A cataract is the clouding of the lens of the eye. This prevents the normal passage of light to the retina, creating either a blurry image or bothersome glare. Cataracts are a normal part of the aging process. Trauma to the eye, ultraviolet light, and diseases that affect the eye, such as diabetes, can also cause cataracts.

People with progressed cataracts often describe the sensation as looking through a piece of wax paper. A cataract may make light from the sun or a lamp seem too bright, causing glare. Colors may not appear as bright as they once did. However, most cataracts develop so slowly that people usually don’t realize that their color vision has markedly deteriorated. Oncoming headlights may cause uncomfortable glare at night, making driving more difficult