Delayed mustard gas keratitis: clinical course and in vivo confocal microscopy findings.

PURPOSE To report the detailed clinical and in vivo confocal microscopic findings in a patient with delayed-onset mustard gas keratitis observed 20 years after initial exposure. METHODS A 38-year-old man who was exposed to mustard gas in Iraq at the age of 19 years was examined after presenting with ocular symptoms 17 years after initial recovery from the exposure. Slit-lamp biomicroscopy, corneal topography, and in vivo confocal microscopy were performed on both corneas. RESULTS The clinical symptoms were consistent with a delayed form of mustard gas keratitis, although the patient had clear central corneas and good visual acuity. Confocal microscopic findings included evidence of epithelial abnormalities, necrotic changes in the anterior stroma, subbasal and anterior stromal nerve proliferation, and deep stromal keratocyte activation. CONCLUSIONS In vivo confocal microscopy revealed persistent morphologic abnormalities in the anterior stroma of both corneas 20 years after initial exposure to mustard gas. The detection of a population of dendritic cell bodies in the central epithelium and evidence of keratocyte activation and migration in the deep stroma indicated the presence of ongoing subclinical processes.