EYELID

Chalazion obstruction of the orifice of the mebomian gland leading to lipogranulatomous inflammation of the
gland. (painless swelling)
Hordeolum ext./stye acute infection of the zeis and moll. (painful)
Hordeolum internum acute infection of the mebomian gland. (painful)
Ulcerative/infectious chronic infection of gland of zeis and moll. (gluing+ crusts)
blepharitis
Trichiasis misdirection of eye lashes towards globe
Distichiasis Extra row of eyelashes
Madarosis loss of eyelashes
Poliosis patch of white hair in eye lashes
-Tylosis hypertrophy & thickening of eyelid margin
Ankyloblepharon adhesion of lid margins
Seborrheic/squamous disorder of gland of zeis and moll. (dandruff like deposition)
blepharitis
Meibomianitis/posterior inflammation of meibomian glands (excessive fatty acid secretion) (burning sensation)
blepharitis
Phthiriasis palpebrarum lice infestation by phthirus pubis/ crab lice
Congenital Entropion eyelid margin turned inwards towards globe caused by congenital deformity of the tarsal plate
Congenital ectropion eye margin everted away from eyeball due to developmental deformity of eyelid
Senile entropion eyelid margin turned inwards towards globe due to old age (most common, usually lower eyelid)
Senile ectropion due to senile laxity of the tissues of the eyelid (most common)
Cicatricial entropion scarring of palpebral conjunctiva (usually upper eyelid)
Cicatricial ectropion scarring of contracture of skin and underlying tissues which pull eyelid away from the globe
Spastic entropion excessive contraction of orbicularis muscles, atrophy of lower eyelid retractor (usually after ocular
surgery)
Paralytic ectropion due to facial nerve paralysis which leads to atony of orbicularis muscle
Simple congenital ptosis reduced levator function
Synkinetic congenital due to misdirected cross innervation b/w oculomotor and mandibular branch of trigeminal nerve
ptosis supplying muscles of mastication (jaw closed, ptosis happen)
Blepharophimosis Party Bitches Escaped Thriftstore. Ptosis, Blepharophimosis, telecanthus, epicanthus inversus.
syndrome (congenital
ptosis)
Neurogenic ptosis CNIII lesion, horner’s syndrome (partial ptosis)
Myogenic ptosis due to myasthenia gravis (worse in evening)
Aponeurotic ptosis due to dehiscence, stretching or disinsertion of levator aponeurosis
Squamous cell most common benign epithelia tumor. HPV
papilloma
Capillary hemangioma common in children, benign pinkish red lesion
Xanthelasma common in middle aged women, benign, lipid deposits in histiocytes of eyelid skin, creamy yellow
lesions, hyperlipidemia
Neurofibroma found in ppl with neurofibromatosis type 1, benign tumor of nerve sheath, S shaped ptosis
Basal cell carcinoma most common malignancy of eyelid, usually lower eyelid, fair skinned people exposed to sun
Squamous cell 2nd most common malignancy. Bowen disease (type of SCCA), scaly hyper keratotic patch
carcinoma
Sebaceous gland malignant tumor arising from meibomian or zeis glands, upper eyelid
carcinoma

LACRIMAL
Congenital nasolacrimal Non canalization of lacrimal duct at of the membrane of nasolacrimal duct or maldevelopment of
duct obstruction punctum and canaliculi. Common in babies
Aquired nasolacrimal Common in adults. Trauma, sarcoidosis, tumors
duct obstruction
DCR Passage is created between the lacrimal sac and the nasal cavity through bony ostium
Dacryocystitis (medial) Inflammation of the lacrimal sac (excretory system). Acute- painful, lots of swelling at medial canthus,
inflammation/infection, epiphora. Chronic- painless, swelling Is mid.
Dacryoadenitis Inflammation of lacrimal gland (secretory system), S-shaped lid. Acute- Epstein bar virus, painful
(superolateral) proptosis. Chronic- painless, always secondary; sjogren’s syndrome
Keratoconjunctivitis Aqueous tear deficiency- Sjogren synd, rheumatoid arthritis, sys lupus synd, Steven Johnson’s synd.
sicca/ DES dry eyes Evaporative tear dysfunction- meibomian gland dysfunction
syndrome
Lacrimation Increased tear production by irritation
Epiphora Decreased drainage by lacrimal pump failure or obstruction causing excessive watering

