Corneal anesthesia induced by soaps and surfactants, lack of correlation in rabbits and humans

Five commonly marketed bath and facial soaps and four commercially available hair shampoos were studied for their anesthetic effect on human and rabbit corneas. These compounds all produced anesthesia comparable to that induced by tetracaine hydrochloride 0.5 percent but lasting several hours longer in rabbits. None of the soaps or shampoos produced corneal anesthesia in humans. Studies of corneal anesthesia in rabbits may not be extrapolated to the human eye.