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 fl uid 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 defi ned 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 signifi cantly 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. [J Refract Surg. 2011;xx(x):xxx-xxx.] doi:10.3928/1081597X C ontact lens storage cases are a potential source and reservoir of bacteria, fungi, and amoebae. Several microbiological studies in different parts of the world have indicated consistently high rates of bacterial contamination in the contact lens cases of asymptomatic patients, ranging from 24% to 87%. 1-19 Although corneal refractive surgeries are relatively safe procedures, infection can be a rare but sight-threatening complication. The reported rates of infection after LASIK range from 0% 20 to as high as 1.2%. 21 Among the reasons leading a contact lens wearing patient to seek refractive surgery, inconvenience in wearing contact lenses was found to be either the fi rst 22 or second most important reason after the desire for improvement of unaided vision. 23 This inconvenience, to some degree, is due to the strict hygiene demands required of the patient when dealing with contact lenses and contact lens storage cases. 22 It is therefore reasonable to assume that patients’ diffi culties may have an effect on adhering to the strict hygiene rules, leading to suboptimal hygiene and possible high rates of contact lens and storage case contamination. To the best of our knowledge, no study in the literature has examined the rates of contamination of contact lens cases in refractive surgery candidates. Furthermore, all previous studies regarding contamination of contact lens storage cases examined the bacterial and fungal contamination using only the traditional method of culturing, ie, blood agar, chocolate agar, and special media for fungi such as Sabouraud agar, and not