Contamination of disinfection solution bottles used by contact lens wearers.

We investigated the contamination of disinfection solution bottles after 2 weeks of patient use. Forty-four subjects participated in the study and each used three soft lens care systems (cross-over study). The order in which the three care systems were dispensed was randomized to eliminate systematic bias. Sixteen subjects used only one of the systems (disinfection solutions) over three consecutive 2-week periods (reliability study). Contamination of the disinfection solution bottles occurred in 12 of the 180 bottles sampled (7%), and the level of contamination of these bottles ranged up to 10(5) colony forming units per milliliter. A wide range of microorganisms was identified in these positive samples, many of which were potential ocular pathogens. None of the subjects in the study (n = 60) showed contamination in more than one of the three solution bottles sampled, suggesting that the phenomenon was not strongly patient specific. The rate of contamination of disinfection solution bottles was not influenced by contact lens wearing experience (i.e., familiarity with care procedures), by the time of year (season) at which the samples were collected, or by the subjects' compliance with hand washing. However, among the 44 subjects in the cross-over study, the rate of contamination of disinfection solution bottles was influenced by the type of disinfection solution.