CONJUNCTIVA
Bacterial: Mucopurulent Acute, Pink eye, mucopurulent discharge
conjunctivitis
Bacterial: Purulent conj Hyperacute, purulent discharge, corneal ulceration, N.Gonorrhea, infants from birth canal,
hospitalization
VIRAL COJUNCTIVITIS
Name Cause Symptoms Signs Diagnosis Treatment
Epidemic -Adenovirus 8, -Watery -Edema -PCR -Spontaneous/self-
keratoconjunctivitis 19, 37 discharge -Chemosis -Giemsa stain resolving
-Highly infectious -Redness -sub conjunctival -Immuno- -Antiviral
-Discomfort hemorrhage fluorescence -Antibiotic
-Follicles Pseudomembrane test -Steroids
formation
Pharyngoconjunctival -Adenovirus 3, 4, -Pharyngitis, Same symptoms Same Same
fever 7 headache, fever but less severe
Picornavirus -Enterovirus 70 -Bilateral redness -Punctate keratitis ↑IgG Steroid, topical
-Highly -Watery -Edema
contagious discharge -Chemosis
-Follicles -Conj. hemorrhage
Herpes simplex -HSV -Vesicles -Follicles -↓corneal Supportive
-Watery -Hyperemia sensitivity
Discharge -Chemosis -↑Ig
-Follicles -Serous disch -Fluorescein
-Dendrites antibody test
Molluscum -Pox virus -Mucoid -Warg nodule on - -Spontaneous
discharge lid resolution
-Follicles -Bulbar nodule on -Cryotherapy
lid -Cauterization
-no chemosis -Shave excision
-Punctate keratitis

Trachoma Cicatrial keratoconjunctivitis, chlamydia type A.B,Ba,C, enlarged preauricular lymphnodes, leading
cause of preventable blindness, herberts pits, scar
Neonatal conjunctivitis Chlamidyal type D-K (mucopurulent), HSV II (blepharoconjunctivitis), N.gonorrhea (purulent
discharge), chemical (prophylactic silver nitrate/antibiotics), swollen lids
Vernal conjunctivitis/ Type I & IV hypersensitivity, common in spring, palpebral (ropy secretion, cobble stone, ptosis), limbal
spring catarrh (allergic) (trantus dots), mixed (keratoconus, plaque and shield ulcer)
Steven johnson Acute vesiculobullous reaction to a medication of infection. Sulfonamides, HSV, symptoms > Rats Get
syndrome Pissed With Controlling Mouse Killing List (see pg 73), lip crusting, target lesions on skin
Pterygium Degenerative conjunctiva where there is triangular fibrovascular connective tissue, stocker line, iron
deposition
Pseudo pterygium Fold of bulbar conjunctiva, inflammatory, probe can be passed under the neck
Pinguecula Yellowish white mass on bulbar conjunctiva, degenerative, precursor of pterygium
Xerophthalmia ↓vitA due to chronic alchoholism, leading cause of childhood blinding, xerosis, bitot spots
Subconjunctival hemrg Whooping cough, blood thinner, severe HTN, trauma, ↑strain, ↓vitK
 CORNEA
Bacterial corneal ulcer Commonly staph, strep, hypopyon, halos, hazy cornea, corneal stain positive, IOP↑, treatment for
descemetocele is pressure bandage, conjunctival flap, amniotic membrane transplant, grafting &
cyanoacrylate glue
Fungal keratitis Filamentous (aspergillus, tropical, greyish white infiltrations, satellite lesions) yeasts (candida,
temperate, yellow white infiltration)
Acanthamoeba keratitis Amoeba in water & soil, contact lens wearer, limbitis, ring abscess
Herpes simlpex keratitis By HSV (type 1 above the waist, type 2 below) lodging in the trigeminal ganglion reactivated travels
along sens axons to cornea, dendritic ulcer, corneal sensitivity↓, acylclovir
Herpes Zoster HHV-3, skin and ocular lesions, hutchison’s sign, epithelial keratitis & microdendritic ulcers
ophthalmicus
Keratopathy Disturbance is the metabolic activity of corneal epithelium
Neurotropic Degenerative, Damage to CN5 (trigeminal) due to trauma, lasik, tumor, diabetes, painless red eye w/
keratopathy visual acuity↓
Exposure keratopathy Incomplete closure of eye lid due to bells palsy, ectropion, thyroid-proptosis
Keratoconus Central stromal thinning leading to bulging of central cornea, painless progressive visual acuity↓,
distant direct opthalmosopy- oil droplet, retinoscopy- scissor reflex. Munson’s sign. Associated with
vernal kerato conjunctivitis
Keratoplasty Procedure of diseased cornea replacement by doners cornea
Penetrating Complete thickness graft
keratoplasty
Superficial keratoplasty Partial thickness graft, anterior 1/3rd of cornea
Deep ant. keratoplasty Anterior 90% (still partial)
Limbal stem cell Indicated in steven Johnson’s syndrome
grafting

