The differential diagnosis of Descemet's tears (Haab's striae) and posterior polymorpous dystrophy bands. A clinicopathologic study.

Band-like structures, clinically similar to Haab's striae, occur in posterior polymorphous dystrophy (PPMD) and are often confused with them. The difference in clinical appearance based on difference in histopathology allows a clear differentiation. The edge of Haab's striae are thickened, curled, and secondarily proliferate Descemet's membrane, while the area between the edge is thin and smooth. Posterior polymorphous dystrophy bands are the exact opposite. The band is a thickening of Descemet's membrane between the edges with thinner, more normal Descemet's membrane outside of them. PPMD bands may be associated with typical vesicles or appear as the only sign of dystrophy, even in the eyes of patients with a known family history.