Superior pellucid marginal corneal degeneration with hydrops.

Pellucid marginal corneal degeneration is a bilateral corneal ectasia characterized by a band of clear thinning that runs approximately 1 to 2 mm inside and concentric to the inferior limbus.1The uninvolved cornea protrudes centrally, overhanging the area of thinning, and remains clear and of normal thickness.1To date, to our knowledge, superiorly located hydrops has been reported only in Terrien's marginal corneal degeneration.2We report 2 cases with the characteristics of pellucid marginal degeneration, except that the thinning occurred only superiorly. In addition, the first patient we describe developed hydrops in the superior cornea of one eye. Report of Cases. Case 1 A 62-year-old black man was seen with a 4-week history of sudden onset of pain, photophobia, and decreased visual acuity in his left eye. His medical history was unremarkable, and his family history included a son with "bad astigmatism." The best-corrected visual acuity was