All About Cataracts

A cataract is a clouding of the eye's lens.  The lens lies behind the iris and the pupil. The lens functions much like a camera lens, focusing light onto the retina at the back of the eye. The lens also adjusts the eye's focus.  The lens is responsible for letting us see things clearly both up close and far away.

The lens content is mostly water and protein. The protein is arranged in a precise way that keeps the lens clear and lets light pass through it. With added age, some of the protein may start to clump together.  These clumps may start to cloud a small area of the lens. These clouds or clumps of protein is a cataract.  Over time, these clouds may grow larger and cover more of the lens, thus making it harder to see.

There are three categories of cataracts: nuclear, cortical or subcapsular.

Nuclear Cataract: The most commonly seen form of cataracts is the nuclear cataract. This cataract forms in the nucleus, the center of the lens, and is due to natural aging changes.

Cortical Cataract: A cortical cataract forms in the lens cortex. It gradually extends its spokes from the outside of the lens towards the center. Many diabetics develop cortical cataracts.

Subcapsular Cataract: A subcapsular cataract begins at the back of the lens. People with diabetes, high farsightedness, retinitis pigmentosa or those taking high doses of steroids may develop a subcapsular cataract.