A cataract is a clouding of part or all the lens inside the eye. This clouding interferes with light reaching the retina at the back of the eye, resulting in a general loss of vision. Causes include aging, long-term exposure to the sun's ultraviolet radiation, injury, disease, and inherited disorders. If the eye is healthy, a cataract can be surgically removed. Usually, an intraocular lens implant is inserted in the eye, and vision is restored. Cataract surgery has a high success rate in otherwise healthy eyes. However, cataract surgery is not always possible for people who also have other eye diseases. These people may require low-vision rehabilitation to maximize their remaining vision.