of the conjunctival tissue is not formed until the
third month of life, that is why there is no follicular reaction occurring
in the conjunctival tissue before the fourth month of the infant’s life.
• The conjunctival tissue contains the accessory lacrimal glands of
Krause and Wolfring (forming the aqueous portion of the tear film) and
also contains the goblet cells (forming the mucin layer of the tear film).
That is why conjunctivitis or conjunctival damage affects the tear film
composition.

Diseases of the Conjunctiva:

Ophthalmia Neonatorum
Clinical Features of Conjunctivitis
Complications of Conjunctivitis

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Infective Conjunctivitis (mainly bacterial, viral,
Chlamydial)
Chlamydia Trachomatis (Egyptian Ophthalmia)
Non-infective conjunctivitis (mainly allergic “Vernal
Keratoconjunctivitis and Phlyctenular
Keratoconjunctivitis”)
Miscellaneous Conjunctival Lesions (Pinguecula,
Pterygium, and Symblepharon)

Ophthalmia Neonatorum
• It refers to any conjunctivitis that occurs within the first month
of a newborn’s life.
• It is most commonly infective in origin, and the most common
infectious organisms are chlamydia trachomatis D-K (chlamydia
oculogenitalis), Neisseria gonorrhea, and herpes simplex type II.
These infections are transmitted to the newborn’s eyes through
infected maternal passages during vaginal delivery.
• Few cases of ophthalmia neonatorum are non-infective in
origin, where it is due to an allergic reaction to the preservatives
in topical eye drops if they are frequently instilled in the
newborn’s eyes.

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 • Ophthalmia neonatorum presents with conjunctival injection
and ocular discharge, which may be severe and purulent with
chlamydia trachomatis and Neisseria gonorrhea. Furthermore,
Neisseria gonorrhea can penetrate through intact corneal
epithelium causing infective keratitis together with the severe
form of conjunctivitis.
• On conjunctival examination under the slit lamp, there is a
papillary conjunctival reaction evident in the palpebral
conjunctiva.
• In ophthalmia neonatorum, the adenoid layer of the conjunctiva
is not yet formed, so there is no follicular conjunctival reaction,
and only papillae can be detected.
• Prophylaxis against ophthalmia neonatorum starts with proper
hygiene and cleanliness of the maternal passages before
delivery. If infection occurs, proper topical (and sometimes
systemic) antibiotics should be used together with frequent eye
wash with warm water.

Clinical Features of Conjunctivitis

1- Symptoms:
• Discomfort and foreign body sensation.
• Eye redness from conjunctival injection.
• Itching with allergic conjunctivitis.
• Discharge with infective conjunctivitis.

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2- Signs:
• Conjunctival injection (differentiated from ciliary injection by
the distribution of the vascular affection, where the conjunctival
injection is maximal in the fornices then it fades away towards
the limbus till it stops at the peri limbic area, on the contrary to
ciliary injection which involves the anterior ciliary vessels in the
peri limbic 1-2 mm area and also extends to affect the
conjunctival vessels through the existent anastomotic
channels).
• Discharge with conjunctivitis varies according to the cause,
where it is watery with viral, mucoid with allergic, mucopurulent
with bacterial, and purulent with virulent bacterial
conjunctivitis.
• Follicular conjunctival reaction (at the adenoid layer), which
represents an aggregation of lymphocytes, and appears as pale
yellowish-white elevations resembling the grains of rice. The
main causes of follicles are viral and chlamydial infections.
• Papillary conjunctival reaction, which represents epithelial
proliferations with a vascular connective tissue core and central
vessels, and appears as elevated red bumps with a central
vascular core. The main causes of papillae are bacterial and
chlamydial infections together with allergic conjunctivitis and
giant papillary reaction to contact lens use.
• Other associated signs with some types of conjunctivitis include
fever and preauricular lymph nodes in some cases of viral
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 conjunctivitis, and periocular vesicles with herpetic viral
conjunctivitis.

Complications of Conjunctivitis
1- Corneal Ulcers:
• Vary according to the type of conjunctivitis.
• Bacterial ulcers can occur with virulent bacterial conjunctival
pathogens that can invade an intact corneal epithelium
(Neisseria, Diphtheria, Listeria, and Hemophilus). Other
bacteria can cause ulcers only if the epithelium is denuded.
• Punctate epithelial erosions and secondary ulcers can occur
with viral conjunctivitis (as adenoviral infections).
• Dendritic corneal ulcers with herpes simplex infections.
• Shield ulcers with allergic conjunctivitis due to the spread of
the allergic reaction to the corneal epithelium.
2- Conjunctival Scarring:
• Common with chlamydial conjunctivitis (trachoma).
• Scarring of the palpebral conjunctiva causes trichiasis and
entropion trichiasis.
• Scarring also affects the goblet cells and the accessory
lacrimal glands causing dry eye symptoms.

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 Treatment of Infective Conjunctivitis
• Bacterial conjunctivitis is usually treated by frequent wash of
the discharge with warm water and topical antibiotic drops
during the day and ointment at night. Never bandage an eye
with discharge to avoid the flourishing of the infection.
• Viral conjunctivitis is usually self-limiting and requires
symptomatic treatment if needed (topical non-steroidal drops).
Dendritic ulcers complicating herpes conjunctivitis are treated
with acyclovir ointment.
• Chlamydial conjunctivitis (trachoma) is treated with systemic
azithromycin antibiotic +/- topical tetracyclines.

Chlamydia Trachomatis (Egyptian Ophthalmia)

• It is a chronic infectious keratoconjunctivitis caused by chlamydia
trachomatis A-C (a parasitic bacteria that grows intracellularly within
the epithelium “superficial infection” and stains with gGiemsastain as
intracytoplasmic basophilic inclusion bodies).
• It is the most common cause of preventable blindness in Egypt due to
its endemic nature in underprivileged areas.
• The organism is transmitted through flies that breed in feces and feed
on the discharge on the eyes and dirty clothes of unclean children in
such suburban areas. The spread of infection occurs to the whole
family members easily with the lack of proper hygienic measures.

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• Symptoms include ocular irritation, burning, and foreign body
sensation. Also, ocular redness and ocular discharge are common
symptoms.
• Signs of chlamydial kerato-conjunctivitis:
❖ Conjunctival injection.
❖ Mucopurulent discharge.
❖ Conjunctival follicles and papillae, which occur on both
palpebral and bulbar conjunctiva.
❖ Signs of healing and fibrosis: Trachoma is commonly associated
with fibrotic conjunctival reactions on healing, including:
✓ Arlet’s line: seen on the peripheral region of the palpebral
conjunctiva (near the lid margin).
✓ Post-trachomatous degenerations (PTDs), which are
fibrotic and necrotic debris and mucous aggregations.
✓ Post-trachomatous concretions (PTCs), which are
calcified PTDs.
✓ Diffuse fibrosis of the whole palpebral conjunctiva.
❖ With the above signs of healing and fibrosis, there are negative
conjunctival swabs and no active infection is detected.
❖ Corneal signs of trachoma:
✓ Herbert’s rosettes (limbal follicles).
✓ Active corneal pannus (superficial “subepithelial” corneal
infiltration and vascularization).
✓ Signs of old, healed corneal infection (Herbert’s pits and
healed corneal pannus).
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 N.B. Due to the recurrent nature of chlamydia trachomatis, it is
common to see signs of activity (mainly discharge, follicles,
papillae, or active corneal pannus) together with signs of old
infections (mainly conjunctival scarring, Herbert’s pits, or healed
corneal pannus).
• Complications of trachomatous infections:
❖ Conjunctival scarring can cause trichiasis and entropion
trichiasis with lashes rubbing against the corneal epithelium
causing punctate erosions and possible corneal ulcers.
❖ Conjunctival scarring can destroy goblet cells and accessory
lacrimal glands causing dry eye symptoms.
❖ Obstruction of the lacrimal puncta by fibrosis can cause
epiphora.
• Treatment of trachomatous infections: systemic azithromycin (+/-
topical tetracyclines) and surgical intervention to manage complications
of scarring (after healing) if needed.
• N.B. The WHO launched the “SAFE Strategy” for controlling the endemic
disease in Egypt. It includes: Surgical intervention for complications of
scarring, Antibiotic treatment with azithromycin, Facial cleanliness, and
Environmental sanitation.

Non-infective “Allergic” Conjunctivitis

1- Vernal Keratoconjunctivitis “Spring Catarrh”
• Bilateral, recurrent, seasonal allergic keratoconjunctivitis.
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• It is a type I hypersensitivity (atopy, IgE-mediated immune
response with histamine release from mast cells and
eosinophils) to exogenous allergens (mainly dust and
pollens).
• It is more common in boys (usually aged 5 to 15 years) and
has a hereditary element.
• It causes keratoconjunctivitis:
❖ Vernal conjunctivitis:
o Palpebral conjunctival affection: giant
(cobblestone) palpebral conjunctival papillae
that may induce mechanical ptosis.
o Bulbar conjunctival affection: gelatinous
masses of allergic reactions and mucous
aggregations with overlying Tranta dots (white
concretions representing eosinophils
aggregates and epithelial debris).
❖ Vernal Keratitis:
o Allergic pannus.
o Punctate epithelial erosions (micro erosions) or
shield ulcers (macro erosions) resulting from
the spread of the hypersensitivity reaction to
cause loss of the corneal epithelium.
• Treatment of spring catarrh:
❖ Topical antihistamines, non-steroidal, or steroids in
severe conditions.
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 ❖ Intralesional steroids (supratarsal injections) are
sometimes needed for resistant cases or to avoid the
complications of frequent topical steroids (mainly
elevated intraocular pressure).
❖ Mast cell stabilizers (disodium cromoglycate) and
antihistamines are prescribed in between the attacks
as a prophylactic treatment.
• N.B. Frequent eye rubbing with allergic conjunctivitis
commonly predisposes to keratoconus (due to disruption of
the collagen cross-links between the stromal collagen
lamellae of the cornea).

2- Phlyctenular Keratoconjunctivitis
• It is a delayed hypersensitivity reaction (type IV) to
endogenous antigens (mainly chronic staph blepharitis, TB,
or parasitic intestinal infestations with Ascaris or
ancylostomiases).
• It causes keratoconjunctivitis:
❖ Phlyctenular Conjunctivitis:
✓ It presents as a non-tender limbal or perilimbal
gelatinous nodule with an invading leash of blood
vessels.
❖ Phlyctenular Keratitis:

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 ✓ The limbal phlycten may invade the cornea causing
corneal phlycten and pannus formation.
• Treatment includes eradication of the endogenous antigen
(the infection causing the hypersensitivity reaction) and
using topical non-steroidal or steroids.
• N.B. The limbal phlycten resembles a case of nodular
episcleritis, but the latter presents at an older age (middle
age), usually in females with autoimmune diseases, and it is
a tender nodule that is fixed to the sclera (compared to the
phlycten which is a non-tender mobile nodule).

Miscellaneous Conjunctival Lesions

1- Pinguecula:
• A conjunctival degeneration occurring with chronic
ultraviolet exposure.
• It presents as a yellowish, non-tender, limbal, or perilimbal
nodule. It is innocuous and requires no treatment.

2- Pterygium:
• It is a conjunctival reaction to chronic exposure to ultraviolet
rays that usually occurs in people living in sunny areas. It is
commonly associated with limbal stem cell deficiency that

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 permits creeping of the conjunctival reactive ingrowth over
the cornea.
• It presents as a medial, triangular, fibrovascular conjunctival
ingrowth that encroaches over the cornea.
• Patients complain of cosmetic disfigurement, ocular redness
and irritation, and/or blurred vision.
• The causes of blurred vision with pterygium include:
❖ Irregular corneal astigmatism due to corresponding
fibrosis and flattening of the region of the cornea
affected by the ingrowth.
❖ Encroachment of the pterygium over the pupillary
area blocking the visual sensory input.
• Treatment includes surgical excision with a conjunctival
autograft “harvesting stem cells” (if it is a symptomatic
pterygium).

3- Symblepharon:
• It represents adhesions between the palpebral and the
bulbar conjunctiva.
• This causes cosmetic disfigurement, diplopia (due to limited
ocular motility in the opposite direction of the symblepharon
site), or dropped vision from its encroachment over the
cornea.

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• It is caused by conjunctival scarring (mainly caused by severe
attacks of trachoma or chemical burns).
• Treatment is by passing a glass rod containing steroids or
using a scleral shell. Surgical intervention is indicated in
severe conditions.

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 Cornea

Anatomy of the Cornea:

• It is a transparent, avascular tissue that constitutes the

anterior one-fifth of the outer coat of the globe.
• It is continuous posteriorly with the opaque sclera, where
the junction between the cornea and sclera is known as the
limbus or the corneoscleral junction).
• The limbus contains stem cells that are responsible for the
regeneration of the corneal epithelium.
• The anterior corneal surface is covered with tear film,
which is important for proper oxygenation, nutrition, and
providence of local immunity (lysozymes and lactoferrins)
to the superficial corneal layers (namely the epithelium and
superficial stroma).
• The posterior corneal surface is in contact with the
aqueous humor, which provides nutrition for the posterior
corneal layers.
• The anterior ciliary vessels (at the limbic area) supply the
main large macromolecules to the corneal tissue, but
without penetrating the corneal structure.
• The corneal thickness increases from center to periphery,
where the central cornea has an average thickness of 520-
530 um that reaches up to 1 mm at the limbus.

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• The corneal steepness decreases from the center to the
periphery, where the steepest corneal part is the central
part.
• The cornea is aspheric in shape, having a vertical diameter
of 10.6 mm and a horizontal diameter of 11.7 mm (in
adults), which creates a mild physiological astigmatism of
0.25-0.5 diopters (compensated by the lens optics).
• Functions of the cornea:
❖ It is the major ocular refractive surface (providing 42-
43 dioptric power “D”), which is vital for proper
refraction of the light rays to fall on the retina (to be
in focus).
❖ A protective function is provided by the richly
innervated corneal surface (subepithelial plexus of
long ciliary nerve endings) which renders the cornea
highly sensitive to protect against irritants (whether
intraocular or extraocular) through sending pain
signals.
❖ Histologically, the cornea is comprised of six distinct
layers:
1- Corneal epithelium:
✓ Stratified squamous non-keratinized.
✓ Can fully regenerate (without scarring) from
the limbal stem cells.
✓ It plays a role in preventing corneal edema,
where the tight junctions between the cells

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 prevent the influx of tear film into the stromal
tissue.
2- Bowman’s layer:
✓ It is an anterior condensation of the corneal
stroma.
✓ It is formed of collagen lamellae with
keratocytes and mucopolysaccharides in
between.
✓ When the keratocytes are injured (by
infectious or non-infectious agents), they
gain fibroblastic activity and cause scarring
of the corneal stroma.
3- Corneal stroma proper:
✓ It is formed of regular collagen lamellae
with the same structure as the Bowman’s
layer, and also corneal scarring is the fate
of stromal injury.
4- Dua’s layer:
✓ It is a newly identified posterior stromal
layer.
✓ It is formed of homogenously packed
stromal lamellae.
✓ It has clinical applications in lamellar
keratoplasties.
5- Descemet’s membrane:

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 ✓ It is the basement membrane of the corneal
endothelium.
✓ It is an elastic layer with high tensile
strength.
✓ It can fully regenerate from the underlying
corneal endothelium upon injury.
6- Corneal endothelium:
✓ It is a single layer of hexagonal cells.
✓ It cannot regenerate upon injury, but the
adjacent cells to the injured ones undergo
pleomorphism and polymegathism to cover
the defective site.
✓ This layer plays a major role in preventing
corneal edema, where an active Na-K pump
action that occurs in the endothelium can
pump out any aqueous that enters the
corneal stromal tissue.

Diseases of the Cornea:

Keratitis:
✓ Infective (bacterial, viral, fungal,
acanthamoeba)
✓ Non-infective
Corneal degenerations:
✓ Arcus senilis
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 ✓ Band keratopathy
Keratoconus (Corneal ectasia)

Keratitis

• It is an inflammation of the corneal stroma (whether

infectious or non-infectious).
• Infectious keratitis includes bacterial, viral, fungal, and
acanthamoeba keratitis.
• Non-infectious keratitis includes traumatic and
autoimmune causes.
• If keratitis is associated with a corneal epithelial defect, it is
known as a corneal ulcer, whereas if there is an epithelial
defect without stromal inflammation, this is known as
corneal abrasion (or erosion) rather than a corneal ulcer.

Infective Bacterial Keratitis:

• Bacteria can invade the corneal stroma only after the
existence of an epithelial defect (except Neisseria,
Diphtheria, Listeria, and Hemophilus which can penetrate
an intact epithelium).
• Once the bacteria reach the corneal stroma, they nourish
on the stromal tissue and flourish there (the stroma is a
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 good culture medium for the organisms), with further
deeper penetration that may end in corneal perforation if
not properly treated.
• Predisposing factors for corneal ulcers:
❖ Trauma (Trachoma with rubbing lashes, improper
contact lens wear and poor fitting, and fingernail
abrasions).
❖ Dry eye (tear film is vital for epithelial nourishing).
❖ Diminished corneal sensation (recurrent herpes,
recurrent attacks of trigeminal neuralgia, and abuse
of topical anesthetics), as corneal nerve endings
release neurotrophic factors that are important for
epithelial integrity.
❖ Existence of a chronic nidus of infection
(dacryocystitis, conjunctivitis, blepharitis) which can
compromise the viability of the tear film, so the
corneal epithelium becomes devitalized.

• Clinical picture of bacterial corneal ulcer:

❖ Symptoms:
✓ It is one of the important causes of painful red eyes
and painful drop of vision.
✓ Pain is stitching or pricking in nature "like a needle"
due to irritation of the exposed subepithelial long

30
 ciliary nerve endings. Their irritation causes reflex
lacrimation, photophobia, and blepharospasm.
✓ Ocular redness.
✓ Drop of vision which is mainly due to its central or
paracentral location.
❖ Signs:
✓ Tenderness.
✓ Ciliary injection (peri limbic and extends to the
conjunctival vessels through anastomotic channels).
✓ Affected visual acuity.
✓ Slit lamp findings:
▪ Positive fluorescein 1% staining (green glow with
cobalt blue light). It is a staining of the corneal stroma
if the epithelium is denuded (lost).
▪ Stromal infiltration (greyish-white corneal opacity,
mainly central or paracentral), with surrounding
stromal edema due to the ongoing inflammatory
response.

• Complications of bacterial corneal ulcer:

✓ Descemetocele: If the stromal invasion progresses,
it reaches the Descemet’s membrane, which is
resistant to bacterial invasion. It then bulges under
even normal intraocular pressure forming a clear
vesicle at the ulcer base, which is a warning sign of
impending perforation.

31
✓ Corneal perforation: it manifests as a sudden onset
of sharp ocular pain, followed by a gush of a small
amount of warm fluid (aqueous humor) and relief of
pain (upon perforation as the pressure gives way).
The perforation site can be seen on slit lamp
examination, with iris prolapse from the perforation
site if it is paracentral or peripheral. The intraocular
pressure becomes soft, and the anterior chamber is
shallow or lost.
✓ Hypopyon: it means the presence of pus in the
anterior chamber. This pus is usually sterile (does not
contain an organism unless perforation occurs). It is
an aggregation of neutrophils in the anterior chamber
because of toxic iritis with virulent bacterial ulcers
(where the organism releases its toxins that can
percolate through intact Descemet’s membrane and
endothelium).
✓ Secondary glaucomas:
▪ Secondary open-angle glaucoma: if the
trabecular meshwork is clogged with acute
inflammatory cells of toxic iritis.
▪ Pupillary block glaucoma: if toxic iritis results in
posterior synechiae formation between the
back surface of the iris and the anterior capsule
of the lens. This causes pupillary block with the

32
 iris pushing forward which leads to angle
closure.
▪ Secondary angle closure from peripheral
anterior synechiae: if the angle is closed by
synechiae formation from toxic iritis.
✓ Complications of healing corneal ulcers:
▪ Nebula: if the opacity is faint and the pupil/iris
details are evident from behind.
▪ Leucoma: if the opacity is dense enough to
hide the underlying pupil/iris details.
▪ Perforated healed ulcers:
o Leucoma non-adherent: if a small
central perforation.
o Leucoma adherent: if a small
paracentral or peripheral perforation (the
iris is adherent to the corneal opacity as
the iris was pulled towards the perforation
site). The pupil peaks towards the
leucoma site.
o Anterior staphyloma: if a large corneal
perforation occurs, where it heals by a
scar and granulation tissue formation
lined by uveal tissue. This is usually a
blind painful eye.

• Management of a bacterial corneal ulcer:

33
✓ Corneal scraping (for culture, and also for
debridement of the necrotic tissue and decreasing
the organism load to enhance the effect of topical
treatment).
✓ Don’t wait for culture results and start empirical
topical antibiotic eye drops (fortified
vancomycin/gentamycin drops for severe
conditions and single topical monotherapy for
milder cases).
✓ The topical antibiotics should start with a high
frequency (around the clock), then gradual
tapering is performed according to the patient’s
response to treatment.
✓ If the culture results reveal a different antibiotic
regimen, do not change treatment except if the
patient is not improving on the current empirical
treatment. Hence, monitoring the symptoms and
signs is crucial in management.
✓ If there is toxic iritis or hypopyon formation, add
topical mydriatic eye drops to the topical antibiotic
treatment. This should be prescribed twice daily to
keep the pupil playing, hence preventing the
development of posterior synechiae or peripheral
anterior synechiae in cases having significant toxic
iritis.

34
 ✓ The use of topical steroids should be avoided as
much as possible, for fear of disturbed local
immunity with flare-up of infection.
✓ In very resistant ulcers, a therapeutic corneal graft
can be a radical treatment. However, an intense
topical antibiotic regimen should ensue
immediately after graft surgery to avoid the
recurrence on the graft.
✓ Management of corneal opacities following
corneal ulcers:
▪ Nebulas are treated by phototherapeutic
keratectomy (ablated by laser) or lamellar
keratoplasty.
▪ Leucomas are treated by deep lamellar or
penetrating keratoplasty (according to the depth of
the stromal opacity).
▪ These corneal opacities (especially the denser
ones) should be well addressed early in younger
ages to avoid sensory deprivation amblyopia.

Infective Viral Keratitis (Herpes Simplex):

• Herpes simplex virus (HSV) is an epitheliotropic and
neurotropic DNA virus. HSV type I causes ocular (above
the waist) infections, whereas type II causes genital (below

35
 the low waist) infections (yet type II HSV can cause keratitis
in cases of ophthalmia neonatorum).
• Infection by HSV can spread from herpetic lesions around
the mouth, and also iatrogenically through the Goldmann
applanation tonometer head and other contaminated
equipment in Ophthalmology clinics.
• Primary herpetic infection can present as either mild or
severe systemic viral invasion (depending on the patient’s
immune response). The primary attack may even be
subclinical. Afterward, the organism remains dormant in
the ciliary or trigeminal ganglia and flares up with lowered
immunity (mainly stress, steroid use, and other viral
illnesses).
• Clinical picture of HSV Keratitis:
▪ Symptoms:
❖ Mild stitching pain or discomfort.
❖ Redness.
❖ Reflex lacrimation.
❖ Symptoms are usually mild due to diminished corneal
sensation (HSV causes hypoesthesia by affecting the
corneal nerve endings, which is progressive with
recurrent attacks).
▪ Signs:
❖ Punctate or stellate fluorescein staining of the
corneal stroma → shedding in a linear, branching

36
 fashion → dendritic ulcer (branching with terminal
knobs).
❖ Geographical ulcer “amoeboid” (induced by steroid
use due to compromised local immunity).
❖ Stromal infiltration is usually superficial and mild with
no residual dense opacities and no deep penetration
(except if steroids are used, which leads to a
deepening of the ulcer with secondary bacterial
infections).
❖ HSV may also present with follicular conjunctivitis or
blepharitis. The primary infection may even present
with these extraocular symptoms sparing the cornea.
• Differential diagnosis of herpetic dendritic ulcer
(pseudo-dendritic ulcers):
✓ Herpes zoster.
✓ Acanthamoeba keratitis.
✓ Healing corneal abrasions.
✓ Toxic epitheliopathy with abuse of topical eye
drops containing preservatives.
• Treatment of herpetic keratitis (dendritic ulcer):
✓ Topical acyclovir 3% ointment with gradual
tapering over two weeks.
✓ Systemic antiviral treatment is reserved for
recurrent cases with lowered immunity.

