Evaluation of contamination of used disposable contact lenses by Acanthamoeba

Purpose: The purpose of this study was to evaluate the contamination of used disposable soft contact lenses with Acanthamoeba. Methods: We evaluated 51 consecutive disposable soft contact lens wearers in a prospective study. Before their check-up visits, patients were offered a free new contact lens in exchange for donating their old one. The used contact lenses (n=102) were then removed and placed in culture medium for Acanthamoeba. We subsequently investigated patterns of wear and hygiene habits. Results: The mean age of this population was 32.6±11.0 years. The average time of disposable soft contact lens wear was 13.7 hours per day. The contact lenses were disinfected daily with commercial solutions. Twenty-five (49.0%) subjects did not clean their lens cases properly. Acanthamoeba was not isolated from any of the 102 lenses. Conclusions: There were no cases of Acanthamoeba contamination in a small population of disposable soft contact lens wearers who regularly disinfected their lenses with standard commercially available contact lens solutions.