Corneal dystrophy refers to a set of hereditary eye diseases characterized by pathological changes to the cornea. Depending on which part of the cornea is affected, the disease can be divided into four groups – epithelial dystrophy, Bowman membrane dystrophy, stromal dystrophy or endothelial dystrophy. Corneal dystrophies can cause aches, photophobia, decreased vision, and sometimes a permanent feeling of something unfamiliar in the eye. Inconvenient stabbing pain usually starts during sleep, but subsides within a few hours. For some types of corneal dystrophy, contact lens wear is not an option.