Cataract This information was developed by the National Eye Institute to help patients and their families search for general information about cataracts. An eye care professional who has examined the patient's eyes and is familiar with his or her medical history is the best person to answer specific questions. Table of Contents * Cataract Defined What is a cataract? What is the lens? Are there other types of cataract? * Causes and Risk Factors What causes cataracts? How can cataracts affect my vision? When are you most likely to have a cataract? Who is at risk for cataract? What can I do to protect my vision? * Symptoms and Detection What are the symptoms of a cataract? How is a cataract detected? * Treatment How is a cataract treated? What are the different types of cataract surgery? What are the risks of cataract surgery? Is cataract surgery effective? What happens before surgery? What happens during surgery? What happens after surgery? Can problems develop after surgery? When will my vision be normal again? What can I do if I already have lost some vision from cataract? * Current Research What research is being done? * More Information Eye Health Organizations and more. Cataract Defined What is a cataract? A cataract is a clouding of the lens in the eye that affects vision. Most cataracts are related to aging. Cataracts are very 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. It cannot spread from one eye to the other. Image of the eye What is the lens? The lens is a clear part of the eye that helps to focus light, or an image, on the retina. The retina is the light-sensitive tissue at the back of the eye. In a normal eye, light passes through the transparent lens to the retina. Once it reaches the retina, light is changed into