CATARACT
Cataract is a clouding of the lens or any opacity within the lens which leads
to a decrease in vision.
Aetiology :-
Degeneration and opacification of forms lens fibres
Formation of aberrant lens fibres
Deposition of other materials in their space
Hydration
Denaturation of lens proteins
Sclerosis
Risk Factors :-
Heredity
Age UV radiation
Dietary deficiencies of vitamins A, C, E
Severe diarrhoea
Diabetes
Smoking
Corticosteroids
General Symptoms :-
Decreased vision
Decreased contrast sensitivity
Refractive error
Monocular diplopia and coloured halos
Glare
Change in colour values
Classification of Cataract :-
A. CONGENITAL AND DEVELOPMENTAL CATARACT :
1. Blue-dot cataract
Tiny bluish white opaque spots scattered all over the lens.
No visual disturbance.
FOUNDER: DR. HARSH PRAJAPATI 1
2. Coronary cataract
Club shaped opacities in the peripheral part of the cortex, arranged
like a corona or crown.
3. Capsular or polar cataract
a. Anterior capsular cataract –
It involves the central part of the anterior capsule and the adjoining
superficial-most cortex.
b. Posterior capsular cataract –
It is a very common lens anomaly and consists of a small circular
circumscribed opacity involving the posterior pole.
4. Sutural cataract
Tiny opaque dots situated in the Y sutures of the lens.
No visual disturbance.
5. Coralliform cataract
Minute opacities situated in the central area of the lens in the form
of a coral
No visual disturbance.
6. Floriform cataract
The opacities are annular in shape, arranged like the petals of flower
and situated in the axial part of the lens.
No visual disturbance.
7. Central cataract
The nucleus of the lens shows opacity.
The opacities may be granular when there is no visual disturbance or
the whole of the nucleus may be opaque associated with visual
disturbance.
8. Lamellar or zonular cataract
This type of cataract is characterised by the opacity of one zone of
the lens fibres, while the rest of the lens, including the nucleus,
remains clear.
9. Total cataract
The entire lens is opaque.
All these cataracts are generally unilateral or bilateral.
FOUNDER: DR. HARSH PRAJAPATI 2
Diagnosis :-
Pupil must be well dilated with one percent atropine ointment.
The lens must be examined with a torch and a loupe or with the help of a
slit-lamp, for any evidence of opacity.
Management :-
Ocular examination –
It should be carried out with special reference to density and
morphology of cataract.
Special test like –
Fixation reflex, forced choice preferential looking test, visually evoked
potential (VEP), etc. also provide useful information.
Surgical Procedure :-
Childhood cataract can be dealt with anterior capsulotomy, irrigation of
the lens matter, lensectomy.
In case of membranous cataract, membrane has to be removed with a
capsule forceps, through akeratome incision through the limbus.
B. ACQUIRED CATARACT :
1. Senile cataract
Usually bilateral but develops earlier in one eye.
Genetic influence is marked. In hereditary cases the cataract
appears at earlier ages in subsequent generations.
55% of the total blindness is due to senile cataract.
2. Traumatic cataract
By mechanical trauma
By chemical trauma
By radiational trauma
Electric cataract
3. Endocrine cataract
i. Diabetic cataract
It occurs in young diabetics of a severe type.
FOUNDER: DR. HARSH PRAJAPATI 3
The snow-flake like opacities appear in the cortex and the entire
lens becomes completely opaque very soon.
ii. Parathyroid cataract
If the parathyroid are removed accidentally during operation on
the thyroid gland, cataract develops within 2-3 months.
4. Cataract due to systemic diseases
I. In Mongolian idiocy –
The cataract develops as punctate opacities in the superficial
cortex.
II. In myotonic dystrophy –
Fine dust like opacities interspersed with iridescent spots appear
in the superficial cortex.
III. Dermatogenous cataract –
It develops in cases of severe dermatitis particularly in the young.
5. Complicated cataract
The cataract is due to disturbance of the metabolism of the lens,
caused by diffusion of toxins through the capsule.
6. Cataract due to drugs
Cataract due to corticosteroids.
If the drug is discontinued the progress of the cataract stops.
Treatment of cataract :-
A. Non-surgical treatment –
Treatment of cause of cataract
Measures to delay progression
Measures to improve vision in the presence of incipient and improve
cataract
B. Surgical treatment –
Visual improvement
Medical indications
Cosmetic indications
FOUNDER: DR. HARSH PRAJAPATI 4
FOUNDER: DR. HARSH PRAJAPATI 5