Lens and Cataract

Leukoria White reflex in pupillary area due to congenital cataract (m/c), retinoblastoma, endophthalmitis
Rossete cataract Traumatic concussion
Glass blowers cataract Infrared radiation/ heat
Snowstorm cataract Diabetes
Oil drop cataract Galactsemia
Sunflower cataract Wilson disease, copper poisoning
Syndermatotic cataract Atopic dermatitis
Posterior subcapsular A central cat, saucer shape opacities, due to steroid use, inline of visual axis causing loss of vision
cataract
Cortical cuniform Cause of hydration of lens due to changes in permeability. Incipent, immature, intumescent, and
cataract mature cataract
Incipent cat Constantly changing refractive error seen
Immature cat Refractive index of cortex increases causing ↓refractive power and hypermetropia, +iris shadow test
Intumescent cat Attack of angle closure glaucoma
Mature cat Fully opaque, entire lens white, -iris shadow test
Nuclear cataract Dehydration and sclerosis, inelastic and hard, ↑refractive power, myopia
Hypermature cataract Denatured protein leaks producing phacolytic glaucoma
Congenital cataract Remove asap or will develop amblyopia, Rubella (most common), radiation xray, corticosteroids,
diabetes, forceps delivery
Subluxation/luxation Collagenous ligament degenerate causing dislocation of lens. Sublux-partial, lux-fully
Central cataract Includes Post. subcapsular & nuclear cataract, has daytime cataract worsening, improves with dark
glasses cause of pupillary dilation in daytime
Phacomorphic glaucom Swollen lens pushing against iris causing pupillary block
Phacolytic glaucoma Protein leak, macrophages phagocytose proteins blocking trabecular meshwork
Biometry Calculation of lens power done by keratometry (curvature of ant conreal surface K) and by A-scan-
axial length L (ant post length). SRK formula: 𝑷𝑷 = 𝑨𝑨 − 𝟐𝟐. 𝟓𝟓𝟓𝟓 − 𝟎𝟎. 𝟗𝟗𝟗𝟗
Extra capsular cataract Leaving posterior capsule intact (phacoemulsification, Femtosecond laser cataract extraction, manual
extraction (ECCE) small extraction surgery-tunnel incision, conventional)
Phacoemulsification Preferred cause its astigmatism free, suture less, precise. Pad bandage needed, safe anesthesia is
peribulbar
Intracapsular cataract Removal of cataract along with its capsule, indicated in subluxated lens, common complication is
extraction (ICCE) vitreous collapse
After cataract Cataract after surgery, removed with YAG laser
Pars plana Lensectomy Removed through pars plana, indicated in congenital cataract, lens and ant vitreous are removed
Anterior chamber lens Indicated in ICCE or rupture of posterior capsule, complications are glaucoma, uveitis
Ectopia lentis Displacement of lens from its normal position, trauma, hypermature cataract, Marfan’s syndrome.
Iridodonesis (tremulation of iris) demonstrated in children

