Ultrastructural alterations in the endothelium in a patient with topical anesthetic abuse keratopathy

A 40-year-old patient frequently self-administered topical oxybuprocaine drops for approximately 7 days after bilateral ultraviolet-light keratitis. Initially, he developed bilateral chronic epithelial defects with diffuse stromal infiltration and edema. After a protracted initial healing period, the patient underwent a penetrating keratoplasty in one eye because of significant corneal scarring. Pathologically, the corneal button revealed scarring and thinning of the central stroma. Results of scanning electron microscopy showed endothelial polymorphism, focal endothelial necrosis, and numerous filamentous processes emanating from abnormally enlarged intercellular gaps. Results of transmission electron microscopy showed markedly attenuated to absent apical cell attachments at the endothelial intercellular junction. Abuse of oxybuprocaine appears to produce irreversible damage to the apical cell attachments at the level of the corneal endothelial cells.