The comparison of antimicrobial effectiveness of contact lens solutions

The aim of this study was to compare the effects of widely used multipurpose contact lens solutions against Staphylococcus aureus and Pseudomonas aeruginosa, in addition to cystic and trophozoite forms of Acanthamoeba castellanii and A. polyphaga, that cause microbial keratitis.

Three multipurpose solutions were tested: SOLO-care, ReNu, and Opti-Free Express. The test solutions were challenged with P. aeruginosa (ATCC 27853) and S. aureus (ATCC 2913) based on the ISO stand-alone and regiment test procedure for disinfecting products, A. polyphaga (ATCC 30871) and A. castellanii (1501/1A) cystic and trophozoite forms. Multipurpose solutions were sampled for surviving microorganisms at manufacturer's minimum recommended disinfection time. The number of viable organisms was determined, and log reductions were calculated.

ReNu and SOLO-care resulted in a reduction greater than the required mean 3.0 logarithmic reduction against S. aureus, and SOLO-care and Opti-Free Express resulted in a reduction more than the required mean 3.0 logarithmic reduction against P. aeruginosa. Against the cystic and trophozoite forms of A. castellanii, the log reduction provided by SOLO-care was 1.01 and 1.31 log, respectively. ReNu provided a 0.83 log reduction of the cystic form and a 1.21 log reduction of the trophozoite form. Using Opti-Free Express, the log reduction for both forms was 1.31. SOLO-care led to a 0.61 log reduction of the cystic form of A. polyphaga and a 1.01 log reduction of the trophozoite form. ReNu provided a 0.41 log reduction of the cystic form and a 4.99 log reduction of the trophozoite form. Opti-free Express resulted in a 0.89 log reduction of the cystic form and a 3.11 log reduction of the trophozoite form.

Multipurpose contact lens solutions using similar regimens can show different disinfection abilities.