What is cataract?

Cataract is the condition in which the eye lens has gone opaque. The lens has the ability to focus the light on the retina. When it goes opaque, light is no longer conducted in an orderly manner and the eye sees images as diffuse hazy pictures.

How is the human lens designed?

To understand how the cataract really forms, it is important to know about the human lens. It consists of a central, harder, nuclear zone (like the core of an onion) surrounded by layers of soft cortical material like the skin of an onion. The whole is held in an envelope termed the capsule.

The lens is suspended in the eye behind the pupil by tiny strings or zonules, very much like curtain suspended from curtain hooks.

What are the types of cataract?

Cataracts are essentially of three types:

(A) Developmental cataract

(B) Senile cataract

(C) Acquired cataract

What are developmental cataracts?

These are cataracts in which some defect during growth of the child, hereditary, nutritional or inflammatory, has affected the normal growth of the lens and has led to loss of its transparency.

There types of cataract are seen either at birth or develop soon after, though their development may be delayed, even to the age of ten years.

Late onset of these types of cataract in a seemingly normal person is one of the reasons for having regular eye checks in infancy.

What is senile cataract?

Senile cataract occurs due to degenerative changes in the lens in old age.

This is the classic cataract which we see and speak about often. Senile cataracts are:

(A) Cortical or white soft cataracts

(B) Nuclear or brown hard cataracts

In the earlier stages, due to the hardening of the lens and thus greater refracting or focusing power, myopia tends to develop or increase. This is not true myopia and should cause no alarm as it is quite harmless and only entails a change of glasses.

What are acquired cataracts?

These are cataracts which occur either due to injury to the eye or following inflammation in the eye. They can also occur by excessive exposure to infra-red heat, X-rays, ultrasonic waves or microwave radiation.

Various diseases in the body, typically diabetes and parathyroid deficiency, can also cause cataracts.

Dustin Flores

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