37
Infective Viral Keratitis (Herpes Zoster):
• Varicella Zoster is a dermatomal virus that may affect
the eye if it involves the ophthalmic division of the
trigeminal nerve.
• Ophthalmic division affection is associated with
papillomacular eruptions along the innervated skin
areas.
• Ocular involvement is highly suspected if the skin
eruptions involve the tip of the nose or the medial
canthus (indicating nasociliary nerve affection, which
is an ophthalmic nerve branch that supplies sensory
innervation intraocularly).
• Herpes Zoster keratitis resembles herpes simplex,
although it is usually more virulent. It typically
presents with pseudo-dendritic keratitis, with
possible associated conjunctivitis and less
commonly intraocular involvement (mainly uveitis,
trabeculitis, and scleritis).
• Treatment involves combined topical and systemic
antiviral therapy.

Infective Fungal Keratitis:

• Fungi are opportunistic pathogens that usually infect eyes
with compromised local immunity (prolonged abuse of
steroids or topical antibiotics).
38
• Trauma of a plant origin is usually reported in the history of
fungal keratitis. This may cause an infection even in a
healthy eye with no compromised local immunity.
• Clinical picture of fungal keratitis:
❖ Symptoms:
✓ History of trauma of a plant origin is common.
✓ The eye is red, yet ocular pain with reflex
lacrimation and photophobia are significantly
milder than cases of bacterial corneal ulcers,
as the fungal hyphae coat the sensory nerve
endings reducing the corneal sensation.
❖ Signs:
✓ Ciliary injection (circumcorneal or peri limbic
injection).
✓ Positive fluorescein staining of the corneal
stroma due to corneal epithelial defect.
✓ Greyish-white, feathery stromal opacity with
satellite lesions away from the main lesion.
✓ Hyphae usually penetrate the intact
Descemet’s membrane causing pseudo-
hypopyon (it does not contain true pus as it is
mainly formed of fungal hyphae).
• Treatment includes topical (may be combined with systemic
if needed) antifungal agents (mainly miconazole and
nystatin).

39
Infective Acanthamoeba Keratitis
• Acanthamoeba is a protozoan that lives in brackish water
(so it lives in swimming pools with stagnant water). Its cystic
form can survive under hostile conditions in "chlorinated
swimming pools". When it finds its proper host, the cysts
adhere to the corneal epithelial cells and release the
trophozoites which start an enzymatic tissue destruction of
the corneal epithelium and stroma.
• Corneal abrasion is not a must for penetration of
acanthamoeba, yet the corneal epithelium is usually
compromised from prolonged soft contact lens wear.
• Risk factors for developing infections on top of contact lens
wear include improper cleaning of contact lenses “with tap
water or homemade saline”, wearing the contact lenses
while swimming, or being a regular contact lens wearer with
improper hygiene or sizing.
• Acanthamoeba and Pseudomonas are the most common
infections on top of soft contact lens wear.

• Clinical picture of acanthamoeba keratitis:

❖ Symptoms:
✓ The patient commonly gives a history of regular contact
lens wear and recent use of swimming pools.
✓ Pain out of proportion to signs.
✓ Ocular redness.
❖ Signs:
40
 ✓ Ciliary injection.
✓ Pseudo-dendritic ulcers.
✓ Radial kerato-neuritis (this is the reason for intense ocular
pain, as the organism concentrates around the corneal
nerve endings).
✓ Ring-shaped (annular) infiltrates develop afterward.
✓ Diagnosis may be difficult and may require a corneal
biopsy.
• Treatment is with topical propamidine isethionate (brolene).

Non-infectious Keratitis:
Neurotrophic keratitis:
• It is a central corneal ulcer with punched-out edges
and superficial stromal infiltration.
• It is caused by chronic diminished corneal sensation
(recurrent attacks of herpes, recurrent trigeminal
neuralgia, or abuse of topical anesthetics), which
leads to loss of the neurotrophic factors released by
the sensory nerve terminals, which are essential for
epithelial integrity. The epithelium is denuded, mainly
from the central area.
• The central ulcer is associated with diminished or lost
corneal sensation and is very resistant to treatment.
• Amniotic membrane grafts and autologous serum
with frequent lubricants can improve the condition.

41
 Exposure keratopathy:
• It is a lower corneal epithelial defect with intact corneal sensation.
• It occurs when the corneal surface is exposed, mainly with
paralytic ectropion (facial palsy), other causes of ectropion, or
proptosis.
• The lower corneal portion is the most exposed area to damage,
especially while sleeping at night, causing exposure keratopathy.
• A poor Bell’s phenomenon usually exaggerates the condition.
• Treatment of the cause is mandatory with symptomatic treatment
(frequent lubricants).

Corneal Degenerations:
Arcus Senilis
• It is an age-related lipid deposition at the peripheral corneal
stroma (near the limbus).
• This lipid deposition is separated from the limbus by a clear
zone (Lucid interval of Vogt).
• The patient should be reassured that this is a benign
condition that requires no treatment.
• If this lipid deposition develops at a young or middle age,
arcus juveniles is the name of the condition and it indicates
serum hyperlipidemia. Referral to an internist for a lipid
profile is mandatory.

42
Band Keratopathy
• It presents as a greyish band within the cornea (formed of
calcium deposition at the level of Bowman’s layer and
superficial corneal stroma).
• It starts as a greyish band at the corneal periphery then
becomes more whitish and creeps towards the center. The
opacity usually spares black dots within it at the sites of
corneal nerve endings.
• Causes of band keratopathy:
✓ Systemic hypercalcemia (mainly hyperparathyroidism).
✓ Phthisis bulbi.
✓ Chronic uveitis.
✓ Silicon-filled eyes with emulsified silicon oil.
• Treatment of band keratopathy includes treatment of the
underlying cause and ablation of the deposits using EDTA
solution.

Keratoconus (Corneal Ectasia)

• This is a non-inflammatory corneal disease that starts with the
inherent weakness of corneal stroma and loss of collagen
cross-links between lamellae.
• Afterwards, stromal thinning and increased curvature lead to
corneal bulging or conical protrusion (usually at the inferior
corneal portion), hence the name keratoconus.

43
• It usually starts around puberty (10-20 years) with a
progressive course (usually stationary at around 40 years).
This is because the corneal cross-links increase with age, so
the disease progression ceases at older ages and patients
presenting at older ages usually have milder symptoms and
stationary courses.
• Keratoconus is typically a bilateral yet asymmetrical disease.
That is why the other eye must be followed up even if no
symptoms started in it.
• Family history is positive in 10%, while the rest of cases are
sporadic.
• Keratoconus is commonly associated with spring catarrh
(vernal keratoconjunctivitis), due to frequent eye rubbing that
aggravates the loss of stromal collagen cross-links.
• Clinical picture of keratoconus:
❖ Symptoms
▪ Frequent change of glasses (gradual progression).
▪ Intolerance to contact lens wear (progressive irregular
astigmatism).
▪ Gradual painless drop of vision.
❖ Signs:
▪ Irregular myopic astigmatism (detected by auto refractometer).
▪ Slit lamp examination shows stromal thinning and steepness
at the site of the cone (usually inferior). Also, Vogt striae
“vertical stress lines due to traction by the bulging cone” can
be seen within the corneal stroma at the upper corneal portion.

44
▪ Munson's sign: notching of the lower lid on downgaze due to
cone formation.
• Investigations for a case of keratoconus:
▪ Corneal topography/tomography (like the Pentacam
device)
✓ It has got color-coded maps for corneal elevations, thickness,
and curvatures.
✓ In curvature maps, the cone is a red (hot) spot, usually
inferiorly located.
✓ Corneal tomography can capture images for both the posterior
and anterior corneal surfaces with a full overview of the
cornea, so the disease can be discovered early.
✓ The posterior surface is commonly affected by keratoconus
before the anterior surface. Posterior corneal surface affection
does not significantly affect the patient’s visual acuity, so the
patient does not complain except if the pathology reaches the
anterior corneal surface. Hence, screening the corneas with
Pentacam can cause early detection of keratoconus and
hence earlier and proper interventions.
✓ Before undergoing LASIK vision correction, corneal
topography/tomography is a must to evaluate if the cornea is
fit for refractive correction. Nowadays, LASIK has become a
screening method for detecting early keratoconus before the
onset of visual complaints.
✓ LASIK is absolutely contraindicated in ectatic (keratoconic)
corneas.

45
• Complication of keratoconus:
Acute hydrops:
✓ With the progression of keratoconus, the cone bulges more
and causes stretching of the Descemet’s membrane which
may lead to its rupture.
✓ Descemet’s membrane rupture causes an influx of aqueous
humor inside the corneal stroma with the development of
keratitis that heals with dense opacity (leucoma non-
adherent).
✓ Treatment of such a condition usually requires deep lamellar
or penetrating keratoplasty.
• Treatment of keratoconus:
✓ Spectacles correction and follow-up for stationary cases in old
age.
✓ Rigid contact lenses can flatten the cone, but they do not stop
the pathology and are intolerable by many patients.
✓ Mild cases are best treated by corneal cross-linking (using
ultraviolet A to strengthen the collagen cross-links).
✓ Moderate cases (where corneal cross-linking cannot be
performed) are treated by implantation of intracorneal rings to
flatten the cone. They may require exchange with time as they
do not stop the ongoing pathology, which is the loss of stromal
collagen cross-links.
✓ Severe cases or cases with corneal scarring are treated by
performing keratoplasty.

46
 Sclera

Anatomy of the Sclera:

• It is the opaque posterior four-fifths of the outer coat of the globe.

• It is continuous with the transparent cornea at the corneoscleral
junction (the limbus, which is an anatomical and surgical
landmark).
• The collagen bundles forming the sclera are irregularly arranged,
contrary to those of the corneal stroma. This is the main reason
for its white, opaque color.
• The sclera attains its full rigidity around the age of 13 years. That
is why younger ages have elastic sclera. This is reflected in the
elongation of the globe in cases of increased intraocular pressure
with congenital glaucoma (buphthalmos).
• The sclera proper is avascular. It receives its blood supply from
the superficial and deep vascular plexuses of blood vessels,
which are both located in the episcleral tissue. Furthermore, the
choroid shares in the blood supply of the posterior sclera.
• Causes of blue sclera:
✓ Young age (sclera is thin and elastic).
✓ High axial myopia (scleral stretching with globe
elongation).
✓ Congenital glaucoma (buphthalmos).
✓ Osteogenesis imperfecta (abnormal collagen synthesis
with associated deafness and fragile bones).

47
Diseases of the Sclera:

Episcleritis
Scleritis
Staphylomas

Episcleritis
• It is an inflammation of the superficial vascular plexus in the
episcleral tissue.
• It may be idiopathic (with no associated diseases) or may be
attributed to autoimmune collagen diseases (suspected with
recurrent attacks of episcleritis).
• It may be simple episcleritis (involving a sector of the episclera
or a diffuse inflammation) or it may be nodular episcleritis (a
tender nodule, usually in a middle-aged person which resembles
a phlycten in appearance). It usually causes mild symptoms of
redness, discomfort, and ocular irritation.
• It is usually self-limiting and only requires local non-steroidal anti-
inflammatory eye drops or steroidal drops for symptomatic relief
of ocular discomfort. Yet, a systemic workup for associated
autoimmune collagen diseases is required with recurrent attacks.

48
Scleritis
• It is an inflammation of the deep vascular plexus of the
episcleral tissue.
• It is usually associated with autoimmune collagen
diseases, and a workup for such diseases should be
initiated with the occurrence of the first attack of scleritis
(as collagen diseases are outer coat diseases that
commonly cause associated keratitis or scleritis).
• It presents with deep-seated ocular pain and redness, with
associated intraocular involvement (uveitis) in some
instances.
• The main differentiating clinical test between episcleritis
and scleritis is by instillation of topical phenylephrine 10%
eye drops, where it blanches the vessels in episcleritis (due
to the superficial location of the affected vascular plexus)
and does not blanch the vessels in scleritis (due to the
deep location of the affected plexus within the episcleral
tissue).
• Treatment requires systemic steroids, and
immunosuppressives can also be used in severe
conditions.

49
 Staphylomas
• They represent the bulging of the outer coat lined by the
middle coat.
1- Anterior Staphyloma
• It occurs due to a large central perforation of a corneal
ulcer, with scar and granulation tissue formation that is
lined by iris tissue. The scar bulges under even normal
intraocular pressure and the eye is usually blind and
painful.
2- Posterior Staphyloma
• It occurs with large (pathological) axial myopia.
3- Scleral Staphyloma
• It occurs with recurrent attacks of severe scleritis that
cause inherent weakness and thinning of the scleral tissue
that bulges, lined with ciliary body or choroidal tissue. This
is usually a blind painful eye.

✓ In cases of anterior and scleral staphylomas with blind

painful eyes, evisceration or enucleation is commonly
performed (according to the scleral condition, where
evisceration requires intact sclera for artificial eyeball
implantation).

50
 Lacrimal System

Anatomy of the Lacrimal System:

• The lacrimal system comprises a secretory and an excretory

portion.
• The secretory portion consists of the main lacrimal gland (located
in the upper lateral part of the orbit, having both orbital and
palpebral parts) and the accessory lacrimal glands of Krause and
Wolfring (located in the palpebral conjunctival tissue).
• The lacrimal glands are exocrine glands that pour their
secretions (aqueous portion of the tear film) through ducts into
the fornices and then it is distributed by the lid movements onto
the outer corneal surface. The accessory lacrimal glands provide
basal tear secretion, while the main lacrimal gland provides the
reflex tear secretion.
• The aqueous portion of the basal tear film provides nutrition,
oxygenation, and local immunity to the corneal epithelium and
superficial corneal stroma.
• The excretory portion of the lacrimal system comprises two
puncti, upper and lower canaliculi, and common canaliculus,
then a lacrimal sac that collects the tears to pass to the
nasolacrimal duct, which opens into the inferior meatus of the
nose.
• The lacrimal sac lies mainly below the medial canthal tendon.
That is why the swelling in cases of acute dacryocystitis is below
the medial canthal area.
51
 • Proper tear drainage requires a proper apposition between the
lid margin and the globe for proper flow of tears (with the aid of
the lacrimal pump action of the orbicularis oculi muscle that helps
in the suction of tears into the lacrimal sac “on lid closure” then
pushing the tears into the nasolacrimal duct “on lid opening”).

Diseases of the Lacrimal System:

Chronic Dacryocystitis
Acute Dacryocystitis
Causes of Eye Watering

Chronic Dacryocystitis
• It is a chronic inflammation of the lacrimal sac.
• It results from nasolacrimal duct obstruction, which may be
caused by:
✓ Congenital anomaly (imperforation of Hasner’s valve “a
mucous membrane fold” at the end of the nasolacrimal
duct at the inferior nasal meatus).
✓ Acquired obstruction of the nasolacrimal duct (mainly in
postmenopausal females with proliferation of nasolacrimal
duct epithelium).
• Symptoms of chronic dacryocystitis:
✓ Eye-watering.
52
 ✓ Associated conjunctivitis and mucopurulent discharge.
✓ Painless swelling at the medial canthus.
• Signs of chronic dacryocystitis:
✓ Epiphora.
✓ Swelling below the medial canthal tendon with no signs of
acute inflammation.
✓ Positive regurge test (mucoid or mucopurulent discharge).
• Differential diagnosis of eye-watering in a newborn:
✓ Chronic dacryocystitis (congenital nasolacrimal duct
obstruction), which is the most common cause.
✓ Congenital glaucoma (buphthalmos), which is the most
serious cause and is associated with increased corneal
diameter and reflex ocular irritation “photophobia and
blepharospasm on light exposure”.
✓ Ophthalmia neonatorum (by herpes simplex type II).
• Complications of chronic dacryocystitis:
✓ Spread of infection causing corneal ulcers.
✓ Acute infection on top (acute dacryocystitis).
• Treatment of congenital dacryocystitis:
✓ Massaging the lacrimal sac area by daily multiple strokes
(directed downwards and medially) to create a positive
pressure and open the imperforate Hasner’s valve. This is
usually done till the age of one year (waiting for
spontaneous valve opening with the help of the lacrimal
massage). Topical antibiotics can be used for associated
conjunctivitis.

53
 ✓ Probing and syringing of the lacrimal passages with saline
irrigation is done after one year of age. A silicon tube may
also be inserted in the lacrimal passages to keep them
open.
✓ Surgical intervention (DCR operation) is delayed till three to
four years of age with failure of the aforementioned
treatment options.
• Treatment of acquired dacryocystitis:
✓ Surgical intervention is indicated, performing the dacryo-
cysto-rhinostomy “DCR” surgery, creating a pathway from
the lacrimal sac directly to the middle meatus of the nose
(above the obstruction site) bypassing the area of
nasolacrimal duct obstruction. A silicon tube is usually
inserted in the lacrimal passages during surgery to prevent
the closure of the lacrimal passages by any edema or
bleeding, and it is removed after a few months.

Acute Dacryocystitis
• It is an acute suppurative infection (usually
staphylococci, streptococci, or pneumococci) of the
lacrimal sac on top of chronic obstruction.
• It presents with a painful, red, hot, tender swelling
below the medial canthal tendon in the medial
canthal area.

54
 • It may be complicated by a lacrimal abscess, orbital
cellulitis, or even the spread of infection through the
orbital veins to the cavernous sinus causing
cavernous sinus thrombosis.
• Treatment must be initiated by hot fomentations and
systemic antibiotics with no trials to press on the sac
(to avoid the spread of infection). Following the
resolution of the acute condition, DCR surgery must
be performed to avoid the recurrence of the acute
infection and to keep proper extraocular hygiene to
guard against keratitis.

Eye Watering
1- Causes of Lacrimation (reflex over secretion):
✓ Corneal irritation by foreign bodies or rubbing lashes.
✓ Reflex lacrimation from intraocular inflammations (mainly
keratitis, scleritis, and uveitis).
2- Causes of Epiphora (blocked drainage):
✓ Blocked upper lacrimal passages (starting from the puncti
to the common canaliculus) by inflammatory or fibrotic
reactions, with trachoma being one of the commonest
causes in endemic slum areas of Egypt.
✓ Blocked lower lacrimal passages (lacrimal sac and
nasolacrimal duct) by a foreign body or nasal causes
“polyps or inflammations”.
55
 ✓ Lacrimal pump function failure with orbicularis oculi
paralysis (facial nerve palsy).
3- Investigations for Causes of Eye Watering:
✓ Examine the globe for all possible causes and check the
existence of ocular irritants (causing lacrimation) and also
check for any lacrimal passage obstruction or improper
apposition of the lid margin to the globe (causing epiphora).
✓ Fluorescein dye disappearance test (the dye should
disappear from the ocular surface in less than five minutes
if there is no epiphora).
✓ Regurge test is positive in nasolacrimal duct obstruction
and negative in canalicular obstruction.
✓ Radiological tests for lacrimal passages patency
(dacryocystography and scintillography with radioactive
scanning).
✓ ENT consultation to exclude nasal causes.

56
 Dry Eye

Anatomy of the Tear Film:

• The tear film should homogenously cover the whole corneal surface.
• It is formed of three layers:
✓ Outer lipid layer: secreted by the meibomian glands of the
tarsus, and is responsible for lubricating the cornea with
continuous eyelids movement against the cornea during
blinking, together with retardation of evaporation of the
aqueous tear film layer.
✓ Middle aqueous layer: it is the thickest layer of the tear film,
secreted from the lacrimal glands (basal secretion is mainly by
accessory glands and reflex tearing by the main gland). This
layer is responsible for nutrition, oxygenation, and local
immunity providence for corneal epithelium and superficial
stroma. It is also responsible for giving the eye its lustrous
appearance.
✓ Inner mucin layer: secreted by the goblet cells of the
conjunctiva, and its hydrophilic nature allows the adherence
between the aqueous layer of the tear film and the microvilli of
the corneal epithelial cells, stabilizing the tear film.

57
Abnormal Tear Film (Dry Eye):

Causes
Symptoms
Signs
Investigations
Treatment

Causes
1- Decreased tear film secretion:
✓ Decreased aqueous portion (keratoconjunctivitis sicca)
• Autoimmune Sjogren’s Syndrome (middle-aged
females with autoimmune destruction of lacrimal
glands “xerophthalmia” and associated autoimmune
destruction of salivary glands “xerostomia”).
• Scarring of the conjunctiva (destruction of the
accessory lacrimal glands, mainly with trachoma).
• Surgery: LASIK affects the subepithelial plexus of long
ciliary nerves, affecting aqueous tear film secretion.
✓ Decreased mucin portion (xerosis)
• Vitamin A deficiency.
• Scarring of the conjunctiva (mainly with trachoma).

58
2- Increased tear film evaporation:
✓ Deficiency of the lipid portion (congenital distichiasis).
✓ Exposure keratopathy or lagophthalmos (facial palsy,
proptosis, ectropion).

Symptoms
• Ocular discomfort and burning.
• Ocular redness.
• Eye watering (paradoxical, due to reflex lacrimation from ocular
irritation, stops with the progression of dryness afterward).
• In severe cases, decreased reflex tearing with emotions is
noticed.

Signs
• Loss of corneal luster.
• Decreased tear meniscus level (normally 0.2 to 0.4 mm).
• Increased tear film debris.
• Conjunctivochalasis (folds in the conjunctival tissue).
• Punctate epithelial erosions with severe conditions (due to
affection of corneal epithelial nourishment by the tear film).
• With vitamin A deficiency, Bitot spots are common. They are
chalky white, foamy patches at the bulbar conjunctiva that are
formed due to the effect of xerosis bacilli on the dead and
keratinized conjunctival epithelium.

59
Investigations
• Fluorescein dye Break Up Time: time from a blink to the
appearance of cracks in the tear film, which should exceed 10
seconds in normal conditions and is less than 10 seconds with
dry eye (mainly in cases of mucin layer deficiency, indicating
tear film instability).
• Schirmer test: wetting of the Schirmer paper should exceed 10
mm in 5 minutes under normal conditions. In cases with
aqueous layer deficiency, it is less than 10 mm wetting and even
less than 5 mm in severe conditions.
• Rose Bengal (or Lissamine green) stains: they stain dead,
devitalized conjunctival epithelial cells, mainly with mucin layer
deficiency. Lissamine green is less irritant than Rose Bengal.

Treatment
• Treatment of the cause.
• Tear substitutes (artificial tears).
• Vitamin A therapy with Bitot spots.
• Punctal occlusion with punctal plugs in severe conditions.

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 Lens

Anatomy of the Lens:

• The crystalline lens is the second major refractive surface of the

globe (sharing by 16-17 diopters of the ocular refractive power).
• It is attached to the ciliary body by suspensory ligaments, which
allow the action of the ciliary muscle on it during the process of
accommodation.
• Accommodation:
❖ It is the ability of the crystalline lens to change its refractive
power at different distances to obtain a clear, sharp image
focused on the retina.
❖ This is achieved by continuous contraction and relaxation
of the ciliary muscle, with the transfer of its action to the
crystalline lens, as follows:
✓ When we look at a near object, the ciliary muscle
contracts (concentrically through its circular portion),
so the suspensory ligaments become relaxed, which
allows the anterior surface of the crystalline lens to
increase its curvature forwards, which in turn
increases the lens refractive power to focus the near
object on the retina.
✓ When we look at a far object, the ciliary muscle
relaxes, so the suspensory ligaments become tight,
which in turn pulls the anterior surface of the
crystalline lens backward, reducing its curvature and
61
 hence its power, focusing the far object sharply on
the retina.
• The lens is surrounded by an elastic capsule and is formed of a
central nucleus and a peripheral cortex.
• The anterior capsule is lined by subcapsular epithelium, which is
cubical at the central portion and then elongates towards the
equator of the lens, whereas the posterior capsule is devoid of an
epithelial lining.
• The equatorial subcapsular lens epithelium is responsible for the
continuous production of new lens fibers throughout human life.
• Starting from the embryonic development of the lens, the older
fibers are always pushed to the inner part of the lens (forming the
nucleus) and the newer fibers are formed in the peripheral cortex.
• As newer fibers are formed, they push the older ones towards the
nucleus in the center, and the central fibers become more and more
desiccated, where nuclear sclerosis develops with older ages.
• The crystalline lens is totally avascular, and it relies upon the
aqueous humor in its nutrition and metabolism. Hence,
disturbances in the aqueous humor (as in cases of glaucoma) lead
to pathological affection of lens metabolism and cataract formation.

