What Is a Cataract?
A cataract is a clouding of the lens in the eye. By age 80, more than half of all Americans either have a cataract or have had cataract surgery. The lens is a clear part of the eye that helps to focus an image on the retina. The lens must be clear for the retina to receive a sharp image. If the lens is cloudy from a cataract, the image will be blurred.
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. 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.
A cataract needs to be removed only when vision loss interferes with everyday activities, such as driving, reading or watching TV. You and your doctor can make this decision together.
Source: National Eye Institute