GLAUCOMA
Glaucoma Progressive optic neuropathy with visual field defects. Cupping- cup disc ratio > 0.7/ difference of 0.2
between eyes, neuroretinal rim turns pale, nasalization of optic disc blood vessels, splinter hemorhage
Normo tensive Normal IOP (10-21mmhg) with damage to the optic nerve (cupping) and visual field defects
glaucoma
Ocular HTN (glaucoma ↑IOP without cupping visual field defects
suspect)
Primary open angle Bilateral optic neuropathy, increased resistance in trabecular meshwork due to loss of trabeculocytes,
glaucoma open angle, no secondary cause, IOP>21, most common type, more common in black, myopes, steroid
users and diabetes
Primary closed angle Bilateral, raised IOP due to closed angle, more common in females, hyperopes, small eye having
glaucoma (PACG) people
Acute PACG Due to sudden closure of angle of ant chamber by iris, pain, ↑pressure-ischemia of iris-↑PG’s-
inflammation, emergency
Chronic PACG Anterior synechia formation, mainly surgical
Absolute glaucoma End stage of closed angle glaucoma, dilated & non reactive pupil, optic atrophy (full cupping), stony
(PACG) hard eye
Secondary glaucomas
Corneal ulcer Causes glaucoma, nonperforated ulcer-trabecular obstruction caused by exudate, perforated ulcer-
collapse of anterior chamber resulting in ant. Synechiae formation, descement membrane involved
Inflammatory glaucoma Iridocyclitis causing glaucoma in many ways
Pigmentary glaucoma Open angle, deposition of pigments in trabecular meshwork by iris epithelium
Neovascular glaucoma Aka rubeotic glaucoma, ischemic central retinal vein occlusion or diabetic retinopathy causing release
of VEGF inducing neovascularization which causes angle block by neovascular tissue, protein leakage
Phacomorphic Closure angle, swollen cataract lens causing pupillary block
glaucoma
Phacolytic glaucoma Open angle, hypermature cataract protein leakage blocking trabecular meshwork
Phacotoxic glaucoma Open angle, lens capsule rupture causing uveal tissue inflammation and protein leakage, trabecular
obstruction by proteins and inflammatory cells
Pupillary block glauc Close angle, dislocated lens
Pseudoexfoliative glc Open angle, exfoliated material deposition in trabecular
Haematogenic Intraocular hemorhage, red cell glaucoma- obstruction by RBC’s, hemolytic glaucoma- macrophages
glaucoma phagocytosing RBC’s, ghost cell glaucoma- occurs in vitreous hemorrhage having degenerated RBC’s
Aphakic glaucoma Caused by cataract extraction, more common in ICCE
Malignant glaucoma Aka ciliary block glaucoma, after glaucoma/cataract surgery, treatment is viterous aspiration
Cancer causing glaucs Retinoblastoma & malignant melanoma (inflam. cells, neovascularization of angle, mechanical)
Angle recession glauc Blunt trauma, damage to ciliary body and meshwork causing fibrosis causing angle block
Congenital glaucoma True congenital-↑IOP at birth, primary infantile- <3 yrs- juvenile glaucoma 3-16yrs
Primary infantile Impaired aqueous flow due to maldevelopment of ant chamber angle, haab’s striae, corneal haze &
glaucoma edema, buphthalmos (big eye balls with blue sclera), always surgical-goniotomy preferred if cornea
clear
Iridectomy Hole in periphery or iris for drainage of aqueous, indicated in prophylaxis of primary angle closure glc
Goniotomy Incision made in the angle to establish communication between anterior angle and canal of schlemm,
indicated in congenital glaucoma with clear cornea
Trabeculectomy Creating a fistula covered by a superficial scleral flap to allow aqueous outflow from the anterior
chamber through a surgical corneoscleral opening into the subconjunctival and subtenon space, done
with anti-scarring mitomycin C/ 5 fluorouracil, preferred in open angle and others too
Trabeculotomy Trabecular meshwork is broken up by passing a trabeculotome into schlemm canal and rotating it into
anterior chamber thus establishing a communication between aqueous humor and shclemm canal,
indicated in congenital glaucoma with hazy cornea

