• We examined the adherence of a human corneal isolate of Pseudomonas aeruginosa to unused rigid gas-permeable and hydrogel contact lenses. Adherence to rigid gas-permeable lenses was greater than the adherence to hydrogels. The lower incidence of microbial keratitis associated with rigid gas-permeable lenses, as compared with hydrogel lenses, may be attributed to the more rigorous cleaning and disinfection possible for rigid gas-permeable lenses and/or patient noncompliance with complicated disinfection systems used with hydrogel lenses.