Contamination of contact lens storage cases of asymptomatic refractive surgery candidates.

PURPOSE

To examine the rates of contamination of contact lens storage cases of refractive surgery candidates and compare the growth yields of the traditional method of culturing and a broth-based method.

METHODS

Thirty contact lens storage cases of 16 asymptomatic refractive surgery candidates were studied. Samples from the lens storage case fluid were inoculated into Bactec Peds Plus F broth (Becton Dickinson) and also directly onto blood agar, chocolate agar, and Sabouraud dextrose agar ("traditional method"). Another sample was processed for amoebal contamination. The rate of contamination of cases and the types of pathogens were evaluated for the broth-based and traditional culturing methods. Correlation between right and left storage cases of the same patient was defined as contamination of the two compartments with the same pathogen or pathogens. To avoid statistical bias, only one compartment was included in the study for these patients.

RESULTS

Four storage cases were omitted due to growth correlation between right and left storage cases. Of the remaining 26 storage cases, 16 (61.5%) were found to be contaminated using the broth-based method and 10 (38.5%) using the traditional method (P=.011). High contamination rates were observed regardless of the type of disinfecting solution or type of contact lens used.

CONCLUSIONS

The broth-based method had significantly greater culture yield than the traditional method. The high rates of contamination of contact lens storage cases of refractive surgery patients may put this cohort at greater risk than non-contact lens wearing candidates for developing postoperative infections.