Diseases of the Lens

Congenital Cataract
Complicated or Secondary Cataract
62
Senile Cataract
Complications of Cataract
Management of Cataract
Ectopia Lentis

Congenital Cataract
• It refers to any lenticular opacity dating since birth.
• Causes:
❖ Hereditary (autosomal dominant).
❖ Intrauterine maternal infections (mainly rubella).
❖ Metabolic diseases (mainly galactosemia).
❖ Hypocalcemia.
• Types:
❖ Anterior or posterior polar (posterior location affects
vision more significantly).
❖ Lamellar (Cartwheel appearance with riders) with
hypocalcemia, where rickets and teeth troubles are
often associated.
❖ Nuclear (with galactosemia “oil globule” and rubella
“pearly white”).
❖ Others (as coronary, blue dot, and sutural). They are
usually innocuous.

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 • The child’s mother or the child (with older ages) complains
of a gradual painless drop of vision and white pupil
(leukocoria).
• Significant congenital cataracts should be removed early to
guard against amblyopia.
• When the cataract is more dense, more central, posterior in
its location, and/or unilateral, it is more commonly
associated with amblyopia and needs earlier intervention.
• Differential diagnosis of leukocoria in a child:
✓ Congenital cataract (the most common).
✓ Retinoblastoma (the most serious).
✓ Retinopathy of prematurity.
✓ Cyclitic membrane at the ciliary body with
intermediate uveitis.
✓ Coat’s disease (lipid exudations and edema at the
macular area).

Complicated or Secondary Cataract

• It is a cataract that is secondary to ocular or systemic causes, as
follows:
❖ Ocular causes:
✓ Pathological high axial myopia.
✓ Open-angle glaucoma.

64
 ✓ Attacks of angle closure glaucoma
(glaucomfleckens, which are infarctions of the
capsule and subcapsular epithelium).
✓ Chronic anterior uveitis.
✓ Traumatic cataract (with blunt trauma, known as
concussion cataract, which is an imprint of the
posterior iris epithelium that is formed on the anterior
lens capsule (Vossius ring).
❖ Systemic causes:
✓ Diabetes Mellitus.
✓ Hypoparathyroidism.
✓ Systemic steroid therapy.

• The complicated cataract is usually posterior subcapsular in

location with a polychromatic luster, then it may spread to cause
total cataract.

Senile Cataract
• It is a progressive lens opacification that occurs with aging
without the existence of any ocular or systemic causes of
cataract formation.
• It presents with a gradual painless drop of vision (more visual
affection with posterior, dense, and/or central cataract location),
and also presents with abnormal discoloration of the pupillary
area (greyish, whitish, yellowish, or brownish).
65
• Types:
❖ Anterior and posterior subcapsular.
❖ Nuclear: exaggeration of the physiological nuclear
sclerosis, so the nucleus attains a denser greyish color, or
becomes yellowish or brownish with the abnormal
deposition of urochrome pigment.
❖ Cortical: starts as spoke-like greyish white cortical
opacifications during the early (incipient) stage, then
changes to denser immature cortical cataract, then total
cortical opacification resulting in a mature cortical cataract.
❖ Hypermature: in advanced cases of cortical cataract, the
lens fibers become liquified and the lens capsule becomes
shrunken with calcium deposition on the anterior lens
capsule. Hence, the cataract changes from the mature to
the hypermature stage. In more severe cases with both
nuclear and cortical cataract, the nucleus sinks down within
the liquified cortical matter (morgagnian cataract).

• Visual affection with various types of cataracts:

✓ Posterior subcapsular cataract causes more blurring
of vision than its anterior counterpart and also causes
night glare with pupillary dilatation at night.
✓ Nuclear cataract causes index myopia and a myopic
shift of refractive power (known as second sight,
where the patient takes off his presbyopic
spectacles).
66
 ✓ Cortical cataract can cause fixed musca volitans and
haloes around the light (water vacuoles within the
lens fibers act as a prism). It also causes blurred
vision up to counting fingers.
✓ Hypermature cataract causes significant visual
affection up to hand motion (but not less). It is liable
for the development of complications (see below).

Complications of Cataract
1- Ectopia Lentis:
✓ Abnormal location of the lens with progressive
(hypermature) cataract development.
✓ The lens may be subluxated or dislocated into the
anterior or posterior segments.
2- Secondary Glaucomas (drop of vision changes from
painless to painful with red eye):
✓ Phacomorphic glaucoma: in some cases of immature
cortical cataract, the lens capsule becomes permeable
to aqueous humor which enters the lens, with lens
intumescence resulting in pupillary block and
subsequent secondary angle closure glaucoma.
✓ Phacolytic glaucoma: in cases of hypermature cortical
cataract, the liquified (denatured) lens proteins can pass
through the intact shrunken lens capsule, causing a
macrophages-induced inflammatory reaction in the
anterior chamber (yet a mild reaction, as the proteins

67
 are denatured with low antigenicity). These
macrophages laden with lens proteins can clog the
trabecular meshwork leading to secondary open-angle
glaucoma.
✓ Lens subluxation or dislocation: when this happens
anteriorly, it results in pupillary block and secondary
angle closure glaucoma. When the dislocation is
posterior, the vitreous itself can cause a pupillary block.

Management of Cataract
• The conventional treatment of cataract is surgical cataract
extraction and intraocular lens (IOL) implantation (this
intraocular lens will substitute the refractive power of the
original crystalline lens).
• First and foremost (before any surgical intervention), there
must be good control of elevated intraocular pressure (if any)
before management of the cataractous lens.
• Good history taking is mandatory to evaluate if cataract is
significantly affecting daily life activities, as this is the major
indication for intervention.
• In cases of congenital cataract, unilateral significant cataracts
(dense, central, and/or posterior) should be removed as early
as possible to guard against stimulus-deprivation amblyopia.
• A full preoperative ocular evaluation should be performed,
excluding any other ocular pathologies that may be the cause
of visual affection (mainly retinal and optic nerve diseases).
68
• Any extraocular infections should be excluded or treated
before surgery (blepharitis, conjunctivitis, or dacryocystitis) to
guard against postoperative endophthalmitis.
• Biometry should be accurately performed, which is the
calculation of the intraocular lens power. This is done using
A-scan ultrasound to assess the axial length and corneal
keratometry to assess corneal power. Nowadays, this is
performed through an IOL Master device that performs both
steps.
• Surgical extraction of cataract:
❖ If the patient is young (less than 10 years), lensectomy is
better performed. This includes the removal of the cataractous
lens together with part of the posterior capsule and the
anterior vitreous face. This is done to prevent severe
postoperative fibrosis that may occur and obscure vision.
❖ If the nucleus is soft (ages of 10-25 years), irrigation/aspiration
of the cataractous lens fibers is usually easily performed.
❖ If the nucleus is hard (more than 25 years), the opening of the
anterior lens capsule and phacoemulsification of the nucleus
should be performed (using ultrasonic waves), followed by
irrigation/aspiration of the remaining cortical lens matter.
❖ If the nucleus is very hard (brown cataract), using massive
amounts of ultrasonic waves can cause damage to the
corneal endothelium. In this condition, a large corneal incision
is performed to deliver the hard nucleus, followed by
irrigation/aspiration of the remaining cortical lens matter. This

69
 surgical technique is known as extracapsular cataract
extraction (ECCE). This is usually complicated by a large
postoperative astigmatism due to the large wound (which is
avoided by the small, self-sealed wound in
phacoemulsification).
❖ Nowadays, femto-laser is used in wound creation and
opening of the anterior lens capsule.
• Visual rehabilitation following cataract extraction:
❖ Medical glasses: this is a bad option as there will be no
implanted intraocular lens (IOL) that supports the vitreous
face, so these patients (who are left aphakic) are liable for
vitreous prolapse into the anterior chamber and are also liable
for retinal detachment due to vitreous prolapse. Furthermore,
unilateral aphakia that is corrected by glasses results in
anisometropia and diplopia.
❖ Posterior Chamber Intraocular Lenses (PC-IOLs,
Pseudophakia): this is the best option for visual
rehabilitation. There are available foldable IOLs that are
implanted following the phacoemulsification technique. They
can be implanted from small wounds to avoid larger wounds
causing induced astigmatism.
❖ Anterior Chamber IOLs: these are resorted to with capsular
damage during surgery that makes the surgeon unable to
implant the IOL on the remaining posterior capsular support.
This anterior chamber location of the IOL can lead to

70
 postoperative complications, including mainly uveitis from iris
rubbing and secondary glaucoma from angle compromise.
• Postoperative complications:
❖ Posterior Capsule Opacification (PCO, After Cataract):
these are fibrotic proliferations of any remaining capsular
epithelium or lens fibers following surgery. They cause whitish
opacification of the pupillary area behind the implanted IOL
and reduce vision once again. The posterior capsule should
be opened centrally by performing a small Nd-YAG laser
posterior capsulotomy.
❖ Endophthalmitis: this is mainly caused by the spread of
extraocular infections inside the globe if they were not
adequately addressed preoperatively. It can also be caused
by intraoperative infections from the operating theatre
personnel or equipment. Any hypopyon appearing
postoperatively should raise suspicion of endophthalmitis.
❖ Retained lens matter: this can lead to secondary uveitis and
uveitic glaucoma. That is why proper cleaning of all the lens
matter should be performed.
❖ Induced astigmatism: from large corneal wounds with
extracapsular cataract extractions to remove a very hard lens
nucleus.
❖ Amblyopia: in young children within the critical period,
improper management of cataract can lead to this serious
complication.

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Ectopia Lentis
• It refers to any lens displacement from its normal position.
• Causes:
❖ Trauma.
❖ Hypermature senile cataract.
❖ Marfan syndrome (abnormally tall stature, increased
arm span to height ratio, arched palate, and
cardiomyopathies).
❖ Metabolic disorders (mainly homocystinuria).
• Lens Subluxation:
❖ It is a partial lens displacement.
❖ It results in astigmatism (affecting vision) and
uniocular diplopia (as the pupillary area now
comprises both phakic and aphakic portions).
❖ If the lens subluxation occurs with a densely
cataractous lens, there will be no diplopia, as the
brain will not receive an image from the phakic
cataractous pupillary portion.
❖ On slit lamp examination, the lens appears displaced
with evident suspensory ligaments, and the iris and
lens are tremulous.
❖ It causes rubbing against the iris with uveitis and
secondary glaucoma, and it may also displace into
the anterior or posterior segments.

72
 ❖ Subluxated lenses causing any symptoms or
complications should be surgically removed with IOL
implantation.
• Anterior Lens Dislocation:
❖ This anterior lens position induces a myopic shift of
refraction.
❖ The lens appears as an oil globule in the anterior
chamber.
❖ The lens rubs against the corneal endothelium
causing its damage and against the iris with
secondary uveitis and uveitic glaucoma.
❖ It can also cause angle compromise.
❖ It further causes pupillary block glaucoma with
elevated intraocular pressure.
❖ This lens should be immediately removed.
• Posterior Lens Dislocation:
❖ This posterior lens position induces a hyperopic shift
of refraction.
❖ The pupillary area is jet black (aphakic), with the lens
seen lying on the retina when performing
ophthalmoscopy.
❖ The vitreous face causes pupillary block glaucoma,
and it may be complicated by retinal detachment.
❖ This condition is less dangerous than its anterior
counterpart, where surgical intervention is an elective

73
 procedure without the need for urgent interference
before proper patient preparation

Uvea

Anatomy of the Uveal Tract:

• The uveal tract is the middle coat of the globe, which is

comprised of the iris, the ciliary body, and the choroid.
• It contains variable amounts of melanin pigment. The iris color
depends on the amount of melanin. There is a high melanin
concentration in the choroid, giving it its dark brown color.
• The iris tissue contains both the sphincter and the dilator pupillae
muscles, which are responsible for the control of the amount of
light reaching the retina through pupillary constriction (miosis
with sphincter pupillae contraction) and dilatation (mydriasis with
dilator pupillae contraction).
• The ciliary body contains a circular and a longitudinal portion of
the ciliary muscle. The circular portion is responsible for the
direct effect of the ciliary muscle on the crystalline lens through
the suspensory ligaments (accommodation reflex), while the
longitudinal portion contraction pulls on the scleral spur of the
anterior chamber angle and widens the angle, increasing the
aqueous outflow.
• The ciliary body contains 70 ciliary processes at the pars plicata,
whereas the remaining surface of the ciliary body without ciliary
processes is known as the pars plana. These ciliary processes

74
 are covered with an outer pigmented and an inner non-
pigmented epithelium, where the inner non-pigmented
epithelium plays a major role in aqueous production.
• Choroidal tissue provides nutrition for the outer retinal layers
(retinal pigment epithelium and photoreceptors).
• There is a blood-aqueous barrier that exists in the form of the
tight junctions between the endothelial cells of the iris capillaries
and also the tight junctions between the non-pigmented
epithelium of the ciliary body. This blood-queous barrier prevents
the blood contents (proteins and inflammatory cells) from
reaching inside the globe. Disruption of this barrier (by physical
or chemical injuries or inflammatory reactions) leads to plasmoid
aqueous.

Diseases of the Uvea:

Acute Iridocyclitis (Acute Anterior Uveitis)

Complications of Acute Iridocyclitis
Workup for a case of Acute Iridocyclitis
Treatment of Acute Iridocyclitis
Chronic Iridocyclitis
Endophthalmitis
Panophthalmitis

75
Acute Iridocyclitis (Acute Anterior Uveitis)
• It is an acute inflammation of the iris and ciliary body
(mainly containing neutrophils as the major contributing
inflammatory cells).
• Causes of acute anterior uveitis:
❖ Exogenous agents: leading to infectious
endophthalmitis (infected hypopyon).
❖ Endogenous agents: leading to non-infectious acute
inflammation (sterile hypopyon).
• Causes of endogenous (non-infectious) uveitis:
1- Systemic diseases:
✓ Seronegative spondylo-arthropathies (HLA B27):
mainly ankylosing spondylitis which presents with
lower back pain (sacroiliitis).
✓ Granulomatous diseases: mainly sarcoidosis
which presents with respiratory symptoms due to
non-caseating lung granulomas, and sometimes
skin and CNS granulomas.
✓ Behcet’s disease (HLA B5): usually presents in
young males with painful aphthous oral ulcers and
genital ulcers, with associated phlebitis (can
present with central retinal vein occlusion).
✓ Vogt-Koyanagi-Harada Syndrome: presents with
alopecia, poliosis of the lashes and hair, vitiligo,
and recurrent attacks of iridocyclitis and exudative

76
 choroiditis (which may lead to exudative retinal
detachment).
✓ Juvenile rheumatoid arthritis: usually presents in
young females, where the iridocyclitis is usually
chronic and asymptomatic (may present late with
complications, so requires regular ocular
screening).
2- Ocular diseases:
✓ Keratitis and scleritis (outer coat inflammation).
✓ Ectopia lentis (lens rubbing against the iris).
✓ Reactions following trauma:
▪ Phaco-anaphylactic uveitis: in cases of
the ruptured lens capsule and the lens fibers
are healthy without any cataract. These lens
fibers are highly proteinaceous (antigenic),
so if they are dispersed into the anterior
chamber, they induce an acute inflammatory
response.
▪ Sympathetic ophthalmitis: it is a bilateral
granulomatous panuveitis that occurs due to
the liberation of uveal pigments from their
capsules within the iris epithelium, where the
other (healthy) eye sympathizes with the
traumatized eye and develops the same
granulomatous reaction against the iris

77
 melanin pigment (this reaction reaches the
healthy eye through the bloodstream).
✓ Reaction to drugs: mainly two pressure-lowering
topical drops “prostaglandin analogues (as
latanoprost) and miotics”, so these agents should
not be used to control the intraocular pressure in
eyes with uveitic glaucoma.
✓ Masquerade uveitis: these are some ocular
conditions that can uncommonly present as uveitis
(mainly tumors “retinoblastoma and lymphoma”
and intraocular foreign bodies).
• Clinical picture of acute anterior uveitis (acute
iridocyclitis):
❖ Symptoms:
✓ Pain (dull aching in nature) with reflex lacrimation,
photophobia, and blepharospasm.
✓ Ocular redness.
✓ Drop of vision.
❖ Signs:
✓ Ciliary body tenderness.
✓ Ciliary (circumcorneal) injection.
✓ Dropped visual acuity (mainly due to plasmoid
aqueous and ciliary body spasm).
✓ Keratic precipitates (KPs) on the corneal
endothelium: presents with a triangular
inflammatory corneal precipitate (with base down).

78
 The inflammatory cells are whitish in acute cases
and become pigmented later. The inflammatory
cells are mainly neutrophils in acute inflammations
(small-sized) and macrophages in chronic
granulomatous inflammations (large-sized, mutton
fat).
✓ Aqueous flare and cells (plasmoid aqueous):
due to disruption of the blood-aqueous barrier with
leakage of proteins and inflammatory cells.
✓ Sluggish, miotic pupil (whereas it is mid-dilated
in acute attacks of angle closure glaucoma). The
pupil may become irregular (festooned) with
complicated cases.
✓ The intraocular pressure: it is low in the early
phase due to ciliary body shutdown then it
increases progressively in many cases due to
secondary glaucomas or using topical steroids for
treatment.
Complications of Acute Iridocyclitis
1- Exudates and Reactions:
✓ Posterior synechiae: due to adhesions between
the back surface of the iris and the anterior capsule
of the lens (mainly by the effect of fibroblasts as
one of the inflammatory mediators). These
synechiae cause:

79
 ▪ Festooned pupil: this happens with partial
posterior synechiae formation, in which there
is irregular pupillary dilatation on applying
topical mydriatics, where the areas with
adhesions fail to dilate and those without
adhesions dilate.
▪ Secclusio pupillae: this happens with
complete posterior synechiae formation,
where the whole pupillary area fails to dilate.
▪ Occlusio pupillae: this happens when the
adhesions involve the whole pupillary area
(masking it) together with the existence of
secclusio pupillae.
✓ Peripheral anterior synechiae: this happens
when the adhesions involve the angle of the
anterior chamber.

2- Secondary (uveitis-induced) glaucomas:

✓ Secondary open-angle glaucoma due to clogging
of the trabecular meshwork by inflammatory cells.
✓ Pupillary block glaucoma due to posterior
synechiae and occlusio pupillae, with consequent
secondary angle closure.
✓ Peripheral anterior synechiae with consequent
secondary angle closure.

80
 3- Secondary cataract:
✓ It is usually a posterior subcapsular cataract with
polychromatic luster, then it may progress to a
total cataract.
✓ Cataract may be caused by the uveitis itself
(affecting the aqueous circulation that nourishes
the lens) or may be caused by using steroids in
the treatment of uveitis, where topical steroids
more commonly elevate the intraocular pressure
and systemic steroids more commonly cause
secondary cataract.

4- Complications of chronicity:
✓ Band keratopathy (calcium deposition at the
Bowman’s layer and superficial stroma).
✓ Iris atrophic patches.
✓ Synechiae formation.
✓ Atrophia bulbi with persistent glaucoma (ciliary
body damage with suppressed aqueous
production).

N.B. Aqueous cells are the most important sign that denotes the
existence of active uveitis, as aqueous flare sometimes persists after
subsidence of the acute attack due to disruption of the blood/aqueous
barrier.

N.B. Patients with chronic uveitis are more liable to the development
of complications.
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N.B. The development of synechiae formation can start with the active
uveitic stage, but it is usually a consequent complication after the
subsidence of the acute attack, and it is more commonly encountered
in chronic cases.

N.B. The existence of synechiae alone without any aqueous cells or

keratic precipitates indicates old attacks of uveitis (most commonly in
chronic or recurrent acute cases).

Workup for a case of Acute Iridocyclitis

• Proper history taking and ocular examination.
• Systemic investigations for the aforementioned
causes of uveitis.

Treatment of Acute Iridocyclitis

• Steroids: mainly topical treatment and systemic only if needed
(in severe and bilateral conditions). You should push steroids
with high doses first then perform a gradual tapering.
• Short-acting mydriatic cycloplegics (atropine derivatives
like tropicamide): to keep the pupil playing all day preventing
the complications of synechiae formation. If synechiae have
already formed, atropine eye drops should be used to break the
existent synechiae. Guard against atropine toxicity (especially in
children) by compression on the medial canthus for three
minutes after drop instillation to reduce systemic absorption from
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 the vascular plexus around the lacrimal sac and nasolacrimal
duct.
• Immunosuppressive drugs: in severe and resistant conditions.
• Treatment of the cause.
• In treating uveitis-induced glaucoma, avoid using miotics or
prostaglandin analogues as they already induce uveitis, and they
can exaggerate the condition.

Chronic Iridocyclitis
• It is an iridocyclitis with a chronic nature, which presents
with no or mild symptoms and the patient can directly
complain of its complications.
• It is usually a granulomatous uveitis and has a recurrent
nature.
• Mutton fat keratic precipitates and iris nodules are
characteristic of chronic uveitis (representing aggregates
of macrophages).
• Vogt-Koyanagi-Harada Syndrome, sarcoidosis, and
sympathetic ophthalmitis are among the commonest
causes of chronic granulomatous uveitis (they all cause
chronic granulomatous panuveitis).
Endophthalmitis
• It is an acute suppurative inflammation of the middle and
inner coats of the globe.
• It may be caused by:

83
 ❖ Exogenous infections (trauma, surgeries, or perforated
corneal ulcers) or endogenous infections (mainly fungal
endophthalmitis in immunosuppressed individuals).
❖ Non-infectious (sterile) endophthalmitis can also occur
(less frequently) and is usually a reaction to chemical
agents (such as talc powder in surgical gloves).
❖ However, any post-traumatic or post-operative
inflammatory reactions should be considered infectious
endophthalmitis until proven otherwise.
• It presents as a drop of vision that may reach up to the
perception of light. The ocular examination reveals corneal
edema and significant uveitis with hypopyon.
• If endophthalmitis is suspected:
❖ Aqueous and vitreous samples should be withdrawn for
cultures.
❖ A B-scan ultrasound should be performed to evaluate the
existence of a vitreous abscess (especially since the
fundus view of the posterior segment is usually obscured
by corneal and anterior chamber affections).
• Treatment of endophthalmitis involves:
❖ Vitrectomy (to remove the vitreous that acts as a blood
agar to the pathogens and is the major cause for the
flare-up of infections) with intravitreal injection of broad-
spectrum antibiotics (usually a combination of
vancomycin/cephalosporin).

84
 ❖ If fungal endophthalmitis is suspected, intravitreal
amphotericin is usually added.
❖ If the eye is a blind painful one (no perception of light),
evisceration is indicated to prevent the spread of infection
to the outer coat.
• Prophylaxis against postoperative endophthalmitis is one
of the major prerequisites for attaining satisfactory
postoperative outcomes. It mainly involves:
❖ Proper examination of the ocular adnexa to exclude or
treat any extraocular infections (mainly blepharitis,
conjunctivitis, or dacryocystitis) before any surgical
intervention.
❖ Pre-operative instillation of diluted povidone-iodine in the
fornices and over the ocular surface for three minutes
then wash it (for sterilization of the ocular surface before
the start of intraocular surgeries).
❖ Lashes isolation to be away from the surgical field.
Panophthalmitis
• This is an acute suppurative inflammation of all the ocular
coats.
• It presents in the same picture as endophthalmitis, with
additional corneal abscess and scleritis. Furthermore,
proptosis and limited ocular motility (due to the spread of
infection to the orbit causing orbital cellulitis) also exist.
• Panophthalmitis should be properly addressed to prevent
orbital cellulitis and cavernous sinus thrombosis (if the
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 infection spreads through the ophthalmic veins to the
cavernous sinus).
• Panophthalmitis should be treated by evisceration. Never
perform enucleation for such a condition, as manipulations
in the inflamed scleral tissue can spread the infection
causing orbital cellulitis and cavernous sinus thrombosis.

Glaucoma

Physiology of Aqueous Humor Formation and

Intraocular Pressure:

• The aqueous humor is the fluid that fills the anterior

segment of the eye, including the anterior chamber (from
the cornea to the iris) and the posterior chamber (from the
posterior surface of the iris to the posterior capsule of the
lens).
• Disturbances in aqueous circulation within the globe lead
to the development of glaucoma.
• The aqueous humor is responsible for controlling the
intraocular pressure to be within the normal values, which
is crucial for maintaining proper functioning of all
intraocular structures, especially the avascular structures
that rely upon the aqueous for nourishment and washing
away the metabolites, namely the cornea (stroma and
endothelium) and the crystalline lens.

