Prolonged wound healing following perforating keratoplasty

Nasal hyperbaric respiration devices used at night to counteract sleep apne a may represent a concealed cause of delayed superficial wound healing foll owing perforating keratoplasty. We report the cases of two patients whose r espirators produced a continuous flow of pressurized air (nCPAP) onto the o perated eyes, leading to conjunctival hyperemia, recurrent corneal erosion, infiltration of the puncture track and the cornea, and superficial punctat e keratopathy. Microbiological investigation revealed no clearly identifiab le pathogens. Healing improved consistently only after the pressurized air system had been modified so that no air escaped from the nostrils and the p atients had been instructed in disinfection of the moisturizing system.