We report 13 cases of corneal ulcers caused by gram-negative bacteria. These cases occurred in aphakic eyes wearing hydrophilic contact lenses on an extended-wear basis. The risks for infection in the elderly aphakic eye with extended-wear hydrophilic lenses are increased by delay in removal of the lens. Caution in the use of these lenses is urged. The ability of either the patient or an attendant to remove the lens as soon as redness, diminished vision, or pain presents itself is essential in minimizing the risks for serious infection.