is a clouding of the eye’s naturally clear lens. Most cataracts appear with advancing age. The most important factor in cataract formation is increasing age, but there are additional factors, including smoking, diabetes, and excessive exposure to sunlight. Cataract is the leading cause of blindness in the world, and affects nearly 20.5 million Americans age 40 and older. By age 80, more than half of all Americans develop cataract. Cataract is sometimes considered a conquered disease because surgical treatment that can eliminate vision loss due to the disease is widely available. The cataract is removed surgically and a plastic lens, called an implant, is placed in the eye restoring normal sight.