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• The aqueous humor is secreted by active secretion (ATP-
dependent) that occurs at the non-pigmented epithelium
covering the ciliary body, with a minor portion of the
aqueous humor produced by passive diffusion from the
ciliary body vessels.
• Carbonic anhydrase enzyme and beta receptors within the
non-pigmented ciliary epithelium play a vital role in
aqueous production. That is why beta-blockers and
carbonic anhydrase enzyme inhibitors are used as anti-
glaucoma treatment. Contrarily, alpha receptors play an
inhibitory role in aqueous production and hence alpha
agonists are one of the anti-glaucoma treatment
modalities.
• Aqueous drainage depends on the trabecular meshwork
(angle of the anterior chamber), which represents 80% of
the aqueous drainage pathway, while the uveal-scleral
outflow (through the uveal and scleral surfaces then into
the systemic circulation) constitutes 20% of the normal
aqueous drainage and circulation within the globe.
• The normal value of the intraocular pressure (IOP) is 10-
21 mm Hg. However, what is more important than the
numerical value is the effect of this pressure on various
ocular structures, especially the retinal nerve fiber layer
and hence the optic nerve fibers.
• Occurrence of a diurnal variation of more than 4 mm Hg
within the same eye (maximal IOP value at 11 am and

87
 minimal at 6 pm) or difference of more than 4 mm Hg
between both eyes are among the earliest signs of
glaucoma (before the elevation in the numerical value of
IOP above the normal range).
• The IOP is measured using tonometry, which can be:
❖ Digital: by fingers, giving an average estimate.
❖ Goldmann applanation tonometer: attached to the
slit lamp, which is accurate but can transmit
infections due to its contact nature.
❖ Air puff tonometer: not as accurate as applanation
tonometer, but non-contact and does not transmit
infections, so it is used in screening but not for follow-
up of glaucoma.
❖ Tonopen: Hand-held and easy to use, but still not as
accurate as the applanation tonometer.
N.B. IOP measurement by applanation tonometer is affected by
corneal thickness, so corneal pachymetry is performed at the
baseline (before starting the follow-up of any glaucomatous patient)
to assess if there is any over or underestimation of IOP.

Anatomy of the Angle of the Anterior Chamber

• The angle of the anterior chamber from inside the globe
corresponds to the limbic area (limbus) from outside. It
consists of the following structures from anterior to
posterior:

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❖ Schwalbe’s line: termination of Descemet’s
membrane of the cornea.
❖ Trabecular meshwork: the major component of the
angle, which is sieve-like, where the pores decrease
in size gradually towards the end of the angle
exteriorly (to control the aqueous outflow out of the
angle).
❖ Scleral spur: it is a scleral projection where the
longitudinal portion of the ciliary muscle attaches.
❖ Ciliary body band.
❖ Root of iris: obvious in high axial myopes.
❖ Canal of Schlemm: from which the aqueous leaves
the angle to reach the episcleral veins then the
systemic circulation.
N.B. By gonioscopy and ultrasound biomicroscope,
we can visualize the angle. Without such techniques,
we cannot see it due to the optical phenomenon of
total internal reflection (where the light rays emerge
from the angle of the anterior chamber by an angle
greater than the critical angle at the cornea/air
interface, so the light undergoes total internal
reflection, and we cannot visualize the angle).
N.B. Both the trabecular meshwork and the ciliary
body appear as dark brown structures.

89
Glaucoma Classification

❖ According to age: congenital or acquired.

❖ According to cause: primary or secondary.
❖ According to angle status: open angle or closed angle.
❖ Absolute glaucoma (glaucoma fulminans): end-stage of any
glaucoma type with a blind painful eye.

Buphthalmos

• It is any elevation in IOP in children under three years of age.

• The disease has an autosomal dominant inheritance nature, so
the siblings of a diseased child should be closely followed up till
the age of three years.
• It is a bilateral asymmetrical disease; hence the other eye should
be closely followed up.
• It is known as buffalo eyes due to the enlarged globe size with
elevated IOP due to the high elasticity of the pediatric sclera
(which attains adult rigidity around the age of 13 years). This
enlarged size is protective of the retinal nerve fibers.
• The most common cause of buphthalmos is the existence of
Barkan’s membrane over the angle of the anterior chamber,
hence blocking the trabecular outflow of aqueous. In other cases,
the canal of Schlemm is congenitally absent, and this form of
buphthalmos is severe and presents very early.
• Clinical picture of buphthalmos:
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❖ Symptoms:
✓ Reflex lacrimation and photophobia are one of the
earliest symptoms (due to reflex irritation of the long
ciliary nerve endings of the cornea from the influx of
aqueous humor inside the corneal tissue with
elevated IOP).
✓ Large globe or bull’s eye (more noticed if unilateral
or bilateral yet significantly asymmetrical, as the
scleral elasticity allows the globe to stretch easily
with elevated IOP).
✓ Blue sclera with progressive stretching (due to the
more obvious appearance of the underlying
choroidal venous blood with scleral stretching, and
also due to scattering of light by choroidal pigments
with blue light being the most widely scattered).
✓ Defective vision progressively develops.
❖ Signs:
✓ Pseudo-proptosis (Bull’s eyes).
✓ Increased horizontal corneal diameter (normally
around 10 mm at birth, measured by caliper).
✓ Haab’s striae at the cornea (horizontal striae due to
stretching of the Descemet’s membrane).
✓ Hazy cornea develops with aqueous influx inside the
cornea with elevated IOP.
✓ Deep anterior chamber and wide angle.

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 ✓ Lens subluxation or dislocation with widened anterior
chamber and elongated globe.
✓ Blue sclera.
✓ Optic disc cupping (this is partially reversible, as a
major portion of this “obvious” cupping can be
attributed to scleral stretching that widens the scleral
canal through which the optic nerve fibers emerge
from the optic disc outside the globe, so it can be
partially reversible with treatment of buphthalmos
and regaining the normal globe dimensions).
N.B. If the fundus view is hazy, a B-Scan ultrasound must be
performed to visualize the posterior segment and exclude
retinoblastoma, which may present with buphthalmos.

• Complications of buphthalmos:
❖ Corneal scarring with persistent aqueous influx and
reactive keratocyte-induced fibrosis.
❖ Secondary ectopia lentis and cataract formation.
❖ Amblyopia if not properly treated early (due to hazy vision).
• Treatment of buphthalmos:
❖ Treatment is mainly surgical, removing the existent
Barkan’s membrane.
❖ If the cornea is clear, a goniotomy is performed using a
gonio lens to open the trabecular meshwork.
❖ If the cornea is hazy, trabeculotomy from outside (without
visualization) is performed.

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 ❖ In advanced severe cases or cases with an absent canal
of Schlemm, sub-scleral trabeculectomy (SST) surgery is
performed. In this surgery, a new pathway is opened
between the anterior chamber and the subconjunctival
space, excising a block of the trabecular meshwork, and
leaving a scleral flap for controlled aqueous outflow to the
subconjunctival space. Then the aqueous flows from the
conjunctival vessels to the episcleral vessels and then to
the systemic circulation. It is a sophisticated surgery that
needs proper performance and proper follow-up
thereafter.
❖ If SST surgery fails, a shunt operation is performed with
a silicon tube inserted into the anterior chamber that
drains the aqueous humor directly into an implant that is
placed on the sclera, with aqueous drained into the
systemic circulation thereafter. Proper follow-up must be
closely performed to guard against complications of such
a major surgical intervention.

Primary Angle Closure Glaucoma (PACG)

• It refers to a type of glaucoma with a closed angle

(iridocorneal touch peripherally, where the peripheral iris
closes the angle).
• Demography:

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 ❖ Age: it is common for those above 40 years, where the
lens enlarges with progressive nuclear sclerosis or
senile cataract and hence pushes the iris forward.
❖ Sex: it is more common in females.
❖ Laterality: it is a bilateral yet asymmetrical disease, so
the other eye must be closely monitored, and proper
prophylaxis against possible attacks in the other eye
must be performed.
❖ Family history: positive in some cases.

• Pathogenesis:
❖ Angle-closure glaucoma needs a precipitating factor in
an anatomically predisposed eye:
✓ Anatomical predisposition for ACG:
o Hypermetropia with a shallow anterior chamber
and narrow angle.
o Exaggeration of physiological iris bombe pattern by
enlarged lens with increasing age and nuclear
sclerosis. This increases the risk of pupillary block
followed by angle closure.
✓ Precipitating factor for an attack of ACG:
o Semi-dilated pupil on exposure to
darkness or upon using mydriatics, so
pupillary block develops followed by
angle closure by peripheral iris.

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 o Prone position with a congested ciliary
body that can close the angle by
pushing the iris forward.
• Stages of ACG:
1- Prodromal (intermittent) stage of ACG:
❖ In this stage, a partial closure of the angle occurs
followed by rapid reopening (on miosis with exposure to
light or on reversing the prone position, where the
sphincter pupillae muscle contracts and pulls the iris
away from the angle relieving the closure).
❖ Clinical picture:
o Symptoms:
✓ Ocular pain and headache (dull and deep-
seated pain, due to compression on ciliary
nerves by the congested globe from blocked
aqueous drainage and elevated IOP).
✓ Ocular redness.
✓ Drop of vision.
✓ Halos around the light (as the aqueous drops
enter the corneal stroma with increased IOP
and act as a prism with light splitting into
spectrum colors).
o Signs:
✓ Ocular tenderness.

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 ✓ Ciliary injection (due to blocked vascular
drainage of the globe with elevated IOP and
blocked aqueous drainage).
✓ Dropped visual acuity.
✓ Corneal edema (due to influx of aqueous into
the corneal stroma).
✓ Elevated IOP.
❖ In between the attacks, there are no obvious signs,
except for the existence of anatomical predisposing
factors. Hence, if the patient is seeking medical advice
after subsidence of a prodromal stage, history taking
and signs of anatomical predisposition are the only
clues for diagnosis.
❖ Treatment:
✓ The patient must be properly counseled that
although this attack resided, it can recur and
cause more damage with every recurrence (as
each attack can heal by synechiae formation that
can progressively close the angle), so a
prophylactic intervention must be performed.
✓ Bilateral peripheral iridotomy (PI) is the treatment
of choice, to guard against recurrence in this eye
or development of attacks in the other eye (that
has the same anatomical predisposition). By
performing the PI, the aqueous passes directly

96
 through it from the posterior to the anterior
chamber, hence bypassing the pupillary area.
✓ The location of the PI is usually between 11 and 1
O’clock, and at the peripheral third of the iris, to be
covered by the eyelid to avoid double pupils that
can cause uniocular diplopia.

2- Acute (Congestive) stage of ACG:

❖ In this stage, there is a total closure of the angle by the peripheral
iris, and it cannot reopen easily like the prodromal stage. This is
because the angle closure is total with a significant increase in
IOP that causes ischemic paralysis of the sphincter pupillae
muscle, so it cannot react to light exposure by miosis.
❖ Symptoms:
✓ Severe (bursting) ocular pain and headache (due to total
angle closure with complete blocking of aqueous
circulation and severe ocular congestion). Pain may be
associated with reflex vomiting.
✓ Marked ocular redness.
✓ Drop of vision.
✓ Halos around the light.
❖ Signs:
✓ Marked ocular tenderness and stony hard globe.
✓ Significant ciliary injection.
✓ Dropped visual acuity (up to perception of light, from
marked corneal edema and maybe optic nerve ischemia).

97
 ✓ Severe corneal edema (due to aqueous influx into the
stroma with marked IOP elevation).
✓ Shallow or even lost anterior chamber (if it can be seen
from behind the significant corneal edema).
✓ Semi-dilated irreactive pupil (due to ischemic paralysis of
sphincter pupillae from elevated IOP).
✓ Stony hard IOP (difficult to measure due to patient’s agony
from pain. It can exceed 60 mm Hg).
❖ Treatment:
✓ This is considered an ocular emergency that must be
properly and promptly treated (as the significant elevation
of the IOP can lead to optic nerve ischemia or central
retinal artery occlusion).
✓ The attack is treated surgically, but only after medical
control of the condition (to avoid opening the globe with
severe IOP elevation that can lead to expulsive
hemorrhage).
✓ Medical preparation:
o Hyperosmotic agents (mannitol 20% IV drip over
half an hour) are the best choice for rapid lowering
of the IOP, but cardiac and renal problems should
be highly considered, and the dose should be
adjusted accordingly.
o Beta-blockers (topical) and carbonic anhydrase
enzyme inhibitors (IV or oral) should follow the

98
 mannitol infusion to reduce the aqueous
production.
o Topical miotics will not give any response before
proper control of IOP, due to sphincter pupillae
paralysis from severely elevated IOP.
✓ Surgical intervention:
o Following medical control of IOP, gonioscopy should
be done to evaluate the angle of the anterior
chamber:
➢ If less than half the angle is blocked by post-
inflammatory synechiae formation, bilateral
peripheral iridotomy can be performed.
➢ If more than half the angle is occluded by
synechiae, sub-scleral trabeculectomy (SST)
with PI must be performed. In this case,
prophylactic PI for the other eye is mandatory
to guard against the development of similar
attacks.
o Some surgeons recommend lens removal with the
development of attacks of ACG, especially in the
existence of associated cataract. This can markedly
reduce the IOP and prevent the recurrence of
attacks, as it relieves one of the major anatomically
predisposing factors.

3- Chronic stage of ACG:

99
 ❖ To reach this stage, the patient will have experienced multiple
recurrent attacks (due to improper management).
❖ With each attack, progressive angle closure develops with
peripheral anterior synechiae (post-inflammatory fibrosis in the
angle).
❖ Due to its progressive nature, there are no signs of acute attacks,
and the patient starts to develop symptoms reminiscent of
primary open-angle glaucoma (with progressive field loss).
❖ If the patient is not properly examined and no history was taken
about previous attacks of ocular pain, he may be treated as a
case of open-angle glaucoma.
❖ That is why proper history taking and ocular examination
(especially gonioscopy) are key steps before starting any
glaucoma treatment.

N.B. Since the manifestations of ACG arise rapidly and should be

managed rapidly too, progressive optic nerve damage does not usually
occur, except in cases that progress to chronic ACG with recurrent
prodromal or acute attacks. This is because the optic nerve fibers are
not crowded together and can withstand elevated IOP for variable time
intervals (depending on the viability and sensitivity of the fibers).

Primary Open Angle Glaucoma (POAG)

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• It refers to progressive retinal nerve fiber layer and optic
nerve fiber damage with corresponding visual field defects,
where elevated IOP is a common association.
• The damage usually arises due to mechanical pressure on
the fibers, ischemic affection of the vasa nervorum of the
corresponding fibers, and/or apoptotic damage
(programmed cell death).
• The angle of the anterior chamber is not closed, but there
is rather trabecular sclerosis and resistance to the aqueous
outflow.
• Demography:
❖ Age: it usually manifests above 40 years.
❖ Sex: no sex predilection has been reported.
❖ Laterality: it is a bilateral asymmetrical disease, so
the other eye of a glaucomatous one should be
closely monitored.
❖ Family history: is positive in some cases.

• Clinical picture:
❖ Symptoms:
✓ POAG is known as the silent killer of the optic nerve, as it
does not present with early symptoms (except when the
central visual field is affected late along the disease
course. As the disease is bilateral asymmetrical, field
defects of one eye are usually covered by the other “still
normal” eye).

101
✓ That is why screening for glaucoma for any middle-aged
person above 40 years should be performed (especially if
he is at high risk, e.g.: high myope or on long-term topical
steroids).
✓ One of the presenting symptoms can be early presbyopia
(as glaucoma hinders proper aqueous circulation and
therefore affects normal lens metabolism).
❖ Signs:
✓ Elevated IOP above 21 mm Hg is usually
present (although diurnal variation above 4 mm
Hg or difference between both eyes more than
4 mm Hg may precede elevated IOP values).
✓ The angle of the anterior chamber is open with
no signs of synechial closure. That is why angle
examination is important to exclude secondary
causes of glaucoma or angle closure glaucoma
before tagging the patient as having primary
open angle glaucoma.
✓ Fundus: progressive optic disc cupping (the
normal cup-to-disc ratio is 0.2-0.3 mm), where
the optic nerve fibers are replaced by glial
tissue after their glaucomatous atrophy, as
follows:
o Cupping starts inferior, then superior, then nasal,
then temporal optic disc edge cupping comes last.

102
 o This is according to the portions of the optic disc
receiving retinal nerve fibers from various retinal
areas, where the lower temporal retinal fibers are the
most crowded arcuate fibers, and they converge to
pass through the lower border of the optic disc, that
is why this is the first edge to show glaucomatous
cupping.
o The upper temporal arcuate fibers of the retinal nerve
fiber layer are less arched than the lower temporal
ones, and they converge to pass through the upper
edge of the disc.
o The nasal fibers are less arched, passing through the
nasal edge of the optic disc.
o The papillo-macular bundle is the least crowded
bundle with no arching fibers, so it is the final one to
experience glaucomatous damage. As the papillo-
macular bundle passes through the temporal edge of
the optic disc, this is the last edge to show
glaucomatous cupping.
• Field changes of POAG (detected by perimetry):
❖ Field defects are known as scotomas.
❖ Glaucomatous field defects are horizontal and
always respect the horizontal raphe, contrary to
visual pathway lesions that cause vertical field
defects.

103
 ❖ They follow the same course as the damaged retinal
nerve fibers and optic nerve fibers, where the field
defect corresponds to the retinal area that
experiences glaucomatous damage.
❖ Upper retinal fiber damage causes lower field defects
and vice versa, and temporal fiber damage causes
nasal field defects and vice versa.
❖ As the lower temporal fibers are the earliest to be
damaged by glaucoma, upper nasal field defects
present early, followed by the lower nasal field, then
the temporal field.
❖ The field defect takes an arched pattern like the
arching of the retinal nerve fibers (arcuate
scotomas).
❖ The central field is preserved till late due to the
preserved papillo-macular bundle. This is known as
a tubular field. Here the visual acuity may still be
normal, but the patient experiences visual problems
on crossing the street or driving and feels that things
pop up on his way.
❖ Lost central field leads to absolute glaucoma with
total field loss in advanced cases.
• New investigative modalities for POAG:
❖ OCT nerve fiber layer and optic nerve head: it
shows early changes before field defects and optic
disc cupping.

104
 ❖ Short Wave Automated Perimetry (SWAP): also
detects early glaucomatous damage.
• Treatment of POAG:
❖ POAG requires topical medical rather than surgical
treatment.
❖ The patient should be properly counseled about the
disease risk to be ready to comply with the medical
treatment for his lifetime, especially since the patient
does not usually complain early along the disease
course.
❖ Instruct the patient about how to avoid systemic
absorption of the drops by pressing on the medial
canthus for 3 minutes.
❖ Topical eye drops include:
✓ Beta-blockers (such as timolol): decrease
aqueous production. It may cause bradycardia
and bronchospasm and patients with cardiac or
pulmonary problems should avoid them, yet
selective beta-blockers (acting only on
aqueous production at ciliary epithelium) are
now available.
✓ Carbonic anhydrase enzyme inhibitors
(such as dorzolamide): decrease aqueous
production but are not as potent as beta
blockers and are usually used in combination
eye drops (such as cosopt which is combined

105
 timolol and dorzolamide). They are used alone
mainly to control IOP elevations for short
durations (as following some surgeries). They
cause hypokalemia with a tingling sensation
and can predispose to renal stones with
prolonged use.
✓ Prostaglandin analogues (as latanoprost):
increases uveoscleral outflow of aqueous, and
it is a potent antiglaucoma treatment but can
cause hyperpigmentation of skin and iris,
lengthening of lashes and increase of their
number, together with inflammatory uveitis in
some cases. That is why it should be avoided
in uveitic glaucoma.
✓ Alpha 2 agonists (as brimonidine): reduce
aqueous production and also increase
uveoscleral outflow, but not commonly used
due to their noxious side effects such as dry
mouth and reported apnea in children (due to
their potent sympathomimetic effects).
✓ Miotics (as pilocarpine): They widen the
angle and can help to increase aqueous
drainage through the trabecular meshwork, but
they cause blurred vision and inflammatory
uveitis so better avoided.

106
 ❖ If two types of antiglaucoma eye drops fail to control
the IOP and progressive optic nerve damage is still
ongoing, argon laser trabeculoplasty can be
performed to widen the trabecular meshwork, but
there is a high incidence of failure and post-LASER
fibrosis and relapse of the condition.
❖ Surgical intervention (by performing sub scleral
trabeculectomy) is usually performed on the failure of
medical treatment or if the patient cannot afford the
cost of lifelong drops or cannot withstand their side
effects.

Ocular Hypertension

• It refers to elevated IOP above 21 mm Hg but without associated

damage to nerve fibers.
• This patient is not glaucomatous yet, but he is considered a
glaucoma suspect and should be followed up for possible
glaucoma development.

Normal-Tension Glaucoma

• It refers to progressive nerve fiber damage while the IOP is below

21 mm Hg.
• It is common with vasospastic diseases (mainly migraine and
Raynaud’s phenomenon).

107
Secondary Glaucomas

• Infectious corneal ulcers:

❖ Toxic iritis with secondary open-angle glaucoma: if
inflammatory cells block the trabecular meshwork.
❖ Angle-closure glaucoma: if synechiae formation
develops.
• Iridocyclitis (anterior uveitis):
❖ Open-angle glaucoma: inflammatory cells block the
trabecular meshwork.
❖ Pupillary block: posterior synechiae formation.
❖ Angle-closure glaucoma: due to pupillary block or
peripheral anterior synechiae formation at the angle.
• Lens-induced glaucomas: mainly phacomorphic,
phacolytic, and phacoanaphylactic uveitis.
• Retinal ischemia: neovascular glaucoma (mainly with
proliferative diabetic retinopathy and ischemic type of
central retinal vein occlusion with release of VEGFs).
• Steroid use: especially topical use and especially in
steroid responders.
• Intraocular tumors:
❖ Space-occupying lesions.
❖ Push the iris/lens diaphragm forward toward the
angle.
❖ Invade the angle directly.
❖ Tumor induces ischemic neovascular glaucoma.

108
 ❖ Tumor seedling induces secondary open-angle
glaucoma by blocking the trabecular meshwork.
❖ Tumor induces secondary uveitis and uveitic
glaucoma.

Absolute Glaucoma

• It is the end stage of any type of glaucoma with failed treatment.

• The vision and field are totally lost, and the eye is blind and
painful.
• Symptomatic relief is performed by cyclodestruction of the ciliary
body, using either LASER or cryotherapy.
• If there is no pain and the eye becomes atrophic with ciliary body
shutdown (atrophia bulbi which causes cosmetic disfigurement),
evisceration and artificial ball implantation on the scleral scaffold
are performed.

109
 Retina

Anatomy of the Retina:

• The retina is the inner transparent layer of the globe.

• It appears orange-brown in color due to the color of the
underlying choroidal vasculature and pigments of the choroid
and the retinal pigment epithelium.
• The retina acts as the film of the camera where the image is
formed and then transmitted through the optic nerve to the rest
of the visual pathway reaching the occipital lobe of the brain.
• The central part of the retina is known as the macula lutea, which
is 5.5 mm in diameter, and the center of which is known as the
fovea centralis, which is a 1.5 mm diameter area (one disc
diameter).
• The fovea centralis contains only cones and is responsible for
the central sharp vision. As we move away from the fovea
centralis, the number of cones decreases and the number of rods
increases, where the cones are responsible for sharp fine vision
and color vision (mainly during photopic conditions) and the rods
are responsible for coarse vision (mainly during scotopic
conditions and can detect dimmer light stimuli with higher
sensitivity than cones).
• The retina is mainly formed of ten layers, namely:
❖ Retinal pigment epithelium: the outermost layer that is
separated from the choroid by the Bruch’s membrane (to
which it is firmly adherent). It contains melanin pigments,
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 and it prevents light scattering throughout the retinal layers.
It also regulates the exchange of substances between the
choroid and retina.
❖ Photoreceptors layer (discs of rods and cones containing
the visual pigment “rhodopsin in rods and iodopsin in
cones”).
❖ External limiting membrane: formed of photoreceptors and
muller’s cells.
❖ Outer nuclear layer: nuclei of rods and cones.
❖ Outer plexiform layer: terminals of rods and cones
anastomosing with dendrites of bipolar cells.
❖ Inner nuclear layer: nuclei of bipolar cells (which are the
first-order neurons in the visual pathway).
❖ Inner plexiform layer: the axons of bipolar cells
anastomosing with the dendrites of ganglion cells.
❖ Ganglion cell layer: nuclei of ganglion cells (which are the
second-order neurons in the visual pathway).
❖ Nerve fiber layer: collection of axons of ganglion cells that
emerge from the optic disc to form the optic nerve fibers
that pierce the sclera to pass to the orbit, where the optic
nerve fibers pass in the optic canal to reach the middle
cranial fossa of the brain where they complete as optic
chiasma.
❖ Internal limiting membrane: formed of fibers of muller cells.
• The fovea centralis differs from the whole retina in that it only
consists of the outer retinal layers (retinal pigment epithelium,

111
 photoreceptors, outer nuclear, and outer plexiform layers). That
is why it appears darker in color than the rest of the retina, due
to the increased height and pigmentation of the retinal pigment
epithelium within the fovea centralis.
• The blood supply of the outer retinal layers (till the outer plexiform
layer) is derived from the choroid, whereas the inner retinal
layers (from the inner nuclear layer) are supplied by the central
retinal artery. That is why central retinal artery occlusion does not
affect the color of the fovea at the beginning of the lesion and a
cherry red spot is seen (as the fovea is only formed of the outer
retinal layers and there are no inner layers to be supplied by the
central retinal artery).

