Posterior infectious crystalline keratopathy with Staphylococcus epidermidis

Two cases of infectious crystalline keratopathy located in the posterior stroma after penetrating keratoplasty are presented. Topical steroids and suture removal were risk factors in both cases. In the first case, a moderate anterior chamber reaction was present. Crystalline infiltrates persisted on topical and systemic steroid therapy. In the second case, deep corneal ulceration, hypopyon, and vitreitis were noted. A vitreous aspirate showed rare gram-positive cocci in pairs. The corneal ulceration and crystalline keratopathy persisted despite intravitreal and topical antibiotics. Therapeutic penetrating keratoplasty was performed in both cases. Staphylococcus epidermidis sensitive to vancomycin was isolated from corneal tissue. Light microscopy documented aggregates of gram-positive bacteria anterior to Descemet's membrane, with an overlying keratitis. Electron microscopy in the second case showed all bacteria within stromal keratocytes. No clinical recurrence was seen using topical vancomycin. As demonstrated in the cases presented, infectious crystalline keratopathy can occur exclusively in the deeper layers of the cornea. Isolation of S. epidermidis, associated inflammation, and intraocular spread of organisms are rare findings.