Effectiveness of Contact Lens Disinfectants After Lens Storage

PURPOSE: To determine the effectiveness of multipurpose contact lens solutions after incubation with lenses for one week. METHODS: Five multipurpose solutions, three lots each, were preincubated with contact lenses for one week. The solutions were removed and one of three microbes was added to a final concentration of l x l0(6)/mL. The inoculated solutions were incubated for 4 and 6 hours; aliquots were then neutralized, serially diluted, and plated. Plate counts were used to determine the approximate number of organisms that were killed effectively by the contact lens solution. RESULTS: Of the five solutions tested, only OPTI-FREE Express maintained full effectiveness after preincubation with lenses. The other solutions were effective only with Fusarium solani after the preincubation period. CONCLUSIONS: We propose that the active component was sufficiently reduced by absorption or inactivation during storage with contact lenses such that it was rendered effective only for F. solani and was no longer concentrated enough to be effective with the bacterial species.