Diseases of the Retina:

Diabetic Retinopathy (DR)

Hypertensive Retinopathy
Central Retinal Vein Occlusion (CRVO)
Branch Retinal Vein Occlusion (BRVO)
Central Retinal Artery Occlusion (CRAO)
Branch Retinal Artery Occlusion (BRAO)
Retinitis Pigmentosa (RP)
Retinopathy of Prematurity (ROP)
Age-Related Macular Degeneration (AMD)
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 Retinal Detachment (Rhegmatogenous,
Tractional, and Exudative)

Diabetic Retinopathy (DR)

• Diabetic retinopathy (DR) is a bilateral retinal vasculopathy that

develops in patients with diabetes mellitus (mainly type II for long
durations). It is one of the leading causes of adult blindness
worldwide.
• Risk factors for developing DR:
❖ Duration of DM: there is a significant direct relation
between the duration of DM and the risk of DR, even with
control of the blood sugar levels.
❖ Metabolic control of blood sugar: can delay the onset of
DR.
❖ Associated risk factors that lead to microangiopathies:
mainly hypertension, hyperlipidemia, obesity, and
smoking.
❖ Pregnancy can aggravate the DR manifestations, and
pregnant diabetic females need close follow-ups.
• Pathology of DR:
1- Stage of microaneurysms and leakage:
❖ It starts as a microangiopathy that affects the retinal small
vessels (capillaries, arterioles, and venules).

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 ❖ This microangiopathy leads to damaged integrity of the
inner walls of these blood vessels, causing microaneurysm
formation.
❖ These microaneurysms have leaky walls, so there is
progressive leakage of fluids, hard exudates (lipids and
cholesterol), and then minute (dot and blot) hemorrhages
from the walls of these microaneurysms.
2- Stage of occlusion:
❖ After a longer period, endothelial proliferation of the
retinal small vessels develops, together with platelet
aggregation at these sites of endothelial proliferation.
❖ These proliferations cause narrowing of the lumen,
which results in ischemia of the retinal layers.
❖ This ischemia causes the release of angiogenic
(vasoformative) factors from the endothelial cells of the
small blood vessels. They are known as Vascular
Endothelial Growth Factors (VEGFs), which result in
many complications.
• Clinical picture of DR:
❖ Symptoms:
✓ The condition can be asymptomatic if the macular
area is not affected. This is common because the
pathology usually starts in the retinal mid-periphery.
✓ Gradual painless drop of vision develops with
macular affection (maculopathy).

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 ✓ Rapid painless drop of vision develops with the onset
of complications.
❖ Signs:
✓ Drop of visual acuity (according to macular affection).
✓ Pupil is sluggishly reactive to light, especially with
longer intervals of having DM. This is due to the
damaging effect of DM on the iris vessels and the
sphincter pupillae muscle.
✓ Fundus changes are variable according to the stage
of DR, as follows:
1- Non-Proliferative DR or Background DR:
o Retinal microaneurysms.
o Edema, hard exudates, and hemorrhages
around the retinal microaneurysms.
2- Pre-Proliferative DR:
o Venous beading.
o Soft exudates or cotton wool spots
(infarctions of the nerve fiber layer).
3- Proliferative DR:
o Neovessel formation due to the release of
VEGFS from ischemic retinal areas.
o Neovessels at the disc (NVDs) develop on
the optic disc or within 1.5 mm from the optic
disc.

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 o Neovessels Elsewhere (NVEs) develop on
the retinal surface but away from the optic
disc.
o Neovessels can also form in remote areas
with the dispersion of the VEGFs, including
the iris (rubeosis iridis) and the angle of the
anterior chamber (neovessels at the angle).
• Complications of DR:
❖ Bleeding from the fragile walls of the neovessels, leading
to vitreous hemorrhage.
❖ Organization of unresolved vitreous hemorrhage leads to
fibrosis of the blood that causes traction on the retina with
consequent tractional retinal detachment. This markedly
affects vision if the macula is affected.
❖ Neovessels at the angle lead to neovascular glaucoma.
❖ Leakage of fluids and exudates at the macula leads to
diabetic maculopathy, which affects vision.
❖ Ischemic changes at the macula lead to ischemic
maculopathy, which markedly affects vision.
• Investigations of DR:
❖ Monitor blood glucose level (especially HB A1C which
detects the control of blood sugar level over the past three
months).
❖ Fundus Fluorescein Angiography (FFA): it is the
investigation of choice to reveal all the microvascular
changes, including leakage and ischemic changes, and to

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 detect any diabetic maculopathy. It needs a relatively clear
view (no dense cataract or dense vitreous hemorrhage).
❖ Optical Coherence Tomography (OCT): it is the
investigation of choice to reveal the pathological changes
in the structure of the retinal layers (edema and traction on
the retina by organized vitreous hemorrhage). It needs a
relatively clear view (no dense cataract or dense vitreous
hemorrhage).
❖ OCT Angiography (OCTA): it shows both the
microvascular retinal circulation and the changes in the
retinal structure. It needs a relatively clear view (no dense
cataract or dense vitreous hemorrhage).
❖ B-Scan Ultrasound: performed in cases of blocked retinal
view by vitreous hemorrhage or organized vitreous
hemorrhage.
❖ Follow-up by fundus examination, FFA, OCT, and OCTA is
mandatory at regular time intervals (yearly in non-
proliferative and every 3 months in proliferative DR).

• Treatment of DR:
❖ Controlling the blood sugar level and the other risk factors
causing microangiopathies retard the development of
complications (but does not prevent them).
❖ Treatment of DR:
✓ LASER Treatments:

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 o In cases of diabetic maculopathy (leakage
involving the macular area with leaky
microaneurysms).
o Focal or diffuse (grid) LASER treatment for the
macular leaky areas around the
microaneurysms is performed.
o In cases with proliferative DR, pan-retinal
photocoagulation (PRP) is performed to
destroy the leaky fragile neovessels that may
cause vitreous hemorrhage and tractional
retinal detachment. LASER treatment should
involve the whole retina sparing the macula to
preserve central vision. Although the visual
field is affected, it is partially compensated for
by the other eye’s field and by the untreated
(spared) areas, and the macular area is now
saved from the possible complications of the
neovessels.
✓ Intravitreal Injections:
o Intravitreal triamcinolone: stabilizes the
vessel walls and reduces leakage but elevates
the intraocular pressure. It can be used in
cases of proliferative DR (in combination or as
an alternative to PRP LASER treatment).
o Intravitreal anti-VEGFs (Avastin, Lucentis,
Eylea): highly effective and commonly used in

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 proliferative DR (in combination or as an
alternative to PRP LASER treatment) and also
in non-proliferative maculopathy that is
refractory to LASER treatment.
✓ Vitrectomy with Endo LASER:
o In cases with persistent vitreous hemorrhage
or tractional retinal detachment threatening the
macular area.

Hypertensive Retinopathy

• It represents an arteriolar vasoconstriction response that occurs

in the retina due to chronic systemic hypertension.
• In addition to arteriolar vasoconstriction, there is a disruption that
occurs in the inner blood-retinal barrier (between the endothelial
cells of retinal small blood vessels), with resultant leakage of
edema fluid and hard exudates and also retinal hemorrhages,
followed by ischemic patches (cotton wool spots or soft
exudates).
• Malignant Hypertension:
❖ It is a sudden severe increase in arterial blood pressure
(mainly with phaeochromocytoma, pre-eclampsia, and
eclampsia).
❖ In response to this, there is disc edema (due to increased
intracranial pressure with severely elevated blood
pressure).

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 ❖ There are also massive exudations at the macular area,
with edema, hard exudates, hemorrhages, and cotton wool
spots.
❖ Deposition of exudates in the macular area forms what is
known as a macular star.
• Arteriosclerotic Hypertensive Retinopathy:
❖ With prolonged elevations of arterial blood pressure,
thickening of the small vessel walls occurs at the retinal
level (like other body vasculature).
❖ This thickening occurs mainly at the sites of arterio-venous
crossings of the retinal microvasculature, which leads to
arterio-venous crossing changes (that represent adaptive
mechanisms of the veins to the increased pressure and the
thickening of the arterial vessel walls).
❖ The vein is concealed by the artery, then there is deflection
of the veins and tapering of their ends at the sites of arterio-
venous crossings.
❖ In late stages, there is an increased light reflection from the
arterial wall (due to increased deposition of atherosclerotic
arterial patches), giving the arteries a whitish appearance
on fundus examination (copper and silver wiring of the
arteries).
❖ These atherosclerotic changes can denote the existence
of such changes in other blood vessels elsewhere
(cerebral or renal).

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Central Retinal Vein Occlusion (CRVO)

• It is an obstruction of the central retinal vein that occurs due to

either systemic or local (ocular) causes.
• Systemic causes:
❖ Atherosclerosis of the central retinal artery (this usually
affects the central retinal vein at the lamina cribrosa, where
the central retinal artery and vein share a common
adventitial sheath together).
❖ Systemic diseases causing microangiopathies (diabetes
mellitus, hypertension, hyperlipidemia, and renal
impairments).
❖ Systemic diseases causing hyperviscosity of the circulation
(polycythemia, leukemia, thrombocytosis, or females on
oral contraceptive pills).
❖ Systemic diseases causing phlebitis (mainly Behcet’s
disease).
• Local (ocular) causes:
❖ Glaucoma
❖ Orbital masses compressing the central retinal vein along
its course inside the optic nerve.

• Clinical picture of CRVO:

❖ Symptoms:
✓ Rapid painless drop of vision that usually occurs in
the morning on awakening (due to stagnant
circulation at night).
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 ❖ Signs:
✓ Dropped visual acuity on awakening.
✓ Relative afferent pupillary defect if severe retinal
affection occurs (in cases with marked retinal
ischemia).
✓ Fundus examination reveals dilated tortuous retinal
veins (due to blocked venous drainage by the central
retinal vein occlusion) with extensive leakage and
hemorrhages. In ischemic CRVO, cotton wool spots
are obvious.
• Complications of CRVO:
❖ Cystoid macular edema (which markedly affects vision).
❖ Neovascular glaucoma (100-day glaucoma): common in
ischemic types with liberation of vasoformative materials
from the ischemic retina.
❖ Vitreous hemorrhage and tractional retinal detachment in
ischemic types with liberation of vasoformative materials
and formation of neovessels which can easily bleed.
• Investigations of CRVO:
❖ Systemic and local work-up to rule out the causes and
prevent recurrence of attacks.
❖ Fundus Fluorescein Angiography: gives a view only after
the hemorrhage partially subsides. It shows vascular
affection and ischemic areas (retinal circulation).
❖ Optical Coherence Tomography: This also should be done
after the hemorrhage subsides. It shows macular edema.

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 • Treatment of CRVO:
❖ Treatment of the systemic and local causes is mandatory
to guard against recurrences.
❖ Intravitreal injection of anti-VEGFs is the main line of
treatment.

Branch Retinal Vein Occlusion (BRVO)

• It is an occlusion to a branch of the retinal veins, with

corresponding field defects.
• Visual acuity is affected only if the macular area is involved.
• Intravitreal injection of anti-VEGFs is the main line of treatment.

Central Retinal Artery Occlusion (CRAO)

• It is an occlusion of the central retinal artery that usually occurs

at the lamina cribrosa of the sclera.
• The major problem is that the CRA is an end artery with no
collaterals, which is why the ischemic damage to the inner retinal
layers is irreversible on its closure.
• Major Causes of CRAO:
❖ Embolic occlusion: from the heart or calcified atheromas of
an atherosclerotic carotid artery.

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 ❖ Arteritis (mainly giant cell arteritis in old age and collagen
diseases “as systemic lupus erythematosus” in young
age).
• Clinical Picture of CRAO:
❖ Symptoms:
✓ Transient attacks of vision loss (amaurosis fugax) if
an embolus occludes the CRA and is then
dislodged.
✓ Sudden painless loss of vision.
❖ Signs:
✓ Visual acuity becomes no perception of light (blind
eye).
✓ Pupil is amaurotic (no light reflex response), on the
contrary to optic nerve diseases or severe retinal
diseases which cause a relative afferent pupillary
defect (RAPD).
✓ Fundus shows a milky white retina (CRAO causes
swelling and edema of the retinal layers with
disruption of the vessel wall integrity, which is then
followed by ischemic necrosis).
✓ Fundus also shows a characteristic cherry red spot
at the fovea (as it is totally supplied by the choroid),
although the ischemic necrosis and the
accumulation of metabolites cause toxic damage to
the fovea thereafter.

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 ✓ The optic disc shows consecutive optic atrophy after
variable periods.
• Differential Diagnosis of a cherry red spot at the fovea:
✓ CRAO
✓ Commotio Retinae (edema of the retinal layers with blunt
trauma, which usually resolves spontaneously and carries
a good prognosis).
✓ Tay Sacks disease (a retinal disease that is common in
young Jewish children with deposition of abnormal retinal
metabolites).
• Investigations of CRAO:
✓ Fundus Fluorescein Angiography: it shows no arterial filling
or delayed arterial filling of the whole retinal vasculature.
• Treatment of CRAO:
✓ It is an ocular emergency.
✓ Try to dislodge the embolus by asking the patient to lie flat
and performing a firm ocular massage.
✓ Ask the patient to rebreathe into a paper bag (as
hypercapnia causes vascular dilatation and can help to
dislodge the embolus).
✓ Intravenous thrombolytic agents (such as streptokinase)
are used under cardiologist guidance.
✓ Intravenous carbonic anhydrase enzyme inhibitors can help
by reducing aqueous production.
✓ A cardiological and hematological consultation should be
performed to search for the source of artery occlusion.

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 • CRAO with a patent cilioretinal artery:
✓ In 20% of the population, there is a branch of the choroidal
circulation which supplies the papillo-macular bundle and
is known as the cilioretinal artery.
✓ The existence of this branch spares the central vision in
cases of CRAO.

Branch Retinal Artery Occlusion (BRAO)

• This manifests by fundus picture similar to CRAO but

in a retinal sector, and also there is an altitudinal field
defect that corresponds to the occluded branch.

Retinitis Pigmentosa (RP)

• It is a bilateral progressive atrophy of the

photoreceptors that primarily affects the rods and the
cones are spared until late in the disease course
(starts peripherally then gradually spreads centrally).
• It is usually inherited in an autosomal dominant
pattern, but cases that are inherited in an X-linked
recessive pattern are the most severe forms.
• Clinical picture of RP:
❖ Symptoms:
✓ Progressive night blindness (nyctalopia).
❖ Signs:
✓ Attenuated retinal arteries and arterioles.
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 ✓ Bone spicules (spider-like retinal pigment
clumps) that start in the mid-periphery then
spread more peripherally then spread centrally
in advanced cases.
✓ The color of the disc is waxy yellow (disc
pallor due to consecutive optic atrophy).
• Investigations of RP:
✓ Visual field (perimetry): progressive concentric
contraction of the field, till a tubular field
persists for a long time before central disease
progression.
✓ Electrophysiology of the retina
(Electroretinogram): shows decreased
scotopic response (in the darkness, due to
peripheral rods affection), followed by late
affection of the photopic response (in the light,
due to late affection of the central cones).
• Treatment of RP:
✓ No radical treatment is available, although
gene therapy trials are ongoing.
✓ Vitamin A supplements can help to halt the
disease progression, as it is important for
photoreceptor metabolism.
✓ Low vision aids can help patients to cope with
disease.
• Differential Diagnosis of RP:

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 ✓ Glaucoma (can also cause tubular visual field).
✓ CRAO with a patent cilioretinal artery (can also
cause tubular visual field).
✓ Siderosis bulbi with retained iron foreign bodies
(can cause dark deposits reminiscent
of bone spicules).

Retinopathy of Prematurity (ROP)

• It is a retinal pathology that develops in preterm

infants who are born before 32 weeks of gestation or
less than 1.5 kilograms in weight.
• The problem starts to develop when these preterm
infants are put in incubators with high oxygen levels,
as the oxygen releases oxygen-free radicals that
affect the normal development of the retinal vessels
in these newborns.
• The development of the retinal vasculature is
incomplete in any full-term newborn and completes
at about one month after labor. So, in preterm infants,
the development of the retinal vasculature is still
underdeveloped, and this is aggravated by the
oxygen-free radicals from the incubators.
• Not only do the toxic free radicals stop the normal
development of the retinal vasculature, but they also

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 result in the release of vasoformative materials
(VEGFs) from the damaged retina, leading to
possible hemorrhage and tractional retinal
detachment.
• Treatment of ROP:
❖ All newborns who are put in incubators should be
closely monitored for any retinal abnormalities.
❖ If the retina becomes avascular (ischemic) with
neovessel formation, LASER treatment should be
performed on the ischemic retina to inhibit the release
of VEGFs.
❖ Intravitreal anti-VEGFs can also give positive results.
❖ Vitrectomy is indicated if there is vitreous hemorrhage
and tractional retinal detachment.
N.B. ROP is a cause of leukocoria in newborns (in late stages
with tractional retinal detachment).
N.B. Monitor the newborn for possible amblyopia
development.

Age-Related Macular Degeneration (AMD)

• It is a leading cause of visual loss in old age (above

50 years) worldwide.
• Smoking is a major aggravating factor.
• Types of AMD:

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❖ Dry AMD:
✓ It is more common than its wet counterpart and
is milder in vision affection.
✓ It starts with the development of drusens, which
are accumulations of lipofuscin pigment below
the retinal pigment epithelium.
✓ Afterwards, the drusens coalesce together
forming geographical atrophic patches of the
outer retinal layers and the choroid.
✓ Patients should be advised to stop smoking to
halt the progression and to use low-vision aids.
❖ Wet (exudative) AMD:
✓ In this type of AMD, vision affection is usually
more severe than its dry counterpart.
✓ There is an abnormal choroidal neovascular
membrane (CNV) that develops between the
retina and the choroid, with abnormal leakage
of edema fluid and hemorrhage from this
membrane (which can heal by fibrosis).
✓ Visual acuity is markedly affected if the CNV
develops at the macular area.
✓ It is usually treated by intravitreal injection of
anti-VEGFs.

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Retinal Detachment (Rhegmatogenous, Tractional,
and Exudative)

Rhegmatogenous Retinal Detachment (RRD)

• In this type of RD, there is a retinal tear (rhegma). With this tear,
there must be vitreous liquefaction for an RD to develop (so that
the fluid vitreous can percolate under the retinal tear).
• Vitreous liquefaction is common with high myopia and trauma.
• The entrance of the liquified vitreous through the retinal tear
causes progressive separation of the outermost retinal layer
(retinal pigment epithelium) from the other nine retinal layers
(neurosensory retina).
• The retinal pigment epithelium is always firmly adherent to the
choroid, so separation by fluid occurs between it and the other
nine retinal layers.
• The retinal tears are usually horseshoe but maybe giant if
involving more than three retinal clock hours or maybe minute
holes (especially with high myopes having degenerated
peripheral retinae).
• Clinical picture of rhegmatogenous RD:
❖ Symptoms:
✓ Musca volitans (a moving dark musca
corresponding to the retinal tear is seen in front of
the patient, as the retinal tear casts its shadow on
the photoreceptors).

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 ✓ Flashes of light in dark places (due to
photoreceptors irritation by the vitreous fluid).
✓ A black curtain in front of the corresponding field (if
retinal detachment occurs with the entrance of the
separating vitreous fluid through the retinal tear).
❖ Signs:
✓ Variable affection of vision (mainly severe if the
macula is involved. If the macula is still attached
“macula on”, there is a corresponding visual field
defect to the area of retinal detachment).
✓ The pupil shows a RAPD if the RD is extensive.
✓ Fundus examination shows the retinal break, where
the choroid appears dark red below the area of the
break.
✓ Fundus examination reveals the RD as a greyish-
white retinal elevation corresponding to the retinal
tear location.
• Treatment of rhegmatogenous RD:
✓ If there is an RD and the macula is still on, it needs an
urgent surgical intervention to save the macula.
✓ If there is a retinal break without detachment, a double row
of LASER treatment is applied around the whole tear (to
create chorioretinal scarring and seal the tear, hence
preventing the entrance of fluid vitreous below it and
preventing the development of RD).

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✓ If there is a break with RD, two surgical modalities are
available:
1- Retinal buckle:
o Drainage of any subretinal fluid is first
performed.
o This is followed by endo LASER around the
retinal tear or cryo from the outside.
o The sclera is then indented from the outside by
a buckle at the site of the retinal break (to
tamponade the retina from the outside).
2- Vitrectomy with endo LASER and silicon oil
injection:
o In some giant or multiple tears, the buckle cannot
be fit over the break(s).
o The vitreous is removed by vitrectomy surgery,
and then the subretinal fluid is drained from
underneath the retina.
o This is followed by endo LASER around the retinal
tear.
o Then silicon oil is injected into the vitreous cavity
(as an alternative to the buckle that should have
been fit from outside).
o The silicon oil should be kept for a variable period
inside the eye to have a tamponading effect on the
retina, but it should be removed after a maximum
period of six months.

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 o Complications of long-standing silicon oil:
✓ Corneal band keratopathy.
✓ Emulsification of silicon oil and percolation
into the anterior chamber, forming an
inverted hypopyon.
✓ Secondary glaucoma due to blocking the
angle by silicon.
✓ Secondary cataract by the silicon damaging
effect on the crystalline lens.
o Some surgeons usually prefer vitrectomy over
buckle surgery.

Tractional RD

• It is a type of RD where there are no retinal tears, but the retina

is rather pulled by fibrosis inside the vitreous cavity.
• This is common with organized vitreous hemorrhage following
trauma or any causes of retinal ischemia with neovessel
formation (mainly proliferative diabetic retinopathy and ischemic
CRVO).
• The retina is concave in shape and corrugated by the pulling
fibrous membranes of the vitreous, with limited retinal mobility.
• Treatment is by vitrectomy with removal of the fibrotic vitreous
membranes.

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Exudative RD

• In this type of RD, there are also no retinal tears, but the retina is
rather pushed by choroidal lesions.
• This is common with choroiditis or choroidal masses that push
the retina and is also common with pre-eclampsia and eclampsia
that cause significant choroidal effusions.
• The retina is convex and smooth with a high elevation and
shifting fluid with changing of the patient’s position.
• Treatment mainly involves treatment of the cause.

Orbit
Anatomy of the Orbit:

• The orbit is the bony cavity that encloses the globe.

• It is pyramidal, with the apex at the optic foramen and the base
at the orbital margin.
• The ratio of the volume of the orbit to that of the globe is 4.5:1,
meaning that the globe is not incarcerated in the orbital cavity,
which is protective to the globe in cases of trauma. Furthermore,
this empty orbital space around the globe is filled with orbital
tissue (mainly in the form of orbital fat), which is a cushion-like
tissue that acts as a shock absorber.

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• There are four orbital walls, namely the roof, floor, medial, and
lateral walls:
❖ The roof is formed of the frontal bone and the lesser wing
of the sphenoid bone.
❖ The floor is mainly formed of the zygomatic bone and the
maxillary bone.
❖ The medial wall is formed of part of the maxillary bone,
lacrimal bone, ethmoid bone, and body of sphenoid bone
❖ The lateral wall is formed of the zygomatic bone and the
greater wing of the sphenoid bone.
• The most vulnerable part of the globe to blunt trauma is the lower
lateral part. However, this bony part (the zygoma) is the strongest
part of the orbit. Hence, when it is exposed to blunt trauma, it is
not the commonest bone to be fractured, but the maxillary bone
is the most commonly fractured one.
• Although the part of the ethmoidal bone in the orbital cavity is
perforated by the ethmoidal air sinuses, it is not the weakest
orbital bone. This is because the air sinuses create a honeycomb
pattern within the bone that gives it relative strength.
• The optic foramen lies at the apex of the orbit and both the optic
nerve and ophthalmic artery pass through it, where the optic
nerve leaves the orbit through the optic foramen to reach the
middle cranial fossa through the optic canal where it joins the
optic chiasma.
• The superior orbital fissure is one of the main orbital fissures that
lies between the lesser and greater wings of the sphenoid bone.

