Using an In Vitro Model of Lipid Deposition to Assess the Efficiency of Hydrogen Peroxide Solutions to Remove Lipid from Various Contact Lens Materials

Abstract

Purpose: To test the ability of two commercially available hydrogen peroxide disinfection solutions, one containing a surfactant and one without, to remove lipid from various contact lens materials using in vitro radiochemical experiments.

Methods: Etafilcon A, senofilcon A and balafilcon A contact lens materials were incubated in an artificial tear solution (ATS) containing a mixture of lipids, proteins, mucin and either ¹⁴C-cholesterol or ¹⁴C-phosphatidylcholine for 8 h. Following incubation, the lenses were removed, rinsed, and placed for 16 h in either a surfactant-containing peroxide solution (ClearCare^®), a peroxide solution devoid of a surfactant (AOSept^®) or stored without solution (control). This process was repeated every day for 1 week. The lenses were extracted with a previously optimized extraction protocol, evaporated, re-suspended, fluor added and counted for their radioactive signals. Masses of lipids deposited were calculated based on standard calibration curves, the disinfection solutions were compared and repeated measures ANOVA and post hoc statistical analysis was completed using Statistica 9.

Results: The results of this experiment found that daily disinfection with hydrogen peroxide solutions reduced the amount of cholesterol and phosphatidylcholine deposited on the three contact lens materials examined, however in many cases the reduction in deposition was less than 15% when compared to the control. Disinfection with the solution containing the surfactant (ClearCare), resulted in the least deposited cholesterol and phosphatidylcholine for all materials, however not all of the comparisons were statistically significant.

Conclusions: Overall, ClearCare hydrogen peroxide disinfection solution containing Pluronic 17R4 removed the most lipid from lenses when compared to the non-surfactant containing AOSept or the control, for both lipids and all lens materials. However, the differences found were quite small at times and whether these differences are clinically significant are yet to be determined.

KEYWORDS::

• Contact lens
• Lipid
• Disinfection solutions
• Hydrogen peroxide

Declaration of interest: This study was sponsored by Alcon Research Ltd. One of the authors (Lyndon Jones) has received funding over the past 3 years from the following companies, who either are directly involved in products used in this manuscript or are involved in the manufacture of competing products—Alcon, AMO, B&L, CIBA Vision, CooperVision, and Johnson & Johnson.