The lens works with the transparent cornea, which covers the eye's surface, to focus light on the retina at the back of the eye. When the lens becomes cloudy, or cataractous, light cannot pass to the retina properly, and vision is blurred and decreased. Although cataracts result from many conditions, the most frequent cause is the natural aging process. Other causes may include injury, chronic eye disease, and other system-wide diseases such as diabetes. More than half the people over age 65 have some degree of cataract development.
Cataracts can take from a few months to several years to develop.
Sometimes, the cataract stops developing in its early stages, and vision is only slightly decreased. But if it continues to develop, vision is impaired, and treatment is necessary. Surgery to remove the diseased lens is the only effective treatment for cataract. Neither diet nor medications have not been shown to stop cataract formation. Cataract surgery is now a frequently performed operation in most parts of the world.