A cataract is the loss of transparency of the crystalline lens inside the eye. This causes a disruption of light transmission to the back of the eye (retina). Vision through a cataract is like trying to see through a foggy window.
Cataracts become more common as people age. Twenty-three percent of those over 75 have some degree of cataract. Younger people may also develop cataract because of injury or even birth defects.
Chemical changes in the protein material of the lens cause a yellowish or brownish discoloration. These changes are thought to be part of the normal aging process, but other factors, such as poor nutrition, certain drugs, inherited tendencies and disease may also have an affect.
Treatment of cataract involves the replacement of the cloudy lens with a clear implant, through surgery. The decision to have surgery is based on the level of vision impairment and its impact on a person's activities, as well as the level of vision that can be restored. Visual restoration is determined in large part by the health of the retina, which is thoroughly evaluated prior to surgery.
Because there is growing evidence that exposure to ultraviolet light (sunlight) and cigarette smoking may speed a cataract's development, protecting the eyes from sunlight and not smoking are sound preventive measures.