Abstract
Purpose:
To determine the efficacy of saline and multi-purpose solutions (MPS) on the removal of cholesterol deposits from silicone hydrogel (SH) contact lens materials using an in vitro model.
Methods:
Six SH lens materials: senofilcon A (Acuvue Oasys), comfilcon A (Biofinity), balafilcon A (Pure Vision2), lotrafilcon A (Air Optix® Night and Day Aqua), lotrafilcon B (Air Optix® Aqua) and lotrafilcon B toric (Air Optix® for Astigmatism) were removed from the blister pack (n=4 for each lens type), incubated for 7 days at 37°C in an artificial tear solution (ATS) containing 14-C radiolabeled cholesterol. Thereafter, lenses were cleaned with an unpreserved saline solution (Sensitive Eyes) or one of five MPS (Opti-Free® PureMoist, renu fresh, RevitaLens, Biotrue, SoloCare Aqua) using a rub and rinse technique, according to the manufacturer recommendations, and stored in the MPS for a minimum of six hours. Lenses were then extracted with 2:1 chloroform:methanol, analyzed in a beta counter and µg/lens of cholesterol was determined.
Results:
Balafilcon A and senofilcon A showed the highest amounts of accumulated cholesterol (0.93±0.02µg/lens, 0.95±0.01µg/lens respectively), while lotrafilcon A and lotrafilcon B deposited the lowest amounts (0.37±0.03; 0.47±0.12). OptiFree PureMoist removed more cholesterol than the other solutions for all lens materials; however, the amount of cholesterol cleaned was statistically significant for balafilcon A and senofilcon A lens materials (p=0.006 and p=0.042). Sensitive Eyes and the other MPS evaluated showed no significant effect on lipid removal (p>0.05).
Conclusions:
Lipid-removal efficacy varies depending on the combination of lens material and solution. Only one MPS showed a significant reduction of lipids for any of the lenses tested. It will be valuable to conduct further work to determine the efficacy of MPS in removing lipid deposits on worn lenses and how these deposits may impact subjective comfort.
Keywords: 477 contact lens