UVEAL TRACT & VITEROUS

Uveal tract Made of choroid, ciliary body and iris
Acute iridocyclitis Most common form of uveitis, ciliary body and iris, idiopathic, associated with ankylosing spondylitis
(acute anterior uveitis) in young, pupil constricted sluggish, KPs in cornea, mydriatic cycloplegic an steoirds, cells in ant chamb
Chronic iridocyclitis Persistent but less than 3 months, KPs large greasy mutton fat, koeppe & busacca nodules
(chronic ant. uveitis) (granulomas), complications- complicated cataract, cyclitic membrane, band keratopathy
Intermediate uveitis Pars plana, post ciliary body, vitreous base. Pars planitis-snowballs & snowbanking in vitreous, floaters
Choroiditis (Posterior Chorioretinitis, metamorphosia- distorted objects, micropsia, macropsia, photopsia-flashes of light,
uveitis) floaters, scotoma, complication- exudative retinal detachment
Toxoplasmosis Toxoplasma gondii, obligate intracellular protozoan parasite, from cats, retinochoroiditis, convulsions
TB Ant uveitis-Fibrinous exudate, disseminated choroiditis-yellowish lesions called tubercles, retinal
detachment and macular star
Endophthalmitis Inflammation of intraocular structures are normal, cause- trauma surgery perforation, hazy cornea,
loss of red reflex, parsplana vitrectomy when no response to medical treatment
Panophthalmitis Inflammation of eyeball including orbital structures, extraocular movements restricted & painful
Sympathetic Bilateral granulomatous panuveitis after penetrating ocular injury, sympathizing eye is non injured
opthalmitis fellow eye developing uveitis, dalen fuhcs nodules
Viteorus liquefaction Most common degenerative disorder of vitreous, trauma, inflammation, photocoagulation
Post vitreous Common in above 60 years, synchitic fluid collects behind vitreous, flashes of light and floaters
detachment
Vitreous hemorrhage Accumulation of blood in the vitreous cavity, due to angiopathies, sudden onset of floaters and
sudden painless vision loss, no fundal glow, ↓visual acuity, slit lamp examination, ghost cell glaucoma
Vitrectomy Surgical removal of vitreous, indications of pars plana vitrectomy- endophthalmitis, vitreous
hemorrhage

RETINA
Diabetic Non inflammatory, progressive dysfunction of retinal vasculature secondary to hyperglycemia.
retinopathy/DR Treatment- anti VEGF, burn hypoxic retina, destroy leakage areas, vitrectomy for vit hem.
Background DR Microaneurysms, retinal edema, hard exudates, dot & dark hemorrhages
Pre-proliferative stage Venous dilation & sausage segmentation, cotton wool spots, IRMA
Proliferative stage Neovascularization of retina/iris, vitreous hemorrhage, pre-retinal boatshaped hemorrhage in
retrohyaloid space
Diabetic maculopathy m/c cause of diabetic visual loss and blindness- macular edema
HTN retinopathy Sudden painless bilateral visual loss, splinter flame shaped hemorrhages, salus sign, silver wire
appearance of arterioles, cotton wool spots
Ischemic Central retinal Sudden & severe unilateral visual loss, v/a is counting fingers, deep blot & flame shaped hemorrhages,
vein occlusion cotton wool spots, disc edema, tomato splash appearance. Complication- rubiosis iridis
Central retinal artery m/c cause thrombosis, amaurosis fugax- sudden, painless, unilateral loss of vision. Fundus exam-
occlusion cherry red spot, pale retina, cattle tracking, arterial narrowing
Branch retinal artery m/c cause embolism, altitudinal & sectional visual field loss
occlusion
Age related macular Degeneration of macula causing irreversible vision loss. Risk- drusen formation at post pole, smoking,
degeneration (ARMD) aspirin, ↑cholesterol, obesity. Dry ARMD- m/c form, drusen, gradual ↓vision. Wet ARMD- choroidal
neovascularization leaking serous exudate, sudden, metamorphopsia
Retinal detachment Separation of sensory retina from retinal pigment epithelium by sub retinal fluid
Rhegmatogenous RD Break in the sensory retina, high myopic ppl, flashing lights & floaters, tobacco dust/ shaffer’s sign.
Goldmann 3 mirror for diagnosis.
Tractional RD Contraction of vitreous retinal membrane, diabetes, retinopathy of prematurity, eales disease
Serous/exudative RD Accumulation of exudative fluid in sub retinal space, related to vascular patho, retino blastoma & syst
HTN
Retinitis pigmentosa Group of hereditary disorders resulting in pigmentary retinal dystrophy predominantly affecting rods
and cones, pigmentary bone corpuscles/ bone spicules, night blindness ↑dark adaption time
Retino blastoma Congenital malignant tumor arising from retinoblasts, < 3 years, chromosome 13q 14, m/c leukocoria,
convergent squint, calcium deposition, proptosis

