title: Quantification of non-polar lipid deposits on senofilcon a contact lenses.
abstract: OBJECTIVE
  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 μg/lens for the peroxide-based system and 22 ± 21 μg/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 μg/lens; p = 0.50), use of a system preserved with Polyquad and Aldox resulted in significantly less deposited CO (33 ± 28 vs. 21 ± 20 μg/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.
authors.affiliation: Centre for Contact Lens Research, School of Optometry, University of Waterloo, Waterloo, Ontario, Canada.
authors.forename: Miriam
authors.initials: M
authors.lastname: Heynen
authors.forename: Holly
authors.initials: H
authors.lastname: Lorentz
authors.forename: Sruthi
authors.initials: S
authors.lastname: Srinivasan
authors.forename: Lyndon
authors.initials: L
authors.lastname: Jones
mesh_terms: D000293:Adolescent; D000328:Adult; D002851:Chromatography, High Pressure Liquid; D003262:Contact Lenses, Extended-Wear; D018592:Cross-Over Studies; D004311:Double-Blind Method; D015352:Dry Eye Syndromes / Q000378:metabolism* / Q000517:prevention & control; D004866:Equipment Contamination; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D020100:Hydrogels / Q000737:chemistry*; D008055:Lipids / Q000032:analysis*; D008297:Male; D011446:Prospective Studies; D012828:Silicones / Q000737:chemistry*; D013499:Surface Properties; D055815:Young Adult
chemical_list: D020100:Hydrogels; D008055:Lipids; D012828:Silicones; C523196:senofilcon A