Map-Dot-Fingerprint Dystrophy
This dystrophy occurs when the epithelium’s basement membrane develops abnormally (the basement membrane serves as the foundation on which the epithelial cells, which absorb nutrients from tears, anchor, and organize themselves). When the basement membrane develops abnormally, the epithelial cells cannot properly adhere to it. This, in turn, causes recurrent epithelial erosion, in which the epithelium’s outermost layer rises slightly, exposing a small gap between the outermost layer and the rest of the cornea.
Epithelial erosions can be a chronic problem. They may alter the cornea’s normal curvature, causing periodic blurred vision. They may also expose the nerve endings that line the tissue, resulting in moderate to severe pain lasting as long as several days. Generally, the pain will be worse on awakening in the morning. Other symptoms include sensitivity to light, excessive tearing, and foreign body sensation in the eye.