ORIGINAL ARTICLE Quantification of Non-Polar Lipid Deposits on Senofilcon A Contact Lenses Miriam Heynen*, Holly Lorentz*, Sruthi Srinivasan † , and Lyndon Jones ‡ ABSTRACT Purpose. To quantify non-polar lipids deposited on senofilcon A silicone hydrogel contact lenses (J&J Acuvue OASYS) when disinfected with a no-rub one-step hydrogen peroxide system (CIBA Vision ClearCare) and a care system preserved with Polyquad & Aldox (Alcon OPTI-FREE RepleniSH). Methods. Thirty existing soft lens wearers symptomatic of dryness were enrolled into a 4-week prospective, randomized, bilateral eye (lens type), cross-over (care regimen), daily wear, double masked study. Subjects were refitted with senofilcon A lenses, which were replaced biweekly. During each period of wear, participants used either the peroxide or preserved system. After each period of wear, lenses were collected and lipid was extracted using 1.5 ml of a 2:1 chloroform:methanol solution for 3 h at 37°C. Lens extracts were analyzed for non-polar lipids [cholesterol oleate (CO), cholesterol, oleic acid (OA), triolein, and OA methyl ester] using normal phase high-performance liquid chromatography. Results. The total lipid (sum of CO and cholesterol) detected was 34  28 g/lens for the peroxide-based system and 22  21 g/lens for the system preserved with Polyquad and Aldox (p = 0.029). Although there was no difference between products for cholesterol (1.4 vs. 1.3 g/lens; p = 0.50), use of a system preserved with Polyquad and Aldox resulted in significantly less deposited CO (33  28 vs. 21  20 g/lens; p = 0.033). Approximately, 95% of the detectable lipid deposited on the material was CO, followed by cholesterol. OA and triolein contributed 1% of the total lipid and no OA methyl ester was found on any of the lenses. Conclusions. A care system preserved with Polyquad and Aldox removed higher amounts of CO from senofilcon A contact lenses used for 2 weeks than a peroxide-based system, in soft lens wearers who were symptomatic of dry eye. (Optom Vis Sci 2011;88:1172–1179) Key Words: silicone hydrogel, contact lens, lens care solutions, lipids, cholesterol, dry eye, deposition H ydrogel contact lenses rapidly sorb components from the tear film, particularly proteins, 1–4 lipids, 3,5– 8 and mu- cins. 2,9 At higher levels of build up, these deposits are associated with altered visual acuity, 10 altered lens wettability, 11 dryness and discomfort, 6,12 increased bacterial adhesion, 13–15 lid- related inflammatory changes, and contact lens-associated papil- lary conjunctivitis. 16,17–19 Lipid deposits on silicone hydrogel (SH) lens materials have attracted significant interest among re- searchers, 9,20 and it is well established that lipid deposition can be an issue with SH contact lens materials. 1,3,9,21 About 45 different lipids have been recognized in human meibum. 22–25 The superficial lipid layer is composed of two dif- ferent lipid phases, with an inner polar-surfactant phase and an outer non-polar phase. 25 The non-polar phase (which contains a large amount of non-polar lipids, including wax esters, cholesterol esters, triglycerides, and hydrocarbons) is larger than the polar phase, hence non-polar lipids are found in greater quantities. 25 There are several factors that influence tear film deposition onto hydrogel contact lenses materials including material composition, water content, 26,27 surface charge, 4,26,28 pore size of the material, 29 hydrophobicity of the material, 30 and tear film characteristics. 6,31 In addition to the aforementioned factors, lens care solutions also play a vital role in the sorption of tear film lipids on to the contact lens surface. Modern-day multipurpose cleaning and disinfecting lens care regimens are complex mixtures of components that include a number of wetting agents, biocides, and surfactants, designed to enhance in- eye wettability and reduce deposition of proteins and lipids on the lens surface. 32 Most commercially available systems are either based on preservatives (such as polyquaternium-1 or Polyhexam- ethylene biguranide) or hydrogen peroxide. Hydrogen peroxide systems tend to be chemically less complex than multipurpose *MSc † BS(Optom), PhD, FAAO ‡ PhD, FCOptom, FAAO Centre for Contact Lens Research, School of Optometry, University of Water- loo, Waterloo, Ontario, Canada. 1040-5488/11/8810-1172/0 VOL. 88, NO. 10, PP. 1172–1179 OPTOMETRY AND VISION SCIENCE Copyright © 2011 American Academy of Optometry Optometry and Vision Science, Vol. 88, No. 10, October 2011