Microbial keratitis in lattice corneal dystrophy: microsporidia as a new cause

A patient in his sixth decade presented to us with redness, pain and a deterioration of vision in his left eye. He had previously been diagnosed with lattice corneal dystrophy (LCD). He was diagnosed with microbial keratitis, and mixed infection was confirmed on culture (bacteria and fungus) with a protracted healing period before resolution of keratitis. He presented 2 years later with similar issues in the same eye and was noted to have a second episode of microbial keratitis, with microsporidia spores noted on gram, potassium hydroxide and calcofluor white stains. He was diagnosed with microsporidial stromal keratitis and underwent therapeutic penetrating keratoplasty. Unfortunately, he suffered a recurrence of microsporidial keratitis following surgery with eventual transplant failure. Microsporidia as an infection in LCD has, to our knowledge, not been previously reported. We aim to discuss microsporidial infection and recurrent microbial keratitis in the setting of LCD.