1 INTRODUCTION In the mid-1990s, hydrogen peroxide and chlorine- based contact lens cleaning systems had a predominant stance in the market, comprising almost half of all cleaning regimes prescribed. 1, 2 Since then, the two-step hydrogen peroxide, requiring a second neutralization step, and chlorine-based systems have become virtually obsolete and the one-step hydrogen peroxide systems have experienced a drastic drop in use due to the growing popularity of multipurpose solutions. 1, 2 Multipurpose solutions now account for over 85% 1, 2 of the market for contact lens cleaning and disinfection solutions and for many years have been the preference of patients due to their simplicity, ease of use, and speed of use. However, in recent years there have been two worldwide recalls of multipurpose solutions due to microbial keratitis outbreaks 3–5 and there have been reports of an increased prevalence of corneal staining with the use of polyhexamethyl biguanide (PHMB) 6–8 containing multipurpose solutions when combined with certain lenses. Due to these factors, there has been a resurgence of interest in hydrogen peroxide Current Eye Research, 2012; Early Online: 1–10 © 2012 Informa Healthcare USA, Inc. ISSN: 0271-3683 print/1460-2202 online DOI: 10.3109/02713683.2012.682636 Received 13 February 2012; revised 28 March 2012; accepted 01 April 2012 Correspondence: Holly Lorentz, Centre for Contact Lens Research, School of Optometry, University of Waterloo, 200, University Avenue West, Waterloo, Ontario, Canada N2L 3G1. Phone: (519) 888-4567 Extn 31349. Fax: (519) 884–8769. E-mail: hmelchin@uwaterloo.ca ORGINAL ARTICLE Using an In Vitro Model of Lipid Deposition to Assess the Eficiency of Hydrogen Peroxide Solutions to Remove Lipid from Various Contact Lens Materials Holly Lorentz 1 , Miriam Heynen 1 , Helen Tran 1 , and Lyndon Jones 1 1 Centre for Contact Lens Research, School of Optometry, University of Waterloo, Waterloo, Ontario, Canada ABSTRACT Purpose: To test the ability of two commercially available hydrogen peroxide disinfection solutions, one con- taining a surfactant and one without, to remove lipid from various contact lens materials using in vitro radio- chemical experiments. Methods: Etailcon A, senoilcon A and balailcon A contact lens materials were incubated in an artiicial tear solu- tion (ATS) containing a mixture of lipids, proteins, mucin and either 14 C-cholesterol or 14 C-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, luor 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 exam- ined, 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 signiicant. 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 dif- ferences are clinically signiicant are yet to be determined. Keywords: contact lens, lipid, disinfection solutions, hydrogen peroxide Curr Eye Res Downloaded from informahealthcare.com by University of Waterloo on 05/30/12 For personal use only.