Microbiology of contact lens-related keratitis

We reviewed 397 cases of microbial keratitis examined at the Massachusetts Eye and Ear Infirmary, Boston, MA, U.S.A., from January 1982 through December 1985. Of these, 136 cases (34%) were related to contact lens use. Extended-wear contact lenses were used by 107 (79%) of these patients. Cosmetic contact lenses accounted for 59 (44%) of lens-related cases, aphakic contact lenses 44 (32%), therapeutic (bandage) contact lenses 33 (24%). Fifty-three microbial keratitis cases associated with contact lens wear were culture-positive: 28 (52%) were gram-positive, and 19 (36%) were gram-negative. Mixed cultures, fungi, and Acanthamoeba accounted for two cases (4%) each. Pseudomonas aeruginosa was specifically associated with cosmetic soft contact lens use.