What Are Cataracts?

What Are Cataracts?
A cataract is simply the clouding of the lens in the eye. When the lens becomes cloudy, the flow of light is distorted and the picture formed on your retina becomes dim or blurry.

Cataracts are common in older people. By age 80, more than half of all Americans either have a cataract or have had cataract surgery. A cataract can occur in either or both eyes. However, it cannot spread from one eye to the other.

In addition to the obvious problems of reduced vision, the visual disability associated with cataracts can have a significant impact on the risk of falls and fractures, your quality of life, and possibly even mortality.

Understanding the Lens
The lens lies behind the iris and the pupil. It works much like a camera lens. It focuses light onto the retina at the back of the eye, where an image is recorded. The lens also adjusts the eye's focus, letting you see things clearly, both up close and far away.

The lens is made of mostly water and protein. The protein is arranged in a precise way that keeps the lens clear and lets light pass through it.

In a normal eye, light passes through the transparent lens to the retina. Once it reaches the retina, light is changed into nerve signals that are sent to the brain. But as we age, some of the protein may clump together and start to cloud a small area of the lens. This is a cataract. Over time, the cataract may grow larger and cloud more of the lens, making it harder to see.