Case of unilateral pellucid marginal corneal degeneration progressing to corneal perforation with keratoconus in contralateral eye

PURPOSE: To report our findings in a case of pellucid marginal corneal degeneration (PMCD) in the left eye and keratoconus (KC) in the right eye, and to review earlier cases of PMCD and KC. OBSERVATIONS: A 45-year-old woman visited our hospital with a complaint of reduced vision in her right eye. She was predisposed to allergies since childhood and had a habit of rubbing her eyes. Based on the results of the corneal topographic study, we diagnosed her with KC in the right eye and PMCD in the left eye. We prescribed a rigid, gas permeable contact lens and treated her allergic conjunctivitis with ocular medications. Three years after her initial visit, she developed a corneal perforation in the left eye. The perforation was closed by conservative treatment consisting of therapeutic soft contact lens wear. One year after the cornea healed, the corneal astigmatism in the left eye was about one-half of what it was before the corneal perforation. Her corrected visual acuity improved to 1.0 with conventional spectacles. CONCLUSIONAND IMPORTANCE: We found a difference in the progression of KC and PMCD even when they occurred in same individual. We suggest that the atopic predisposition, which is considered a risk factor for acute hydrops in KC, to be a risk factor for acute hydrops and corneal perforation in eyes with PMCD.