Microbial keratitis after corneal collagen crosslinking

Several infiltrates appeared in the upper midperipheral cornea of a 29-year-old woman who had had uneventful corneal collagen crosslinking (CXL) with riboflavin and ultraviolet-A light (UVA) for the treatment of keratoconus in the right eye. Staphylococcus epidermidis keratitis was confirmed by microbiological studies, which guided treatment with topical fortified antibiotic agents. Before CXL, the best spectacle-corrected visual acuity (BSCVA) in the right eye was 20/25, the manifest refraction was -0.25 -0.25 x 125, and the anterior segment was normal under biomicroscopy. Five months after the procedure, the BSCVA was 20/22, the manifest refraction was +1.00 -2.50 x 40, and slitlamp examination revealed a mild residual haze in the upper midperipheral cornea. Collagen crosslinking with riboflavin-UVA is a minimally invasive method but traditionally requires epithelial removal, which could be a predisposing factor to bacterial keratitis.