Cataracts appear because of a buildup of protein in the lens of the eye that makes it cloudy. Since newer cells of the lens form on the outside, the older lens cells are pushed back and condensed, resulting in clouded vision.
The lens is the part of the eye that bends light so that it can focus on the retina. When the protein buildup causes the lens to be cloudy, it blocks some of the incoming light, resulting in some loss of vision.
The development cataracts is commonly linked to age. The older one gets, the greater chance one has at developing them. Some people also develop cataracts as a result of injury to the eye. The condition has also been reported to occur as a result of diabetes. Other risk factors that increase the chance of developing cataracts are exposure to pollutants or other toxic substances, exposure to cigarette smoke, taking certain medications and heavy alcohol use.
Sometimes the loss of vision due to cataracts can be treated by simply adjusting a person's prescription glasses or adding bifocals. However, if none of the above options work, surgical replacement of the lens with an artificial one is often recommended. The surgery is generally very effective, with many people reporting improved vision.