Abstract
Purpose::
In light of recent concerns regarding lens care and Fusarium keratitis, the antimicrobial efficacy of currently marketed lens disinfecting solutions in the presence of silicone and conventional hydrogel contact lenses and lens cases was examined. The ISO Stand Alone test of solution efficacy is routinely performed independently of lenses and cases. In-the-case Stand Alone tests with lenses were conducted to assess whether the presence of these materials would impact solution efficacy against F.solani at the specified regimen time. Pooled solution from soak and dry cycles with lens cases and lenses was also examined to assess the impact of repeated material exposure. Additionally, solutions with lenses in the absence of cases were evaluated.
Methods::
Stand Alone tests of alexidine and PHMB lens disinfecting solutions in standard, respective manufacturers’ lens cases with lotrafilcon B or etafilcon A lenses (one lens per well) were performed with F. solani ATCC 36031 according to ISO 14729 methodology.Also, lens cases were cycled for one week (12 hour soak, 12 hour dry) in solutions with lenses. Solution from each cycle was collected, pooled and challenged.Solutions in the absence of lens cases were exposed to one, two, and three contact lenses per type in sterile test tubes and immediately inoculated with F. solani. For all assays, efficacy was assessed at the manufacturer’s specified regimen time with a 24-hour assessment for fungal re-growth.
Results::
At the specified regimen time, the performance of AQuify® Multi-Purpose Solution (MPS) and ReNu MultiPlus® solutions in the presence of lotrafilcon B lenses and respective cases was equivalent to performance in cases without lenses. ReNu Moisture Loc demonstrated a reduced log drop in the presence of both lotrafilcon B and etafilcon A lenses. Performance of pooled solution from lens and case cycling was similar.AQuify MPS exposed to multiple lotrafilcon B lenses demonstrated equivalent performance regardless of the number of lenses. ReNu Moisture Loc efficacy decreased in the presence of both lotrafilcon B and etafilcon A lenses. The number of recovered Fusarium colonies increased as the number of lenses increased.
Conclusions::
In contrast to other solutions evaluated, the ReNu Moisture Loc formulation demonstrated decreased efficacy in the presence of both lotrafilcon B and etafilcon A lenses. The more hydrophilic etafilcon A lens material appears to have greater impact on solution active agents than lotrafilcon B. Solution compatibility with lens and lens case materials warrants investigation during the solution development process.