Performance of contact lens disinfecting solutions against Pseudomonas aeruginosa in the presence of organic load

Abstract

Purpose: Contact lens wearers can become noncompliant with lens disinfection procedures. The purpose of this study was to evaluate multipurpose contact lens disinfecting solutions in the presence of organic soil.

Methods: OPTI-FREE EXPRESS and three products preserved with polyhexamethylene biguanide (PHMB) were inoculated with three strains of Pseudomonas aeruginosa in organic soil. Surviving bacteria were counted at various time points, using the ISO 14729 standard method.

Results: Results indicated that OPTI-FREE EXPRESS was efficient in the presence of organic soil and achieved a reduction of almost 6 log. The other products were less effective under the test conditions and failed to achieve 3-log reduction of the bacteria. These products also seemed to lose activity after time, allowing surviving bacteria to multiply. Conversely OPTI-FREE EXPRESS maintained high activity for the entire 72 hours of the study.

Conclusions: The results indicate that OPTI-FREE EXPRESS would remain highly efficient in the case of noncompliance with disinfection procedures.