Hydrogen peroxide damage to human corneal epithelial cells in vitro. Implications for contact lens disinfection systems.

We investigated the cytotoxicity of hydrogen peroxide by exposing primary cell cultures of human corneal epithelium to a single dose of this agent at concentrations ranging from 30 to 100 ppm. Hydrogen peroxide, at a concentration as low as 30 ppm, caused cell retraction as well as cessation of cell movement and mitotic activity. Formation of membranous vesicles preceded cell death that occurred by 7 to 8 hours after exposure to 30 ppm. With a concentration of 50 ppm, normal cell activity ceased almost instantaneously. Numerous surface vesicles formed by 1.5 hours of exposure, and the cells died by 4 to 5 hours. Higher concentrations of hydrogen peroxide (70 to 100 ppm) caused cell death within a few minutes. Because neutralization of hydrogen peroxide and patient compliance are critical in the proper use of hydrogen peroxide-based contact lens disinfection systems, users will be well served if the long-term effects of residual peroxide on the cornea are subjected to continued study.