No one knows what really causes them. However, we do know that the clouding of the lens comes from a chemical modification within the eye which can be related to aging, heredity, trauma or illness. This may be due to advancing age or it may be the result of heredity, an injury or a disease. Excessive exposure to ultraviolet radiation present in sunlight, cigarette smoke or the use of certain medications are also risk factors for the development of cataracts. Cataracts usually develop in both eyes, but often at different rates.
