Abstract
Purpose: :
Contemporary contact lens solutions are very effective against a range of bacteria and fungi. Additionally, it has been shown that lenses and lens cases may uptake the active ingredient of disinfecting solutions to a limited degree. However, despite the use of a lens care disinfection regimen and residual active uptake, lens and case contamination still occurs. Many microorganisms possess an inherent propensity to attach to surfaces and may exhibit increased tolerance to disinfection upon attachment. Pseudomonas aeruginosa is the most frequent isolate from contact lens–associated corneal ulcers. This study examined the ability of the silver–impregnated PRO–GUARD case, in conjunction with AQuify® MPS, to reduce bacterial adhesion of a Pseudomonas keratitis isolate to a hydrogel lens. Performance of AQuify MPS and the PRO–GUARD case was compared to currently available solution and lens case systems.
Methods: :
Hydrogel lenses were soaked in AQuify MPS in a PRO–GUARD case, in AQuify MPS in a standard case, in OPTI–FREE® EXPRESS® in an OPTI–FREE case, and in ReNu® with MoistureLocTM in a ReNu case for the recommended disinfecting period. Lenses were then removed, rinsed briefly in phosphate buffered saline (PBS), returned to their respective PBS–rinsed lens cases, and challenged with 106 saline suspensions of Pseudomonas aeruginosa GSU3 (PAGSU3). After 24 hours adhesion, lenses were rinsed, sonicated, and vortexed to recover adhered bacteria (total CFU/lens).
Results: :
Adhesion of PAGSU3 to AQuify MPS soaked lenses in the PRO–GUARD silver–impregnated case was statistically significantly lower than adhesion to lenses soaked in the ReNu and OPTI–FREE systems. Adhesion to ReNu soaked lenses was greater than adhesion to AQuify MPS and OPTI–FREE soaked lenses in standard cases.
Conclusions: :
Hydrogel lenses soaked in AQuify MPS in the PRO–GUARD silver–impregnated case exhibited a lower degree of primary adhesion than lenses soaked in solution in standard lens cases. The silver case is a promising additional safety–enhancing device for the contact lens care system.
Keywords: contact lens • Pseudomonas • microbial pathogenesis: experimental studies