136
 Many important orbital structures pass through it, including the
branches of the ophthalmic nerve, the cranial nerves supplying
the extraocular muscles (namely oculomotor, trochlear, and
abducens nerve), and the superior and inferior ophthalmic veins
that receive the venous drainage of the whole globe and orbital
tissues.
• The orbital contents can be summarized as follows:
❖ The globe.
❖ The ocular adnexa (lid, conjunctiva, and lacrimal system).
❖ The extraocular muscles (forming the muscle cone
enclosing the optic nerve).
❖ Orbital vessels and nerves.
❖ Fat in between the orbital structures (resembling grains of
corn and acting as a shock absorber).

Diseases of the Orbit:

Acute Orbital Cellulitis

Thyroid Ophthalmopathy
Cavernous Sinus Thrombosis
Differential diagnosis of Proptosis
Work up for a case of proptosis
Enophthalmos

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 Acute Orbital Cellulitis
• It is an acute inflammation of the orbital soft tissues (mainly
fat), which may be caused by bacterial or less commonly
fungal infections (in immunosuppressed individuals like
those on long-term steroids, chemotherapy, diabetic
ketoacidosis, and chronic renal failure).
• Causes:
❖ Extension from preseptal cellulitis of the eyelid
(mainly in extremes of age and immunosuppressed
individuals).
❖ Extension from neighboring sinuses (mainly
ethmoidal sinusitis, and also from maxillary sinusitis
or dental problems extending to the orbit through the
maxillary sinus).
❖ Introduction of infection from penetrating trauma or
contaminated extraocular surgeries (mainly squint
surgeries).
❖ Recently, some COVID-19 patients developed fungal
mucormycosis of the orbit, where most of these
patients were immunosuppressed.

• Clinical picture:
❖ Symptoms:

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 ✓ General symptoms of fever and malaise are
uncommon due to the relatively small surface area
of the orbit in relation to the whole body.
✓ Pain (compression on ciliary nerves by inflammatory
masses).
✓ Redness (mainly due to blocked orbital venous
drainage through the ophthalmic veins by
inflammatory masses).
✓ Drop of vision (marked visual affection comes late
with optic nerve compression).
✓ Eye swelling or bulging (the globe bulges out due to
pressure by the inflammatory masses).
✓ Double vision (due to affected extraocular muscles
or their nerve supply in one eye only, so the images
from both eyes fall on non-corresponding retinal
points).
❖ Signs:
✓ Tenderness.
✓ Edema and congestion of the eyelid skin (lid
puffiness due to blocked venous drainage).
✓ Conjunctival chemosis and congestion (due to
venous congestion).
✓ Drop of visual acuity.
✓ Axial proptosis.

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 ✓ Diplopia and affected ocular motility
(ophthalmoplegia due to compression of the
extraocular muscles or their supplying nerves).

N.B. The commonest cause of unilateral or bilateral proptosis

in a child is orbital cellulitis.

• Clinical differentiation from preseptal cellulitis:

❖ Orbital cellulitis may externally resemble preseptal
cellulitis, but it can be differentiated by the existence of one
or more of the following in case of orbital cellulitis:
✓ Affection of vision (due to optic nerve affection which
is a late presentation).
✓ Color vision affection (due to affection of color with
optic nerve compression, which is for red/green
colors and presents earlier than a drop of vision in
case of optic nerve compression due to the
superficial location of the fibers responsible for color
perception).
✓ Pupillary light reflex affection (this is also affected
earlier than vision affection due to the superficial
location of fibers responsible for the afferent
pupillary reflex within the fibers of the optic nerve).
✓ Ocular motility affection (due to compromise of the
extraocular muscles or their nerves within the
inflamed orbital cavity).

140
 ✓ Ocular congestion (due to blocking the venous
drainage through the superior and inferior
ophthalmic veins, as they are usually compressed
within the orbital cavity by the existence of
inflammatory masses).
✓ Proptosis (an important differentiating sign, but it is
a late presentation except in severe conditions that
start with early proptosis).

• Sequelae of orbital cellulitis:

❖ Cure: with early and proper management.
❖ Orbital abscess formation: if the condition was
neglected or improperly managed where a blind painful
eye is the end result.
❖ Progression into complications:
✓ The most common complication (in any orbital
disease that causes proptosis) is exposure
keratopathy, and the most serious is compressive
optic neuropathy.
✓ Extension of the infection to the globe causing
panophthalmitis.
✓ Extension of infection along the superior and inferior
ophthalmic veins to the cavernous sinus causing
cavernous sinus thrombosis.
✓ Compression of the central retinal vein and the
central retinal artery (their portions that pass within

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 the substance of the optic nerve) causing vascular
occlusions.
✓ Compression of the optic nerve fibers, resulting in
the affection of color vision and pupillary light reflex,
followed by a drop of vision at later stages. If
compressive optic neuropathy is left untreated, optic
atrophy ensues after variable periods (depending on
the severity of compression and optic nerve fibers
viability).
• Management of a case of acute orbital cellulitis:
❖ Hospitalization is preferred (especially if the patient cannot
come for regular follow-up and close monitoring of this
serious condition).
❖ Systemic antibiotics (intravenous or intramuscular) should
be initiated as soon as possible, where a combination of
vancomycin (for gram-positive organisms), cephalosporin
(for gram-negative organisms), and metronidazole (for
anaerobes as the orbit is a closed space) should be
prescribed.
❖ A CT scan of the orbit and paranasal sinuses should be
ordered, especially in cases that are not responding to
treatment. One of the main reasons to order for CT scan
in such cases is to exclude that the orbital cellulitis may be
a masquerade syndrome for an intraocular tumor (as
retinoblastoma in children).

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 ❖ Examine the patient for progression or regression of the
clinical signs every four hours (close monitoring reduces
the risk of complications).
❖ ENT and neurosurgical consultation if sinusitis or
cavernous sinus thrombosis are suspected, respectively.

Thyroid Ophthalmopathy (Endocrine

Exophthalmos)
• It represents orbital changes that occur due to thyroid
dysfunction (hyper, hypo, or even euthyroidism “can precede
chemical thyroid dysfunction”).
• Thyroid ophthalmopathy is not always related to the severity of
chemical thyroid conditions.
• In patients with thyroid dysfunction, 25-50% of them will develop
thyroid ophthalmopathy and only 5% will develop severe or
vision-threatening manifestations.
• Pathogenesis:
❖ It is a type II hypersensitivity reaction to TSH receptors in
the thyroid gland.
❖ At the level of the orbit, autoantibodies (Thyroid-
stimulating immunoglobulins) are found attached to the
TSH receptors that are found on the orbital fibroblasts or
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 fibrocytes. This leads to cytokines release that causes
abnormal deposition of inflammatory cellular infiltrates and
glycosaminoglycans.
❖ These abnormal cells and glycosaminoglycans are
deposited in the orbital tissue, the extraocular muscles,
and the eyelids. As these molecules have a high osmotic
pressure, they imbibe fluids from the surrounding tissues
and vessels, leading to increased volume and pressure
inside the orbit and within the extraocular muscles.
❖ Failure of good control of this autoimmune reaction leads
to the development of post-inflammatory fibrosis that
affects the orbital tissue, the extraocular muscles, and the
eyelids.
❖ The disease thus passes into two stages:
✓ Active stage: where the autoimmune inflammatory
reaction is ongoing with affection to the venous
drainage of the whole orbit, globe, and eyelids
(compression of the ophthalmic veins). This leads to
soft tissue signs.
✓ Quiescent stage: where the reaction subsides, but
improper management leads to fibrotic tissue
deposition within the orbit, the extraocular muscles,
and the eyelids, leading to the stage of restrictive
ocular motility and lid fibrosis and retraction.

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Graves’ Disease
• It is the autoimmune hyperthyroidism that usually presents in
young to middle-aged females, and it is the commonest cause
of unilateral or bilateral proptosis in adults.
• Clinical picture:
❖ Symptoms:
✓ General symptoms: it mainly presents with
nervousness and irritability, heat intolerance, weight
loss with increased appetite, and palpitations.
Oligomenorrhea may develop in some cases.
✓ Local symptoms: it mainly presents with eye
protrusion (causing cosmetic disturbance), eye
redness and edema (during the active stage), and
double vision (during the active stage or more
commonly during the fibrotic stage with restricted
ocular motility, that is unilateral or bilateral
asymmetrical).
❖ Signs:
✓ General signs: it usually presents with an enlarged
thyroid gland (goiter), tachycardia, and hand
tremors. If such signs are absent, euthyroid Graves’
or Ophthalmic Graves’ is diagnosed.
✓ Local signs:

1- Soft Tissue Signs

2- Lid Signs

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3- Restricted Ocular Motility

4- Proptosis

1- Soft tissue signs:

❖ These are signs of disease activity, where there
is an acute orbital edema that compresses the
superior and inferior ophthalmic veins, hence
blocking the venous drainage.
❖ This is mainly manifested by lid edema,
conjunctival chemosis, and conjunctival
congestion.
2- Lid signs:
❖ They are caused by two factors:
✓ Muller muscle overaction (due to
sympathetic overactivity with
hyperthyroidism).
✓ Lid fibrosis during the quiescent phase.
❖ Lid signs include:
✓ Staring look.
✓ Von Graef’s sign (lid Lag on downgaze).
✓ Dalrymple’s sign (scleral show).
✓ Stellwag’s sign (infrequent blinking).
3- Restricted ocular motility:

146
 ❖ This is mainly during the quiescent phase (with
fibrosis) more than during the active phase
(with edema and congestion).
❖ The inferior rectus muscle is the most affected
muscle by Graves’ disease. Hence, the
upgaze is the most affected gaze (due to
fibrosis during the quiescent phase that limits
ocular motility in the opposite direction of
action of a muscle, on the contrary to edema
during the active phase that limits ocular
motility in the same direction of muscle action).
4- Proptosis:
❖ Thyroid ophthalmopathy is the most common cause of
unilateral or bilateral proptosis in an adult (especially
females).
❖ Proptosis results from pushing the globe forward by the
abnormal autoimmune depositions in the active phase or
the fibrotic proliferation in the quiescent phase.

• Complications of Graves’ disease:

❖ The most common complication is exposure keratopathy
(due to proptosis that leads to improper covering of the
eyelids to the whole cornea in a proptotic globe).
❖ The most serious complication is compressive optic
neuropathy (due to a compressed optic nerve or its blood

147
 supply by proptosis, where the color and pupillary light
reflex are affected first followed by the visual acuity).
N.B. These are the complications of any case of proptosis
(especially with more prolonged durations) and not only proptosis
due to Graves’ disease.

• Investigations for thyroid ophthalmopathy:

❖ Free T3, free T4, and TSH hormonal profile.
❖ CT scan (to detect orbital and muscle affection).

• Treatment of thyroid ophthalmopathy:

❖ General measures:
✓ Stop smoking (as it aggravates any autoimmune
disease).
✓ Systemic antithyroid drugs (mainly alleviates lid
retraction due to muller muscle overaction with
sympathetic hyperactivity).
❖ Local signs management:
✓ Soft tissue signs: use topical lubricants and
steroids (if needed) to reduce the inflammatory
irritation and congestion.
✓ Lid signs: systemic antithyroid drugs will reduce lid
retraction due to sympathetic hyperactivity reaching
to muller muscle, while any lid fibrosis will not be
affected by the systemic antithyroid treatment and
requires recession of the fibrosed lid muscles (if

148
 cosmetically unpleasant with a stable disease for 6
months).
✓ Restricted ocular motility: it requires recession of
the fibrosed one or more extraocular muscles (if it is
a significant restriction causing diplopia in the
primary or reading position and the disease should
be stable for 6 months).
✓ Proptosis: high dose steroids are used systemically
in the active phase, while in the quiescent phase they
are of no value, and orbital decompression is
required (iatrogenic fractures in one or more orbital
walls to relieve orbital compression, hence reducing
the cosmetic disfigurement of proptosis and also
reduces optic nerve compression).
❖ Management of complications:
✓ Exposure keratopathy: frequent lubricants are
highly recommended. If the condition is not controlled
by lubricants, an amniotic membrane graft or
tarsorrhaphy can be surgically performed.
✓ Compressive optic neuropathy: it is treated by
pulsed steroids therapy, where 1000 mg of steroids
are given intravenously for 3 successive days (in the
cardiac care unit to monitor the patient for possible
development of ventricular tachycardia and
fibrillations). This is followed by ten days of full-dose

149
 oral steroids (60 mg per day) with gradual tapering
thereafter.

N.B. Orbital decompression can be performed for:

✓ Quiescent cases of proptosis.

✓ Intractable compressive optic neuropathy (not responding
to pulsed steroids).

N.B. Thyroid-induced glaucoma can occur due to compression of

the vortex veins or episcleral veins along their path in the sclera (due
to proptosis).

Cavernous Sinus Thrombosis

• The cavernous sinus is a venous channel that drains the face,
the paranasal sinuses, the middle ear, and the orbit.
Furthermore, the subcutaneous tissue behind the ear is drained
by the cavernous sinuses and this has an important clinical
implication to diagnose the sinus thrombosis.
• The cavernous sinuses are two venous channels that are located
on both sides of the body of the sphenoid bone (beside the Sella
turcica where the pituitary gland lies). Both sinuses are
connected through emissary veins that pass through the body of
the sphenoid bone. Hence, infection and thrombotic changes can
spread through these emissary veins from one sinus to the other.
• Structures passing through the cavernous sinus:

150
 ❖ Within the substance of the sinus: abducens nerve and
internal carotid artery.
❖ Structures in the lateral wall of the sinus: Oculomotor
nerve, trochlear nerve, and ophthalmic nerve.
• Main routes of infection to the cavernous sinus:
❖ Orbital cellulitis.
❖ Acute dacryocystitis.
❖ Panophthalmitis.
❖ Face infections (acne vulgaris in the dangerous zone of
the face).
❖ Other cavernous sinus affection.
• Clinical picture of cavernous sinus thrombosis:
❖ Symptoms
✓ General: fever, malaise, delirium, or coma are
associated with meningitis or meningoencephalitis
that may complicate the condition (as the cavernous
sinus covering is a fold of dura matter).
✓ Ocular:
▪ Pain (dura matter is sensitive to pain, so there
is a headache with referred ocular pain due to
compression of the dural covering of the sinus
when it enlarges with thrombosis).
▪ Redness and edema (cavernous sinus
thrombosis affects the venous drainage of the
whole globe and orbit that drains in the

151
 cavernous sinus through the superior and
inferior ophthalmic veins).
▪ Drop of vision (visual pathway compression,
as the termination of the optic nerve and the
optic chiasm lie very close to the cavernous
sinuses).
▪ Double vision (as the nerves supplying the
extraocular muscles all pass through the
cavernous sinus).
▪ Eye bulging (due to blocking the orbital venous
drainage).
❖ Signs:
✓ Tenderness.
✓ Marked congestion of conjunctival and episcleral
vessels.
✓ Dropped visual acuity.
✓ Diplopia and limited ocular motility.
✓ Increasing axial proptosis.
✓ Edema of the mastoid region behind the ear
(emissary vein passes from this area to the
cavernous sinus).
✓ Other cavernous sinus affection is mainly detected
by abducens nerve affection and then other signs
follow (as it is an exposed nerve within the
substance of the sinus). Abducens nerve affection is
mainly manifested by diplopia and esotropia.

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 ❖ Complications:
✓ Like any condition causing proptosis, the most
common complication is exposure keratopathy and
the most serious is compressive optic neuropathy.
❖ Management:
✓ Hospitalize the patient.
✓ Reassure the diagnosis by clinical signs together
with a CT scan with contrast or MRI.
✓ Intravenous broad-spectrum antibiotics.
✓ Intravenous heparin for thrombosis.
✓ Management of the complications (see before).

Differential Diagnosis of Proptosis

❖ Causes of pseudo proptosis (there is no mass pushing
the globe, so there is no true proptosis, but it is an
apparent proptosis):
1- High axial myopia: where the globe is abnormally
elongated.
2- Craniosynostosis: where there is an abnormal
premature closure of one or more of the skull sutures,
which affects the normal development of the orbital
bones and leads to a shallow orbit, giving a false
impression of apparent proptosis due to the disturbed
ratio between the orbit and the globe volumes.
3- Lid retraction of the same side.

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 4- Lid ptosis of the other side.

❖ Causes of true proptosis:

1- The commonest cause in children is orbital cellulitis and
in adults is thyroid ophthalmopathy.
2- Tumors (as optic nerve tumors, orbital metastasis,
lymphomas, and lacrimal gland tumors).
3- Trauma (as it leads to hemorrhage and edema
formation in the orbit pushing the globe).
4- Vascular causes (such as cavernous sinus
thrombosis).
5- Inflammatory causes (such as orbital cellulitis).

N.B. Optic nerve tumors (such as glioma and meningioma) usually

affect vision earlier than other causes of proptosis, as the mass directly
compresses the optic nerve.

N.B. Lacrimal gland tumors (as pleomorphic adenomas or sarcoidosis)

cause non-axial rather than axial proptosis, as the gland enlarges
pushing the globe downwards and medially.

Work up for a Case of Proptosis

• Proper history taking.
• Examination:
154
 ❖ Exclude pseudo proptosis.
❖ Measure the degree of proptosis (using a transparent ruler
or Hertel’s Exophthalmometer).
❖ Evaluate the ocular motility affection.
❖ Examine the optic nerve functions for possible optic nerve
compression (mainly color vision and pupillary light reflex
as they are affected early).
❖ Slit lamp examination (mainly to exclude exposure
keratopathy).

Enophthalmos
• It is the retraction of the globe inside the orbit.
• Causes:
❖ Involutional (fat atrophy).
❖ Post-inflammatoryy fibrosis.
❖ Scirrhous cancer breast.
❖ Blow-out orbital fracture:
✓ It usually occurs inferiorly at the infraorbital
canal.
✓ Signs:
▪ Enophthalmos.
▪ Hypotropia with limited up gaze and
vertical diplopia (this indicates
entrapped inferior rectus muscle in the
fracture, which causes oculocardiac
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 reflex “bradycardia” and is known as
trapdoor fracture).
▪ Infraorbital anesthesia (infraorbital nerve
injury).
✓ Investigations:
▪ CT Scan: Teardrop sign and evidence of
the site of fracture at the inferior orbital
wall.
✓ Treatment:
▪ Prophylactic antibiotics.
▪ Avoid nasal blowing (to avoid surgical
emphysema).
▪ Surgical repair is indicated if:
o Enophthalmos more than 2 mm.
o Large fracture of more than 2 cm.
o Diplopia in primary or reading
position.
o Trapdoor fracture (muscle entrapment
leading to bradycardia with
oculocardiac reflex).

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 Errors of Refraction

Optics of the Visual System:

• There are two major optical systems in the eye, namely the
cornea and the crystalline lens.
• The cornea shares by 42-43 diopters of the visual system's
optical power, and it is fixed in value.
• On the other hand, the crystalline lens shares by 16-17 diopters
while looking at a distant object (equal to or further than 6
meters), and this power is continuously adjusted along the day
by the accommodation system (the effect of the circular portion
of the ciliary muscle through the suspensory ligaments).
• To obtain a sharp visual acuity, the image of any object must be
focused on the retina. This is known as emmetropia.
• In ametropia, the image is not focused on the retina, with a
blurred image.

Errors of Refraction:

Myopia
Hypermetropia
Astigmatism
Presbyopia

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Myopia (Near-Sightedness)
• In this refractive error (ametropia), the image is focused in
front of the retina (while there is no near target for
accommodation).
• Types of myopia:
1- Refractive Myopia (abnormal power of the visual system)
✓ Curvature myopia (keratoconus or less commonly
lenticonus).
✓ Lenticular Index myopia (nuclear sclerosis “second sight”
or hyperglycemia).
✓ Lenticular dislocation myopia (anterior dislocation leads
to myopic shift).

2- Axial Myopia (abnormally long axial length of the globe)

✓ It is the commonest type of myopia.

✓ Genetic elements and prolonged near activities are
highly associated with myopia progression.
✓ Normal axial length in adults is about 24 mm
(measured by A-scan ultrasound).
✓ Each 1 mm increase in the axial length leads to 3
Diopters increase in the refractive power.
✓ Axial myopia could be simple, degenerative
(pathological or high myopia), or congenital:
▪ Simple myopia arises late in childhood or
around puberty and is stationary around the age
of 25.

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 ▪ Degenerative myopia starts in early childhood
and can progress beyond the age of 25.
▪ Congenital myopia is uncommon and is usually
stationary.

• Clinical picture of myopia:

❖ Symptoms:
✓ Blurred far vision (that is why it is named near-
sightedness).
✓ Screwing of the eye (pinhole effect negates
aberrations and scattering).
✓ Muscular asthenopia (due to
accommodation/convergence dissociation, where
the myopic patient does not need to exert
accommodation “as he already has a long axial
length or a high power”, so there is no associated
accommodative convergence. But if the patient looks
at a near target, he must perform convergence to
avoid diplopia, but it is not the usual accommodative
convergence and it is rather a fusional convergence
that causes muscular asthenopia).
❖ Symptoms of degenerative myopia:
✓ Musca Volitans (vitreous floaters that develop due to
vitreous liquefaction).
✓ Decreased night vision (due to degenerated
peripheral retina).

159
 ✓ Symptoms of complications (such as fuch’s spot that
affects central vision at the fovea).
❖ Signs of myopia:
✓ Retinoscopy or Autorefractometer: can show the
degree of myopia in numerical values (retinoscopy is
mainly used for uncooperative children, and after
retinoscopy or autorefractometry, subjective trial of
refraction is mandatory for refinement of the
refractive correction as per patient’s satisfaction).
✓ Signs of Degenerative Myopia:
▪ Pseudo-proptosis.
▪ Deep anterior chamber and tremulous iris.
▪ Fundus may show:
o Vitreous liquefaction.
o Tessellated (tigroid fundus, due to stretching of
the retina with the elongated globe, so the
underlying choroidal vessels are more
obviously seen with visualization of the
underlying choroidal pigmentation and retinal
pigment epithelium).
o Temporal myopic crescent (it is a whitish
crescent seen at the temporal margin of the
optic disc due to the absence of choroid and
retina at the disc edge with globe elongation,
so the underlying sclera is seen as a whitish
crescent).

160
 o Patches of chorioretinal atrophy can be seen
with obvious choroidal vessels.
o Lattice degeneration and holes in the
peripheral retina.
o Macular hole may develop with retinal
stretching (with any anteroposterior traction).
o Posterior staphyloma (due to elongated globe,
and retrobulbar anesthesia should be avoided
to avoid globe perforation).
o Lacquer cracks are sometimes evident, which
represent cracks in the choroid with its
stretching, which may predispose to choroidal
neovascular membranes (myopic CNV). This
CNV may cause hemorrhage and fibrosis
which markedly affects vision if central in
location.
o Fuch’s spot at the fovea (usually caused by
CNV at the fovea which causes hemorrhage
complicated by fibrosis and pigmentation. It
has a poor visual prognosis).
❖ Complications of degenerative myopia:
✓ Associated cataract.
✓ Associated glaucoma (due to concurrent trabecular
sclerosis in some cases).
✓ Divergent squint (exophoria and later exotropia, as
the patient does not need to perform

161
 accommodation, so there is no associated
accommodative convergence, and hence the medial
rectus is not frequently contracting, and the lateral
rectus takes the upper hand).
✓ Retinal complications: mainly CNV and fuch’s spot,
and also retinal tears with minor traumas.

N.B. An eye with degenerative (high) myopia is considered a fragile

eye (trauma and contact sports should be avoided to reduce the
risk of complications, especially the retinal ones).

• Treatment of myopia:
❖ Concave (minus, diverging) lenses:
✓ These may be used in the form of medical glasses or
contact lenses.
✓ Contact lenses provide a wider field and need a lower
power of correction than the corresponding glasses
for the same refractive error, as the contact lenses
are nearer to the seat of ametropia than the glasses.
❖ Surgical correction:
✓ LASIK (can correct up to -10 Diopters of myopia and
is a flap-based technique with no post-operative pain
and rapid visual rehabilitation. However, the flap
needs avoidance of contact sports for variable time
intervals).

