Cataracts

A cataract is a clouding of the eye's natural lens, the part of the eye that is responsible for focusing light onto the back of the eye and adjusting the eye's focus. The lens, which is mostly made up of water and protein, can get cloudy with age if the protein begins to clump together. This clump of protein is called a cataract.

Cataracts are classified in three ways: nuclear, cortical or subcapsular. In a nuclear cataract, the cloud forms in the nucleus, or center of the lens, due to the normal aging process. In a cortical cataract, the cloud forms in the lens cortex and gradually extends to the center. This is often found in people with diabetes, a group thought to be at high risk for developing cataracts. Thirdly, the subcapsular cataract forms at the back of the lens, and is often founded in diabetics, people with high farsightedness or retinitis pigmentosa, or people taking high doses of steroids.

Cataracts develop slowly, with symptoms worsening over time. They may begin as a slight blurring or increased sensitivity to light. During this stage, eyeglasses can temporarily improve vision. Eventually, however, cataracts will cause serious damage to vision, requiring a simple surgery. More than 1.5 million cataract surgeries are performed each year, with nine out of 10 people regaining good vision, between 20/20 and 20/40.