Although tests on stratified cells are capable of detecting damage caused by H2O2 in culture medium, residual H2O2 in neutralized ophthalmic formulations had no effect on stratified cells in vitro. These data suggest that H2O2, used appropriately, is a safe disinfectant. Data comparing monolayer and stratified cultures suggest that monolayers are more sensitive to peroxide damage and that the effects of neutralized formulations on stratified cells may better predict the intact corneal epithelial response.