162
 ✓ Surface ablation (can correct up to -4 Diopters of
myopia, and it is a flapless technique, so it is a better
suit for athletes practicing contact sports who want a
rapid recovery to resume their sports. However,
some postoperative pain is experienced due to
exposed nerve ending with corneal epithelial removal
during surgery. It lasts for very few days).
✓ Femto LASIK is now performed for better precision
(but it is mainly needed for myopia with associated
astigmatism and aberrations).
✓ Femto SMILE is a technique that removes a stromal
wedge without either a flap creation or epithelial
removal. However, post-operative visual accuracy is
sometimes unsatisfactory for some candidates.

Hypermetropia (Far-Sightedness)
• It is a refractive error (ametropia) in which the focus of an object
is formed behind the retina (while there is no near target for
accommodation).
• Types of hypermetropia:
1- Refractive hypermetropia:
✓ Curvature hypermetropia (Cornea plana).
✓ Lenticular index hypermetropia (Cortical cataract,
Hypoglycemia).

163
 ✓ Lenticular dislocation hypermetropia (in cases of posterior
lens dislocation).
2- Axial hypermetropia:
✓ Each 1mm decrease in the axial length causes a decrease
of 3 Diopters in the eye refractive power.

• Components of hypermetropia:
❖ Total hypermetropia: it is the hypermetropic element
under complete cycloplegia (ciliary muscle paralysis).
❖ Latent hypermetropia: it is the hypermetropia that is
compensated by the tone of the ciliary muscle.
❖ Manifest hypermetropia: it is the hypermetropia that is
not compensated by the ciliary muscle tone, and it depends
on the degree of accommodative power to compensate for
it.

• Symptoms of hypermetropia:

❖ May be asymptomatic (if it is compensated for by the ciliary

muscle tone and accommodation, and in children it is
usually compensated for till high degrees due to the high
accommodative reserve).

❖ Accommodative asthenopia (as the hypermetropic patient

performs a lot of accommodation, even when seeing far
objects further than 6 meters, due to his weak refractive
power. Thus, the patient performs more accommodative

164
 convergence as synkinesis with accommodation, so there
is an accommodative asthenopia).

❖ Blurred near more than far vision (as seeing a near target
requires more refractive power).

❖ Early presbyopia (as the patient consumes his

accommodative reserve by exerting a lot of
accommodation to compensate for hypermetropia).

• Signs of hypermetropia:
❖ Retinoscopy and Autorefractometer: they show the
degree of hypermetropia.
❖ High axial hypermetropia:
✓ Small globe (by A-Scan ultrasound).
✓ Shallow anterior chamber and narrow-angle (can
predispose to angle closure glaucoma).
✓ Fundus:
▪ Obliterated or crowded optic cup, simulating disc
edema (known as pseudo papilledema), with retinal
folds and tortuous vessels emanating from the optic
disc.

• Complications of hypermetropia:
❖ Predisposition to angle closure glaucoma with increasing
age (due to superimposed lenticular enlargement with
nuclear sclerosis).
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 ❖ Convergent squint (esophoria which can progress to
esotropia, as the patient performs a lot of accommodation
and hence a lot of accommodative convergence, so the
medial rectus takes the upper hand over the lateral rectus
with more use of it).

• Treatment of hypermetropia:
❖ Convex (plus, converging) lenses.
❖ Surgical correction:
✓ LASIK (can correct up to +5 Diopters of
hypermetropia).
✓ Surface ablation can also be performed.
✓ Femto LASIK is now performed for better precision
(but it is mainly needed for associated astigmatism
and aberrations).
✓ Femto SMILE cannot be performed for
hypermetropia.

Astigmatism
• It is a refractive condition in which there is no single point
focus of an object on the retina, but there are rather
multiple points at different levels, leading to a blurred
image.
• It occurs due to different corneal powers at different
meridians or along the same meridian.

166
• Types of astigmatism:
1- Regular astigmatism:
❖ two principal meridians are perpendicular to each
other, where one has the highest power and the
other has the lowest power, with a gradual change
of power between them, but the power is the same
along the same meridian.
❖ Causes of regular astigmatism:
✓ Corneal astigmatism (physiological 0.25-
0.5 Diopters, or corneal stitches).
✓ Lenticular astigmatism (subluxated lens).
❖ The worst type of astigmatism is the mixed type,
where one of the two principal meridians is
hyperopic and the other is myopic, with maximal
image blurring.
❖ Types of regular astigmatism:
✓ With the rule (where the vertical meridian is
more myopic).
✓ Against the rule (where the horizontal
meridian is more myopic).
❖ Symptoms of regular astigmatism:
✓ Blurred vision and distorted images.
❖ Signs of regular astigmatism:
✓ The patient can read some letters and miss
others on the same chart line of visual acuity
charts.

167
 ✓ Retinoscopy and Autorefractometer show
the astigmatic refractive error.
❖ Treatment of regular astigmatism:
✓ Cylindrical lenses, where the axis of the lens
should be placed perpendicular to the
desired meridian to be corrected (in medical
glasses or contact lenses “known as toric
contact lenses).
✓ LASIK and Femto LASIK.

2- Irregular astigmatism:
❖ There aren’t two principal meridians with the
highest and lowest power, and there is no gradual
change of power along the corneal meridians.
❖ Causes of irregular astigmatism:
✓ Dense corneal scars (Leukomas).
✓ Keratoconus.
✓ Post LASIK corneal ectasia (with improper
choice of the LASIK candidates or when
performing LASIK on a cornea with early
keratoconus).
❖ Symptoms of irregular astigmatism:
✓ Marked blurring and image distortion.
❖ Signs of irregular astigmatism:
✓ Retinoscopy shows scissoring or spinning of
the red reflex.

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 ✓ Autorefractometer may not give readings due
to marked corneal distortion.
✓ Slit lamp examination shows the corneal
pathology (mainly dense scars).
✓ Corneal topography/tomography (as
Pentacam) shows the hot “red” spot of
keratoconus.
❖ Treatment of irregular astigmatism:
✓ Treatment of scars is usually by lamellar or
penetrating keratoplasty according to their
depth.
✓ Treatment of keratoconus is done by cross-
linking, intracorneal rings, or keratoplasty “in
severe cases and with dense scars”.

Presbyopia
• It refers to the recession of the near point of vision beyond
the comfortable distance (the nearest point to the eye
where the image can be focused).
• Presbyopia develops due to affection of lens pliability,
capsule elasticity, and/or ciliary muscle range of action.
• Physiological presbyopia usually arises around the age of
40-45 years and progresses thereafter.
• Contrarily, pathological presbyopia can develop earlier if:

169
 ❖ There is an exhaustion of the accommodation
components (the ciliary body and the crystalline
lens), as in cases of uncorrected hypermetropia.
❖ Glaucoma that affects the aqueous circulation
(which is the main source of nourishment and
washing away the metabolites from the crystalline
lens).

• Symptoms of presbyopia:
❖ Blurred near vision.
❖ Recession of the near point beyond the comfortable
distance for reading.

• Treatment of presbyopia:
❖ Convex (plus, converging) lenses for near vision
(they should be added to the far vision correction).
❖ Bifocal glasses to incorporate both the distance and
near vision correction together (now multifocal
glasses are also available with the addition of
intermediate distance zones).
❖ Presbyopic LASIK to correct far and near vision
simultaneously.
❖ Multifocal IOLs if there is an associated cataract, so
the cataract is removed with the implantation of a
multifocal IOL for seeing near, intermediate, and far
objects clearly.

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 Strabismus (Squint)

Applied Anatomy and Physiology:

• The extraocular muscles play an important role in keeping both

eyes aligned and hence maintaining the two visual axes parallel
to attain binocular single vision while using both eyes.
• Failure or defect to maintain the two visual axes aligned and
parallel results in strabismus (squint).
• There are six extraocular muscles in each eye, namely four recti
and two oblique muscles:
❖ A pair of horizontal recti (medial rectus and lateral rectus).
❖ A pair of vertical recti (superior rectus and inferior rectus).
❖ A pair of obliques (superior oblique and inferior oblique).
❖ Recti muscles:
✓ Origin: all recti muscles arise from the "annulus of Zinn" in
a circular fashion surrounding the optic foramen and part
of the superior orbital fissure.
✓ Insertion: all recti muscles are inserted into the sclera at
variable distances of 5.5 mm (MR), 6.5 mm (IR), 6.9 (LR),
and 7.7 mm (SR) from the limbus.
❖ Oblique muscles:
Superior oblique muscle:
✓ Origin: it arises at the optic foramen and passes along the
medial wall of the orbit to reach the trochlea, where it is
converted into a tendon.

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 ✓ Insertion: the muscle tendon is inserted into the superior
temporal quadrant of the sclera posteriorly behind the
equator (which is 14 mm behind the limbus).
Inferior oblique muscle:
✓ Origin: it is the shortest of extraocular muscles and arises
from the lacrimal fossa medially.
✓ Insertion: it is inserted in the inferior temporal quadrant of
the sclera posteriorly behind the equator.
❖ Nerve supply to extraocular muscles: (L6 SO4 All3)
✓ Oculomotor nerve (third cranial nerve) to superior rectus,
medial rectus, inferior rectus, and Inferior oblique.
✓ Trochlear nerve (fourth cranial nerve) to superior oblique.
✓ Abducens nerve (sixth cranial nerve) to lateral rectus.
❖ Actions of extraocular muscles:
✓ Medial rectus: adduction.
✓ Lateral rectus: abduction.
✓ Superior rectus and inferior oblique are elevators.
✓ Inferior rectus and superior oblique are depressors.
✓ Superior rectus is the only elevator in the abducted
position.
✓ Inferior oblique is the only elevator in the adducted
position.
✓ Inferior rectus is the only depressor in the abducted
position.
✓ Superior oblique is the only depressor in the adducted
position.

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 ❖ Binocular movements include:
✓ Versions (conjugate movements):
▪ These are binocular movements that occur simultaneously
in the same direction of gaze (dextroversion and
levoversion).
✓ Vergence (disconjugate movements):
▪ These are binocular movements in which both eyes move
in opposite directions (convergence inwards or divergence
outwards).
❖ Herring’s law of muscle innervation:
✓ It states that equal and simultaneous stimulatory
innervation is passed to yoke muscles (the muscles that
move the eye in the same direction of gaze e.g., medial
rectus of the right eye and lateral rectus of the left eye).

Binocular Single Vision:

• It is the state of having a single mental impression from two
original images displayed on the two retinae, attaining better
image sharpness, wider visual field, and stereopsis or depth
perception of images.
• It is a conditioned reflex that is not present at birth but is rather
acquired during the first 6-8 months of life and is completed
during the first 6-9 years of life. Once it is developed, it never
breaks. However, the age range of 6-8 months up to 6-9 years is
known as the critical period, where the reflex may be
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 compromised, and binocular single vision should be well
maintained to avoid image suppression (resulting in amblyopia).
• Requirements for the development of binocular single
vision:
❖ Binocular good sensory input from both eyes (with no
media opacities or refractive errors affecting the image
clarity).
❖ Binocular normal range of movement of extraocular
muscles.
❖ Normal higher control through normal cortical function.

Orthophoria/Orthotropia:
• It refers to the normal relation between both visual axes where
they are always parallel in any position of gaze.

Strabismus (Squint):
• It refers to any misalignment of the two visual axes in any
direction of gaze.
• Classification of strabismus:
1- Pseudo Squint or Apparent Squint:
❖ It is a state of orthotropia and orthophoria on examination,
but the eyes appear to have squint due to an abnormal
anatomical configuration.

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 ❖ Prominent epicanthic fold (epicanthus) is the major cause
of pseudo squint, which gives a false appearance of
esotropia.
❖ No complications can ensue from this condition, and it
requires no treatment.

2- Latent Squint (Heterophoria):

❖ It is a state or orthotropia under normal conditions with
a tendency for misalignment (deviation) of the eyes
under certain circumstances, mainly:
o Uncorrected errors of refraction, where the
condition is precipitated by excessive near work
with muscle fatigue.
o Loss of higher cortical control with illness or loss
of concentration.
❖ If heterophoria is neglected, it will lead to manifest
squint (heterotropia).
❖ Common types of heterophorias:
✓ Esophoria: tendency of the visual axis to deviate inwards,
which is common in uncorrected hypermetropia due to
excessive use of accommodation and hence excessive
use of accommodative convergence as a part of the
synkinesis.
✓ Exophoria: the tendency of the visual axis to deviate
outwards, which is common in unconnected myopia due to

175
 the disuse of accommodation and hence of
accommodative convergence.
❖ Clinical picture of heterophoria:
✓ It may be asymptomatic for a time interval.
✓ Periocular headache or eye strain may be the
presenting symptom.
✓ Intermittent diplopia is another encountered presenting
symptom, which usually presents after prolonged near
work resulting in muscle fatigue.
✓ Running letters in the text is another reported presenting
symptom.
✓ Hirschberg test (corneal light reflex) shows orthotropia.
✓ On performing the uncover test and alternate cover test,
heterophoria is reassured (by dissociating the higher
control through loss of the binocular vision which is the
major stimulus for image fusion).
✓ Treatment of heterophoria:
▪ Full correction of refractive errors is mandatory.
▪ No surgical treatment is indicated, and the condition
usually resolves with treatment of the cause, which is most
commonly an uncorrected error of refraction.

3- Non-paralytic (Concomitant) Squint:

• It is a state of deviation of the eyes, where the angle of
deviation remains the same in all positions of gaze and
the primary angle of deviation (when the patient fixes

176
 with the healthy eye) equals the secondary angle of
deviation (when the patient fixes with the squinted eye).
• It is mainly caused by uncorrected errors of refraction,
where the phoria changes into tropia if left untreated.
❖ Hypermetropia is the commonest refractive error to be
associated with strabismus, and it is associated with
convergent squint (esotropia), due to excessive
accommodation and hence excessive accommodative
convergence.
❖ Myopia is associated with divergent squint (exotropia),
due to lack of accommodation and hence lack of
accommodative convergence.
• In this type of concomitant squint, the deviation is
usually gradual, and diplopia is uncommonly
encountered (where it is only episodic in some
instances).
• Ocular movements are free with no limitation of ocular
motility (no muscle paralysis or restriction).
• Hirschberg test (corneal light reflex) shows the angle of
deviation.
• Cover test shows that the primary angle of deviation is
equal to the secondary angle of deviation.
• This strabismus usually resolves with correction of the
refractive error (cycloplegic refraction with
cyclopentolate 1% should be performed for full
correction of the refractive error).

177
• If there is a residual angle of squint after correction of
the refractive error, a surgical correction is performed for
the residual angle only.
❖ Recession surgery: to weaken the strong
muscle. The muscle is detached from its
normal site and re-attached posteriorly to
reduce its power.
❖ Resection: to strengthen the weak muscles.
The muscle is cut shorter and re-attached at
the same site, thus increasing its effective
power.

N.B. Any media opacities (such as central corneal

opacities or cataract) can result in unilateral strabismus
that occurs in the eye with the pathology and the angle of
squint does not alternate between both eyes.
N.B. You must exclude amblyopia with cases of unilateral
strabismus (in cases of unilateral media opacities or
asymmetrical refractive errors between both eyes).

• Amblyopia:
❖ It is a decrease in functional vision in one or both
eyes after treatment of any organic (anatomical)
or optical diseases of the visual pathway.

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 ❖ It could be due to ptosis, media opacities (corneal
or lenticular), or significantly asymmetrical errors
of refraction between both eyes (anisometropia).
❖ It can be alleviated by occlusion (patching) of the
healthy eye for variable time intervals along the
day, and by enhancing near vision activities.

4- Paralytic (Incomitant) Squint:

• It occurs due to lesions of the 3rd, 4th, or 6th cranial
nerves that supply the extraocular muscles.
❖ 3rd cranial nerve palsy: mostly due to diabetes
and hypertension, and results in exotropia,
hypotropia, and ptosis.
❖ 4th cranial nerve palsy: mostly due to head
trauma and results in hypertropia.
❖ 6th cranial nerve palsy: mostly due to
increased intracranial tension and results in
esotropia.
• This type of strabismus usually presents with
binocular diplopia that disappears by covering either
eye (due to stimulation of non-corresponding retinal
points). Diplopia is caused by its sudden onset, so it
is not compensated.
• There is a limitation of ocular motility in the direction
of gaze of the affected muscle.

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• Hirschberg test (corneal light reflex) shows the angle
of deviation.
• Cover test shows that the secondary angle of
deviation (when fixing with the squinted eye) is larger
than the primary angle of deviation (when fixing with
the healthy eye). This is attributed to Hering law of
equal and simultaneous innervation to yoke muscles,
so on trial of fixation by the squinted eye, the brain
sends extra impulses for it to fixate, and at the same
time sends extra impulses to its yoke muscle in the
other (healthy) eye. That is why the healthy eye
receives excessive impulses and the secondary
angle under the cover is larger than the initial
(primary) angle of deviation that was detected in the
squinted eye while fixing with the healthy eye.
• Neuroimaging as a CT scan or MRI is usually needed
to detect the possible intracranial pathologies.
• Treatment of incomitant (paralytic) strabismus
involves treatment of the underlying cause of cranial
nerve injury, and it usually resolves spontaneously
within a few months. Surgery is indicated only after
failure of recovery after 6 months of conservative
treatment.
❖ The type of surgery is muscle transposition and
not recession or resection, where the latter

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 surgeries give poor outcomes in paralytic
strabismus.

5- Restrictive Strabismus
• It is a type of strabismus that most commonly occurs
due to thyroid eye disease or trauma causing fractures
in the bony orbit. There is a restriction in the action of
one or more extraocular muscles.
• It resembles paralytic strabismus in its presentation,
except that the muscle is restricted (by fibrosis or
entrapment).
• Forced duction test is the clinical test to differentiate
between paralytic and restrictive strabismus, where the
test is positive (with restricted movement of the globe by
forceps) in cases of restrictive rather than paralytic
strabismus.
• Treatment is by transposition of the fibrosed muscles.

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 Ocular Trauma

Blunt Ocular Trauma

Open Globe Injuries
Intraocular Foreign Bodies
Sympathetic Ophthalmitis
Chemical Globe Injuries
Head Injuries and the Globe
Radiation Globe Injuries

Blunt Ocular Trauma

• Blunt ocular trauma can cause injury to various ocular structures,
including:
1- Eyelids:
❖ Hematoma: it usually resolves spontaneously, with
cold compresses for 24 hours followed by hot
fomentations till it resolves. Prophylactic systemic
antibiotics should be added to large hematomas to
guard against infections.
❖ Lacerations: vertical cut wounds of the eyelid have
a poorer prognosis than horizontal ones (as they are
perpendicular to the fibers of orbicularis oculi muscle,
so they heal by significant fibrosis and can cause
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 cicatricial ectropion. Hence, proper suturing of
vertical eyelid wounds is necessary, whereas
horizontal wounds may not be sutured, and plaster
tapes can be used for good wound coaptation).
❖ Ptosis: it may be mechanical (due to edema and
hematoma formation) or paralytic (due to nerve or
muscle injuries of eyelid muscles (levator or muller
muscle). Spontaneous resolution of traumatic ptosis
usually occurs within a few weeks to a few months.
2- Subconjunctival hemorrhage:
❖ It usually appears immediately after trauma.
❖ It is seen clinically as a bright red triangular area (with
its base towards the limbus).
❖ The posterior edge of a subconjunctival hemorrhage
can be localized.
❖ On the contrary, subconjunctival hemorrhage that
accompanies the fractured base of the skull has a
delayed onset, appears as a dark red triangular area
with its base towards the fornices, and you cannot
localize its posterior edge. This subconjunctival
hemorrhage is accompanied by panda eyes
appearance of dark periocular hematoma (panda
eyes or raccoon sign) and can be accompanied by
CSF rhinorrhea. MRI brain shows brain edema and
signs of cerebral affection by the head trauma.
3- Corneal affection:

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 ❖ Corneal abrasions and ulcers: topical antibiotics
should be prescribed with frequent lubricants and
eye patching (if no discharge).
❖ Ruptured globe: scleral rupture is more common
than corneal rupture following blunt ocular trauma. It
should be properly sutured after repositioning or
excision of any prolapsed iris (according to its
viability, where viable iris should be repositioned and
devitalized one should be excised) to guard against
endophthalmitis and sympathetic ophthalmitis.
4- Scleral affection:
❖ Ruptured globe: it is a term that refers to a wound
creation in the outer coat following blunt ocular
trauma. By the contre coup effect, the upper nasal
sclera is the commonest site for a ruptured globe
(where it is pushed against the trochlea at the upper
nasal orbit). Like its corneal counterpart, proper and
early suturing of the wound with repositioning or
excision of any prolapsed uveal tissue (ciliary body
or choroid) should be properly performed.
5- Hyphema:
❖ It is the presence of blood in the anterior chamber.
❖ The source of bleeding is usually the blood vessels
of the iris or ciliary body.

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❖ It is usually associated with secondary uveitis, with
inflammatory exudates arising from the inflamed iris
blood vessels.
❖ Complications:
✓ Staining of the corneal endothelium.
✓ Dispersion in the anterior chamber angle,
clogging the trabecular meshwork with
secondary open-angle glaucoma.
✓ Organization of blood in the angle of the
anterior chamber with peripheral anterior
synechiae and secondary angle closure
glaucoma.
❖ Treatment:
✓ Semi-sitting position (even during sleep) is
mandatory till resolution of hyphema. This is to
avoid corneal blood staining and dispersion of
blood in the anterior chamber and the angle
with secondary glaucoma.
✓ Follow up of the intraocular pressure with the
use of pressure-lowering agents if necessary
(but avoid miotics or prostaglandin analogues
as they induce uveitis and can aggravate the
co-existent inflammation with hyphema).
✓ Topical steroids are usually added to guard
against the organization of blood.

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 ✓ Aminocaproic acid (antifibrinolytic agent) is
used to guard against rebleeding in high-risk
patients (with bleeding tendencies,
hypertension, or sickle cell
hemoglobinopathies).
✓ Surgical evacuation is indicated if:
▪ Uncontrolled glaucoma by medical
treatment.
▪ Total hyphema (8-ball hyphema) due to
the high risk of complications (corneal
blood staining and recalcitrant
glaucoma).
6- Iridodialysis:
❖ It represents a disinsertion of the iris root
from its attachment to the ciliary body.
❖ The pupil is D-shaped (due to the
disinsertion of the base which disfigures
the pupil at this location).
❖ In such a condition, there is a double
pupil, with light reaching the eye through
two apertures. This causes uniocular
diplopia and requires surgical re-
suturing.
7- Lens affection:

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 ❖ Traumatic cataract (usually concussion cataract with
iris pigment imprint on the anterior capsule “Vossius
ring”).
❖ Ectopia lentis (subluxation, anterior or posterior
dislocation).
8- Choroidal rupture:
❖ This is seen as linear white lines that are concentric
with the optic disc (they represent areas where the
choroid ruptured with the appearance of the
underlying sclera). Visual acuity is affected only if the
fovea is affected.
9- Retinal affection:
❖ Commotio retinae: it represents swelling of the
retinal layers with blunt trauma. The retina appears
pale and edematous, and a cherry red spot
appearance (resembling that of central retinal artery
occlusion) can be seen. However, the condition has
a good visual prognosis and commonly resolves
spontaneously (with follow-up and avoidance of any
trauma till the retinal edema subsides).
❖ Retinal tears and retinal detachment: this can
occur with severe blunt traumas, and an immediate
surgical intervention should be performed, especially
if the macula is still attached.
10- Orbital affection:

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 ❖ Proptosis: due to retrobulbar collection of
hemorrhage and edema fluid.
❖ Enophthalmos: contrary to proptosis,
enophthalmos can occur due to retrobulbar fibrosis
following post-traumatic hemorrhage and
inflammation. Furthermore, an orbital floor fracture
can cause enophthalmos (and if the fracture is large
or the inferior rectus muscle is entrapped, surgical
intervention should be performed).

Open Globe Injuries

• It refers to injuries where the globe was liable to the ruptured
globe (in blunt trauma) or a lacerated wound (in traumas by sharp
instruments or gunshots).
• The lacerated wound includes either a penetrating globe injury
(with a site of entry detected) or a perforating injury (with both a
site of entry and exit detected).
• In open globe injuries, the presence of a retained intraocular
foreign body must be excluded.

• Clinical picture of open globe injuries:

❖ Sudden affection of vision (according to the site and extent
of lesions).

