Cataract

A cataract is a clouding of the eye's crystalline lens, which lies behind the iris and the pupil. The lens helps us focus on objects both near and far away. Early in the development of a cataract, near-sightedness is a common early consequence of a cataract. If left untreated a cataract can cause complete blindness. There are a wide variety of causes; treatment involves a surgical procedure.