Optic nerve
Optic neuritis Inflammation of optic nerve anywhere along the route, m/c cause multiple sclerosis, syphilis, varicella
zoster virus, RAPD-negative swinging light test, papillitis, neuroretinitis, retrobulbar optic neuritis
Neuroretinitis (ON) Retinal involvement & macular star, RAPD
Papillitis (ON) Inflammation of optic nerve head, m/c type, RAPD present, cells in posterior vitreous,
Retrobulbar optic Inflammation of orbital part of optic n, normal fundus appearance with RAPD, pain with eye movt,
neuritis (ON) acute ↓vision, associated with multiple sclerosis, defective color vision
Papilloedema Passive edema of optic nerve head secondary to raised intracranial pressure, V/A normal but attacks
of blurred vision, macular star incomplete, paton’s lines, champagne cork appearance of optic disc
Arteritic Anterior Caused by giant cell arteritis, jaw claudication, headache, CRP in blood
ischemic optic
neuropathy (AION)
Anteroir ischemic optic HTN, DM, hyperlipidemia, lipid profile test↑, altitudinal visual field defects
neuropathy
Compressive ON Pituitary tumor, visual loss painless and gradual
Infiltrative ON Inflammation, infections, visual loss painless gradual
Nutritional and toxic ON Tobacco-alchohol amblyopia, ↓B12 due to alcohol excess
Toxic optic neuropathy Methanol poisoning, ethambutol
Optic atrophy Atrophy of the optic disc resulting from degeneration of retinal ganglion cells or their axons, chalky
white disc (primary) then dirty grey green (secondary). Waxy pallor disc (consecutive). Nasal shiting of
retinal vessels & peripapillary halo (glaucomatous optic atrophy)
Horners syndrome Cause by damage to sympathetic trunk in neck, miotic/constricted pupils (paralysis of pupillary
muscles), ptosis (paralysis of muller’s muscle), anhidrosis (reduced sweating of on face of affected
side), test- apraclonidine
RAPD Unilateral incomplete lesion of optic nerve, swinging light test- light struck on affected eye both pupils
dilate instead of constriction

ORBIT
Proptosis Forward displacement of an eyeball orbital margins, m/c overall cause is thyroid disease axial central
displacement- thyroid opthpathy, non axial- growth invading orbit from paranasal sinus
Preseptal cellulitis Actue infection of subcutaneous tissues ant. to the orbital septum, m/c type of cellulitis esp in
children, staph aureus, ocular movt ,VA and pupillary reaction are normal
Orbital cellulitis Acute infection of orbital soft tissues posterior to the orbital septum, medical emergency, staph
aureus, extraocular movt. restricted and painful, exposure keratopathy, spread to brain (v.dangerous)
Cavernous thrombosis Formation of boodclot in cavernous sinus, conjunctival chemosis, swelling of mastoid process of
temporal bone, life-threatening, staph aureus, unilateral proptosis
Thyroid eye disease, Middle aged, smoking females with HLA-DR3, (Dark Valley Kissed Sunset) dalrymple’s, von graefe’s,
graves kocher’s & stellwag’s signs, causes keratoconjunctivitis cicca, test-ultrasonography & TFT’s
 INJURY
Extra ocular foreign Very common in agricultural & industrial workers
body
Blunt trauma Closed globe injury, by ball
(contusion)
Intraocular foreign body MRI, CT, A & B scan, NO MRI, Siderosis-iron chalcosis-copper, kaiser-fleischer rings
Chemical injury Emergency; irrigation, Acids- coagulation of proteins, cornea opaque. Alkalis-saponify cell membrane
FA, penetrate deeper tissues, burn marks.
Sympathetic Bilateral granulomatous panuveitis after penetrating ocular injury, sympathizing eye is non injured
ophthalmia fellow eye developing uveitis, dalen fuhcs nodules
Blow-out fracture Object lager than eyeball, tennis ball, weakest; orbital floor & maxillary bone, diplopia, Xray (waters
view)

