Diagnosis of Microsporidial Keratitis by Confocal Microscopy and the Chromatrope Stain

Purpose To illustrate the value of confocal microscopy and chromatrope stain in the diagnosis of microsporidial keratitis. Methods In vivo confocal microscopy was performed on a man with the human immunodeficiency virus who had severe bilateral epithelial keratitis refractory to topical antibacterial medications. The results were compared to conjunctival scrapings stained with the chromatrope-based Weber stain. Results Confocal microscopy demonstrated many small, intraepithelial opacities of the corneal epithelium, which were suggestive of Microsporidia. Results of the chromatrope stain of conjunctival scrapings confirmed the diagnosis of microsporidial keratitis. Conclusions Rapid diagnosis allowed prompt initiation of topical fumagillin, which permitted rapid, long-term control of the symptoms of microsporidial keratitis.