Spontaneous corneal perforation in a patient with unusual unilateral pellucid marginal degeneration.

A 56-year-old man presented with acute loss of vision and tearing in his left eye. Slitlamp examination demonstrated peripheral corneal edema extending between the 2 and 6 o'clock positions as well as a perforation located inferiorly. The right eye was unremarkable. An emergent crescentic lamellar keratoplasty was performed. The patch graft remained clear during the 30-month follow-up, and visual acuity improved significantly. No changes occurred in the right eye. This case represents an unusual, unilateral corneal ectatic disorder, most likely pellucid marginal degeneration.