DefinitionA cataract is a cloudy area in the lens of the eye.This article focuses on cataracts in adults. For information on cataracts in children, see: Congenital cataractsAlternative NamesLens opacityCauses, incidence, and risk factorsThe lens of the eye is normally clear. If the lens becomes cloudy, the condition is known as a cataract. Rarely, cataracts may be present at or shortly after birth. These are called congenital cataracts.Adult cataracts usually develop very gradually with advancing age and may run in families. They develop slowly and painlessly, and vision in the affected eye or eyes slowly gets worse.Cataracts develop more quickly if there are some environmental factors, such as smoking, exposure to other toxic substances, and exposure to excessive ultraviolet light or sunl