REFRACTION
Hypermetropia (far Parallel rays focused behind the retina when accommodation is at rest. (near object blur), asthenopic
sightedness) (eyestrain) sympts, convex lens, lasik upto 4 diopters, PRK upto 2 diopters
Myopia (near Parallel rays focused infront of the retina when accommodation is at rest (far object blur), m/c
sightedness) common, A scan for ↑axial length, concave lens, lasik upto 12 diopters, lens extraction upto 20dioptrs
Astigmatism Parallel rays cannot form single focus point, strum’s conoid- dist b/w two focal point, dislocation of
lens, cataract, keratoconus/corneal injury, surgical- limbal relaxing incision, lasik
Simple myopic One meridian focus on retina and the other infront of retina, cylindrical lens
astigmatism
Simple hypermetropic One meridian focus on retina and the other behind of retina, cylindrical lens
astigmatism
Compound myopic Both the meridians focus infront of retina, spherocylindrical lens
astigmatism
Compound Both the meridians focus behind of retina, spherocylindrical lens
hypermetropic astig.
Mixed astigmatism One meridian focus infront and one behind the retina, spherocylindrical lens
Irregular astigmatism Multiple irregular foci
Presbyopia ↓Power of refraction of lens, ↓elasticity, senile, convex lens/ reading glasses
Anisometropia Unequal refractive power of the eyes, difference > 4diopters is not tolerated, cause amblyopia if
under 9 years otherwise diplopia
Aniseikonia Different size and shape of images

SQUINT
Binocular single vision Fusion of two foveal images of an object into unified perception of single image
(BSV)
Amblyopia/lazy eye <9 years, decrease in the best corrected visual acuity, no improvement on pinhole, improved with
single words spread apart, occlusion of normal eye to encourage use of amblyopic eye
Strabismic amblyopia Most common, uniocular squint
Stimulation deprived No/reduced image formation in early life in e.g complete ptosis, any other congenital disease causing
amblyopia the same effect
Anisometropic Unequal refractive power of the eyes
amblyopia
Isometropic amblyopia Bilateral amblyopia, High refractive error > 5 diopters
Astigmatism amblyopia When astigmatism > 1 diopter
Squint Misalignment of the visual axes of eyes
AC/A ratio Accommodative convergence to accommodation ratio, normal 3:1
Congenital exotropia AC/A normal, neurological patho, angle of deviation is large, alternate fixation, surgery
Intermittent exotropia Most common, diplophotophobia- closure of one eye in bright light, horizontal diplopia, deviation
present at times and latent at others, alternate deviation,
Constant exotropia Intermittent can turn into constant
 TYPES of ESOTROPIA FEATURES TREATMENT
Congenital infantile Angle of deviation> 30dergees Surgical:
(6 months or less) Cross & alternate fixation Recession
Associated with: Resection
-dissociate vertical deviation (DVD)
-nystagmus
-inferior oblique overaction
Accommodative refractive Associated with hypermetropia Glasses
(1.5-3 years) AC/A normal
Deviation changes with changing object
distance
m/c in childhood
Accommodative non-refractive Deviation remains same with changing Bifocal glasses
object distance
↑AC/A
↓Binocular singular vision
.
Paralytic squint (non 3rd 4th 6th nerve palsies, sudden, secondary deviation greater than primary deviation, deviation not
concomitant) equal in all directions, usually trauma, nausea, vertigo, limited ext. ocular movt
Secondary deviation Position of the normal eye when the affected eye (primary) Is in position
Third nerve palsy lateral & downward deviation, LPS, MR, IR, IO are paralyzed, ptosis (LPS), pupil dilated. Pupil involving
palsy- surgical/traumatic, Edinger Westphal nucleus+ main motor, pupil sparring palsy- systemic, HTN,
DM, only main motor nucleus
Fourth neve palsy Trauma, vertical diplopia-extorsion, head tilt towards unaffected side, hypertropia-upwards, superior
oblique paralyzed
Sixth nerve palsy Horizontal diplopia, esotropia, lateral rectus paralyzed