PURPOSE. PURPOSE: To determine the cytotoxicity potential of six soft contact lens care regimens using several different in vitro tests. METHOD.
METHODS: Neat solutions representative of the solution at the end of the regimen soak time and Group IV soft contact lenses cycled in the solutions served as the test articles in these studies. L929 cells, mouse fibroblasts, were used in the test systems. Solutions were diluted 1:3 with growth medium and tested according to several modifications of the USP Elution Test [ET]. Group IV (vifilcon A) lenses (n=3) were cycled seven times in ~20 mL of solution for each multipurpose solution. The AOSept® Disposable Cup and Disc was used in cycling lenses in AOSept. The lenses were tested according to the USP Direct Contact Test [DCT]. Endpoints evaluated included uptake of Trypan blue, microscopic observation, quantitation by Coulter Counter, and regrowth potential.
RESULTS: Based on these four studies, the following solutions were non-cytotoxic: degraded AOSept, SOLOcare™ MULTI-PURPOSE SOLUTION, and COMPLETE® Comfort PLUS™. Both ReNu products were noncytotoxic according to the DCT test and according to the ET test using the Trypan blue and regrowth potential endpoints; however, quantitation of the cells using the Coulter Counter revealed <50% cells compared to the negative control indicating cell growth inhibition. Alcon OPTI-FREE® Express® with Aldox™ tested cytotoxic in all three Elution Tests. The cells under lenses cycled in OPTI-FREE® Express® with Aldox™ were completely lysed whereas this was not observed for the other products.
CONCLUSIONS. CONCLUSION: The rank order of cytotoxicity based on the USP Elution Test (from least to most cytotoxic) was: degraded AOSept = SOLOcare = COMPLETE Comfort Plus < ReNu MultiPurpose = ReNu MultiPlus << Alcon OPTI-FREE® Express® with Aldox.