Corneal dystrophy is a condition in which the cornea, the clear covering of the eye, becomes less clear because of a buildup of cloudy material. There are over 20 kinds of corneal dystrophy, but they all share certain traits. Corneal dystrophies are usually inherited, affect both eyes equally, are not caused by injury, get gradually worse with time, and are not related to any other kind of disease. Symptoms can range from no vision impairment to severe vision impairment. Some forms of corneal dystrophy can also cause pain. The early stages of corneal dystrophy can be treated with special eyedrops, but once there is severe vision impairment, surgery and corneal transplant may be necessary.