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 ❖ Shallow and irregular anterior chamber with associated
hypotony (highly suspicious of open globe injuries, either a
ruptured globe or lacerated wound).
❖ Associated secondary uveitis, uveal prolapse, and/or
vitreous prolapse may be present.
❖ Occult open globe injuries should be suspected in cases of
significant blunt trauma or sharp injuries where there is no
wound detected but there are signs of open globe injury
(mainly hypotony or shallow irregular anterior chamber).
The open wound is usually located underneath a
subconjunctival hemorrhage or chemotic conjunctiva.
Surgical exploration should be done in such conditions for
detecting the wound and proper repair.
• Management of open globe injuries:
❖ Immediate sterile patching of the eye should be performed
to reduce the incidence of infective endophthalmitis.
❖ Do not instill any topical eye drops with the existence of an
open globe injury to avoid the toxic effects of introducing
the drops intraocularly.
❖ Some studies recommend starting prophylactic systemic
antibiotics (especially if the injury was by a potentially
infected instrument). Yet their prophylactic effect has not
been proven.
❖ A CT scan on the orbit and globe should be performed to
detect the extent of damage (mainly posteriorly) and to
exclude the presence of intraocular foreign bodies.

189
 ❖ B-Scan ultrasound should be avoided, as the probe
compression on the globe can cause further damage.
❖ MRI is absolutely contraindicated if any metallic foreign
body is suspected, as this may lead to significant globe
damage.
❖ Surgical repair of the wound should be done as soon as
possible, with repositioning or excision of any prolapsed
uveal tissue, depending on its viability.
❖ Early enucleation (within the first two weeks of trauma) is
recommended for a severely damaged eye with no
salvageable vision. This choice is better than trials of repair
to reduce the incidence of sympathetic ophthalmitis.

• Clinical effects of open globe injuries:

❖ Mechanical damage (according to the severity of trauma).
❖ Introduction of infection (endophthalmitis or
panophthalmitis).
❖ Chemical effects of retained intraocular foreign bodies
(mainly siderosis with iron and chalcosis with copper).
❖ Sympathetic ophthalmitis.

Intraocular Foreign Bodies

1- Siderosis bulbi:
✓ If an iron foreign body is retained.
✓ It presents with:

190
 ▪ Hyperchromic heterochromia (iron and rust
deposition within the iris tissue).
▪ Secondary cataract.
▪ Secondary open-angle glaucoma (damage to the
trabecular meshwork by the deposited iron and its
rust).
▪ Pseudo retinitis pigmentosa (with iron deposition
in the retina leading to its toxic damage).
2- Chalcosis:
✓ If a copper foreign body is retained.
✓ It presents with:
▪ Kayser Fleisher ring (deposition of copper in the
Descemet’s membrane at the periphery of the
cornea near the limbus).
▪ Secondary cataract.

Sympathetic Ophthalmitis
• It is a bilateral granulomatous panuveitis that occurs after
variable periods of an open globe injury.
• The previously traumatized eye is known as the exciting eye and
the other healthy eye is known as the sympathizing eye.
• There is a higher incidence of its occurrence in severely
traumatized eyes with uveal prolapse that was left untreated for
some time. This is attributed to the fact that the melanin pigment
of the iris tissue is a sequestrated antigen that the immune
191
 system has not identified as a self-antigen. Hence, once the
trauma (especially with uveal prolapse) liberates the melanin
pigments from their capsules within the iris tissue, an immune
response starts against them. This immune response also
attacks the uveal tissue of the other (sympathizing) eye (reaching
it through the bloodstream), leading to bilateral granulomatous
panuveitis.
• Clinical picture:
❖ Evidence or history of trauma to the exciting eye (may be
many years following the trauma).
❖ One of the earliest signs in the sympathizing eye is reflex
lacrimation and photophobia (from the starting uveitis) with
the detection of aqueous flare and cells in the anterior
chamber on slit lamp examination.
❖ Mutton fat keratic precipitates on the corneal endothelium
(mainly macrophages of the granulomatous response).
❖ Dallen Fuchs nodules deposit in the choroid
(granulomatous reactions).
• Treatment:
❖ Prophylaxis against sympathetic ophthalmitis is mainly by
proper and prompt repair of any open globe injury, with
repositioning or excision of any uveal prolapse.
❖ Early enucleation of eyes with no salvageable vision.
❖ Warning signs against the start of sympathetic ophthalmitis
in the sympathizing eye should be explained to the patient
(mainly reflex lacrimation and photophobia).

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 ❖ If sympathetic ophthalmitis has already occurred, topical
and systemic steroids should be immediately initiated, with
immunosuppressives in resistant conditions.

Chemical Globe Injuries

• Alkali burns are more dangerous to the globe than
acid burns, as the former causes liquefactive
necrosis which allows further tissue penetration,
whereas the latter causes coagulative necrosis
which limits its tissue penetration.
• Presentation:
❖ Chemical injuries cause variable tissue
destruction (according to the type and amount
of chemicals that the eye was exposed to).
❖ Corneal lacerations and melting are very
common, together with soft tissue edema and
ciliary injection.
❖ One of the poor prognostic signs in chemical
injuries is the presence of patches of
conjunctival and episcleral ischemia (white
avascular patches, especially when these
patches approach the limbus).
❖ Chemical injuries can also be complicated by
cicatrization of the lid, conjunctiva, and cornea.

193
 • Management:
❖ Management of chemical injuries starts with
copious and thorough irrigation of the globe
with water or saline for 30 continuous minutes,
with lid eversion to remove any particulates
from underneath the lids.
❖ This is followed by topical antibiotics and
steroid eye drops.
❖ The use of a mydriatic/cycloplegic to eliminate
the associated uveitis and to guard against
synechiae formation is recommended.
❖ Topical ascorbate (vitamin C) is used to
promote collagen synthesis.
❖ Surgical removal of the already-formed
adhesions and debridement of any necrotic
tissue can be performed.
❖ Penetrating keratoplasty or the surgical
insertion of a keratoprosthesis is done for
severely traumatized corneas.

Head Injuries and the Globe

❖ Subconjunctival hemorrhage (base posteriorly) with
fracture base of the skull.
❖ Papilledema with increased intracranial tension.

194
 ❖ Visual field defects with lesions of the visual
pathway.
❖ Carotid-cavernous fistula.
❖ Paralytic squint (mainly trochlear nerve lesion with
head trauma and abducens nerve lesion with
increased intracranial tension).

Radiation Globe Injuries

❖ Infrared radiation (in glass blowers and people
working in furnaces) can cause true exfoliation of
the lens capsule and cataract formation.
❖ Ultraviolet radiation (skiing and metal welders) can
cause punctate epithelial erosions and corneal
ulcers.
❖ Solar radiation can cause “eclipse blindness” due to
foveal burning.
❖ Gamma radiation (for treating cancers) can cause
secondary cataract, retinopathies, and secondary
malignancies with retinoblastoma.

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 Ocular Tumors

Retinoblastoma
r of the Choroid

Retinoblastoma
• It is the most common primary malignant tumor in the first
three years of life.
• It arises from retinoblasts, which are persistent
embryological remnants of primitive photoreceptors, with a
co-existent loss of the tumor suppressor gene located at
chromosome 13.
• It usually arises in young children less than three years of
age, and it is bilateral in 20 % of cases.
• The tumor arises sporadically in most cases (94%), while
the remaining small percentage of cases have a positive
family history. A thorough fundus examination for the
siblings of any affected child till the age of three is therefore
mandatory to exclude possible inheritance.
• Clinical presentations:
❖ Leukocoria: this is the commonest presentation of
the tumor, which is noticed by the mother in cases of
a central tumor.

196
 ❖ Squint: it is the second most common presentation,
where it arises only when the macular area is
affected by the tumor.
❖ Masquerade syndrome: the tumor atypically
presents with uveitis.
❖ Secondary glaucoma (buphthalmos).
❖ Proptosis: when the tumor cells spread to the orbital
tissue.
❖ Metastasis: the tumor may spread from the orbit
along the optic nerve to the brain and may be lethal
in terminal cases in such a situation.
• Fundus picture:
❖ Thorough fundus examination for both eyes with full
pupillary dilatation and under general anesthesia is
mandatory (to reassure that all the tumor foci are
allocated).
❖ Endophytic lesion: the tumor grows inwards towards the
vitreous cavity and presents as a white elevated mass with
surface calcifications (cottage cheese appearance).
❖ Exophytic lesion: the tumor grows outwards towards the
choroid with possible exudative retinal detachment.
• Investigations:
❖ B-scan Ultrasound.
❖ MRI orbit and brain.
❖ CT Scan should be avoided as it may predispose the child
to secondary malignancies (mainly osteosarcoma of the

197
 surrounding bone and soft tissues). This is because such
children have defects in the tumor suppressor gene.
• Treatment:
❖ LASER or Cryotherapy: local therapy for single localized
and small tumors.
❖ Local Radiotherapy: in larger tumors where the LASER
or cryotherapy cannot eradicate the whole tumor.
❖ Chemotherapy: in bilateral or multifocal tumors.
❖ Enucleation: in blind eyes with no salvageable vision (to
avoid spread to the brain, a long optic nerve stump should
be removed and sent for histopathology to reassure the
absence of tumor cells dissemination). (Never perform
evisceration for tumors to avoid dissemination of
tumor cells).
❖ Exenteration: where the whole orbital tissue is removed
with the globe in cases of orbital spread of the tumor.

Malignant Melanoma of the Choroid

• It is the most common primary malignant tumor in adults.
• It arises from the uveal melanocytes in the choroid.
• It usually presents in old ages above 50 years and is usually
unilateral and unifocal.
• Clinical presentations:

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 ❖ Asymptomatic: if it does not involve the choroid in the
macular area, so it does not affect vision. It can be
accidentally discovered on routine fundus examination.
❖ Dropped vision: if it involves the choroid in the macular
area.
❖ Masquerade syndrome: presenting with uveitic attacks.
❖ Secondary glaucoma.
❖ Proptosis: if it spreads to the orbit.
❖ Metastasis: mainly to the liver, lungs, and bones.
• Fundus picture:
❖ The tumor usually presents as a pigmented, dome-shaped
mass (due to its subretinal location) with surface lipofuscin
pigment that gives its surface an orange color.
❖ When the tumor further grows, it can break through the
Bruch’s membrane of the choroid, where it now spreads
into the retina and towards the vitreous cavity giving a
characteristic collar stud or mushroom-shaped pattern.
• Investigations:
❖ B-Scan Ultrasound (the collar stud or mushroom pattern is
obvious if the Bruch’s membrane is ruptured).
❖ Investigate for possible metastasis to the liver (abdominal
CT and liver enzymes), lungs (CT chest), or bones (bone
scan).
• Differential diagnosis:

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 ❖ Choroidal nevus: it is the benign counterpart of malignant
melanoma that is usually smaller in size and stationary in
course. It requires no treatment.
❖ Metastatic choroidal lesions: the lesions are usually
bilateral and non-pigmented.
• Treatment:
❖ LASER or Cryotherapy: local therapy for localized and
small tumors.
❖ Local Radiotherapy: in larger tumors where the LASER
or cryotherapy cannot eradicate the whole tumor.
❖ Chemotherapy (Palliative treatment): in metastatic
tumors.
❖ Enucleation: in blind eyes with no salvageable vision
(Never perform evisceration for tumors to avoid
dissemination of tumor cells).
❖ Exenteration: where the whole orbital tissue is removed
with the globe in cases of orbital spread of the tumor.

N.B. How can intraocular tumors cause secondary glaucoma:

✓ Being a space-occupying lesion.

✓ Direct angle invasion by the tumor.
✓ Pushing of the iris-lens diaphragm anteriorly occluding the angle.
✓ Secondary uveitis blocking the trabecular meshwork.
✓ Seedling of tumor cells blocking the trabecular meshwork.
✓ Ischemia of the retinal tissue with neovessel formation
(neovascular glaucoma).

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 Optic Nerve

Anatomy of the Optic Nerve:

• The optic nerve represents the axons of the ganglion cells of the
retina, transmitting signals serving vision, color perception, and the
pupillary light reflex.

• It is surrounded by the 3 meninges (dura, arachnoid, and pia

mater) and CSF like the brain.

• It is also pierced by the central retinal artery and the central

retinal vein that runs within its substance. That is why compressive
optic nerve lesions result in vascular occlusions of these vessels (with
the vein preceding the artery due to its weaker tunic musculosa).

• Optic nerve functions can be tested by:

❖ Visual acuity.
❖ Color vision.
❖ Pupillary light reflex.
❖ Fundus examination for the optic disc.
❖ Visual field testing (perimetry).

Diseases of the Optic nerve

Optic Neuritis
Papilledema
Optic Atrophy
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 Optic Neuritis

• It is caused by inflammation of the axons of the optic nerve.

• Causes:

1- Infective Optic Neuritis:

❖ Viral: like measles, mumps, and influenza.

❖ Bacterial: extension from nearby sources (especially sinusitis).

2- Non-infective Optic Neuritis:

❖ Demyelination (Multiple Sclerosis): more common in young

females between 20 and 40 years of age.
❖ Toxic: mainly tobacco-induced, the effect of some drugs (such
as ethambutol antiepileptic), and methanol toxicity.
❖ Ischemic optic neuropathy: common with old age, and the risk
factors include giant cell arteritis, diabetes mellitus,
hypertension, and hyperlipidemia.

• Forms of Optic Neuritis:

❖ Papillitis:
✓ It refers to an inflammation of the optic disc head (optic papilla).
✓ It is more common in children with viral optic neuritis, which can
present bilaterally.
✓ It has a better visual prognosis than adult optic neuritis (with
proper control of viral infections).

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 ❖ Retrobulbar Neuritis:
✓ It refers to an inflammation of the part of the optic nerve behind
the eye.
✓ Fundus examination reveals normal optic disc in such conditions.
✓ It is common in demyelinating diseases (Multiple Sclerosis).

❖ Ischemic Neuritis:
✓ Common with old ages.
✓ The risk factors include giant cell arteritis, diabetes
mellitus, hypertension, and hyperlipidemia.

Clinical Picture and Investigations of Optic Neuritis:

❖ Visual acuity: drop of vision has a wide range from mild to

severe affection. In Multiple Sclerosis, it worsens then improves,
and can relapse.
❖ Color vision: washed-out colors, especially red, are common in
demyelinating diseases.
❖ Pupil: relative afferent papillary defect (RAPD) commonly
occurs.
❖ Fundus: changes in papillitis (where the optic disc is congested
with blurred margins), while it is normal in cases of retrobulbar
neuritis.
❖ Painful eye movement: in up and medial gazes, which is
manifest with retrobulbar neuritis (mainly due to Myelinating

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 Sclerosis). This is because the optic nerve sheath gives a partial
origin to both the superior and medial recti.
❖ Visual field: Central or Centrocecal scotomas with optic neuritis
are common, whereas altitudinal field defects occur in cases with
ischemic optic neuropathy.
❖ Visual Evoked Potential (VEP): shows delayed latency and
reduced amplitude of P100 wave.
❖ Investigations for the cause: mainly MRI brain for Multiple
Sclerosis.

Differential Diagnosis of Disc Edema:

1- Pseudo-papilledema: must be excluded, which occurs in high

axial hyperopes (crowded disc with obliterated cup).

2- General (bilateral):

❖ Papilledema (disc edema due to increased intracranial tension).

❖ Malignant hypertension.

3- Local (unilateral):

❖ Papillitis.
❖ Orbital lesions compressing the optic nerve and the central
retinal vein running through its substance (mainly thyroid
ophthalmopathy, optic nerve tumors, trauma, vascular and
inflammatory causes).

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Treatment of Optic Neuropathy:

❖ Pulsed steroids therapy:

✓ Intravenous one gram (1000 mg) of methylprednisolone is
injected intravenously.
✓ It must only be given in the cardiac care unit (with good
monitoring of the cardiac condition for ventricular tachycardia,
blood pressure, and blood sugar level).
✓ Pulsed steroids are injected for 3 successive days, followed by
oral steroids for 7-10 days then gradual tapering is performed.
✓ If demyelination is proven and in relapsing cases, disease-
modifying agents, given by neurologists, can prevent the
recurrence of attacks.

Papilledema

• Bilateral swelling of the optic disc head due to increased

intracranial tension.

• Causes:

❖ Space-occupying lesions such as brain tumors, abscesses, and

subarachnoid hemorrhage.
❖ Cerebral venous sinus thrombosis.
❖ Flow obstruction like congenital aqueduct stenosis.
❖ Idiopathic intracranial hypertension: common in obese young
females, especially those who take oral contraceptive pills.

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• Clinical picture:

❖ General symptoms: headache mainly on awakening, projectile

vomiting, and maybe drowsiness in some cases.
❖ Vision: normal in the early stages, but the patient can
experience transient visual loss in early cases with the
transudation of fluids from the compressed veins at the optic
disc. Vision can deteriorate in neglected cases with optic atrophy
development. However, color washout can be an early symptom.
❖ Fundus examination:
✓ Early Papilledema: nasal blurring of the disc margins.
✓ Established papilledema: blurring extends all around the optic
discs, with raised edges, venous engorgement, hemorrhages,
and sometimes cotton wool spots with ischemic peripapillary
retinal areas.
✓ Chronic/old papilledema: disc elevation remains but cotton
wool spots and hemorrhages subside.
✓ Post-papilledema optic atrophy: if disc edema is neglected,
death of axons occurs, and the disc looks pale with irregular
margins and greyish-white discoloration (due to gliosis).
N.B. The blurring of the optic disc margins in early and established
papilledema is mainly caused by the transudation of fluids and
blood from the congested peripapillary veins with optic nerve
compression, as the central retinal vein runs within the substance
of the optic nerve and once it is compressed, it affects the venous
drainage of the whole retinal veins.

• Investigations:
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 ❖ Brain MRI (or CT) is important to detect the intracranial cause.
❖ Visual field shows an enlargement of the blind spot.
❖ Lumbar puncture to measure the CSF pressure.

• Treatment:

❖ Of the cause by referring to neurosurgery.

❖ In cases with idiopathic intracranial hypertension, stopping the
use of oral contraceptive pills and using oral acetazolamide
(which decreases the production of CSF) are the main lines of
treatment. Furthermore, weight loss is highly encouraged.
❖ Ventriculoperitoneal shunts if needed.

Optic Atrophy

• It refers to the pallor of the optic disc due to the death of the
ganglion cells.

• Types:

❖ Primary optic atrophy: it occurs with no previous optic nerve

pathologies or edema preceding the condition, and it may be
congenital or may be caused by compressive lesions of the
visual pathway (retrobulbar pathologies). The disc is pale and
white, but the margins are well-defined.
❖ Secondary optic atrophy: it occurs after optic disc edema
(post-papilledema), papillitis (post-papillitis), or ischemic optic
neuropathy. The disc is greyish-white with blurred margins.

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 ❖ Consecutive optic atrophy: it occurs following retinal diseases
(commonly with retinitis pigmentosa or central retinal artery
occlusion). The disc is waxy and pale with well-defined margins.
❖ Post glaucomatous optic atrophy: it occurs with the end
stages of glaucoma. The disc is cupped with well-defined
margins.

Neuro-Ophthalmology

• Six out of the twelve cranial nerves serve the eye, namely:

❖ 2nd: Optic nerve: responsible for vision.

❖ 3rd: Oculomotor: responsible for motility of levator muscle and
many extraocular muscles.
❖ 4th: Trochlear: responsible for superior oblique motility.
❖ 5th: Trigeminal: responsible for ocular sensation.
❖ 6th: Abducens: responsible for lateral rectus motility.
❖ 7th: facial: responsible for orbicularis oculi function of lid closure
and also plays a role in lacrimal pump function.

• Optic Nerve:

❖ Functions of the optic nerve can be assessed by:

1- Visual acuity testing.

2- Color vision testing.

3- Pupil examination.

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4- Fundus examination to visualize the optic disc.

5- Visual field testing (perimetry).

• The optic nerve is the only nerve in the body that can be seen
through fundus examination.

• It is important to comment on the optic disc regarding color (pallor

or congestion), disc margins, cup-to-disc ratio (normally less than 0.4),
and surrounding vessels.

• Pupillary Light Reflex:

❖ When light falls on the eye, it causes stimulation of the optic

nerve.
❖ Eighty percent of the optic nerve fibers are responsible for
transmitting visual sensation, while 20% carry pupillary fibers
that are responsible for the afferent of the pupillary light reflex.
❖ Those fibers of the pupillary light reflex within the optic nerve
have a superficial location than the deeper visual fibers. That is
why they are affected earlier than the visual fibers by optic nerve
compression.
❖ Visual fibers running within the optic nerve reach to the optic
chiasm, optic tract, and lateral geniculate body, then reach the
occipital lobe of the brain through optic radiation.
❖ On the other hand, the pupillary fibers do not follow the same
course as the visual fibers. As they reach the anterior two-thirds
of the optic tract, they leave the pathway of the visual fibers and
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 pass to the pretectal nucleus of the midbrain. From there, fibers
to bilateral Edinger Westphal nuclei of the midbrain emerge.
Thus, stimulation of one side of the optic nerve (one pretectal
nucleus) causes bilateral stimulation of both Edinger Westphal
nuclei, which are the center of the pupillary light reflex from
where efferent fibers pass through the oculomotor nerve to reach
the ciliary ganglion where they relay then travel through the short
ciliary nerves to the constrictor pupillae muscle to cause pupillary
constriction.
❖ Such fibers that pass from one pretectal nucleus to both Edinger
Westphal nuclei are responsible for the indirect (consensual)
pupillary constriction that occurs when light falls on one eye.
Hence, when a torch light shines on one pupil, a direct light reflex
(pupillary constriction) happens in this eye, and an indirect
(consensual) light reflex occurs in the other eye simultaneously.
These two reflexes are connected and affected by each other, so
the loss of one of them results in the loss of the other.

• Relative Afferent Pupillary Defect (RAPD):

❖ It occurs in optic nerve lesions or extensive retinal lesions which

cause failure of the optic nerve to inform the pretectal nucleus
about the presence of light on the pupil. It has variable degrees
depending on the degree of optic nerve or retinal damage.
❖ In mild forms of RAPD, when swinging the light from the normal
to the diseased eye, it constricts to a weaker degree compared

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 to the other (healthy) eye. In more severe forms of RAPD, the
diseased eye fails to constrict from the very beginning, and it
dilates when light shines on it due to a lack of perception of light
falling on the diseased pupil.

• Autonomic Supply of the Eye and Disorders of the

Pupil
❖ Horner’s Syndrome
✓ It is caused by interruption of the sympathetic supply of the eye
due to any lesion along the sympathetic pathway, mainly
Pancoast tumor of the lung and carotid artery dissection or
aneurysm.
✓ It mainly manifests by:
o Mild ptosis (due to interruption of the sympathetic supply to the
muller muscle).
o Miosis (due to interruption of the sympathetic supply to dilator
pupillae muscle). This causes anisocoria (unequal pupil sizes).
o Hemifacial anhidrosis (due to the affection of sympathetic fibers
to the sweat glands of the corresponding half of the face).
o Flushing (due to interruption of the sympathetic supply to the
corresponding blood vessels of the face).

• Visual Pathway and its Lesions (80% of optic nerve

fibers travel along this course):

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❖ Both optic nerves travel to the cranial cavity where they unite at
the optic chiasma. This is where the nasal fibers from both eyes
decussate and temporal fibers pass uncrossed to form the optic
tract.
❖ The optic tract reaches the lateral geniculate body, from there
the optic radiation arises passing through both the temporal and
the parietal lobes of the brain.
❖ The final station is the primary visual cortex in the medial wall of
the occipital lobe.
❖ According to the site of the lesion along the visual pathway,
visual field defects occur as follows:
✓ Lesion at the optic nerve: total field loss.
✓ Lesion at the center of the optic chiasma: bitemporal
hemianopia (mainly pituitary gland tumors). This is a
heteronomous hemianopia (at two halves of the visual field
that correspond to opposite directions of gaze).
✓ Lesion at the optic tract: homonymous hemianopia (at
the corresponding visual fields in both eyes that look in the
same direction of gaze).
✓ Lesion at the occipital lobe: homonymous hemianopia
with macular sparing (as the macula has a collateral
vascular supply and also due to the very large macular
representation in the occipital cortex).

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• Sensory Supply of the Eye:

❖ The ophthalmic nerve is the first branch of the trigeminal nerve,

and it supplies sensation to the eye (mainly through branches of
the nasociliary nerve).
❖ Corneal sensation is the most important sensory supply to the
globe, as corneal sensation has a protective function. It can be
tested by a cotton tip that is approached to the globe gently while
the patient is looking straight ahead. Affection of corneal
sensation can lead to neurotrophic ulcers, and it is mainly caused
by:
✓ Recurrent trigeminal neuralgia.
✓ Recurrent herpetic viral keratitis.
✓ Iatrogenic corneal hypoesthesia by the abuse of topical
anesthetics.

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