title: The effect of nonpreserved care solutions on 12 months of daily and extended silicone hydrogel contact lens wear.
abstract: OBJECTIVE
  To determine the effects of nonpreserved care solutions on human corneal epithelium in long-term daily wear (DW) compared with overnight (extended) wear (EW) of hyper-oxygen-permeable silicone hydrogel contact lenses.
  
  
  METHODS
  This was a prospective, randomized, double-masked, single-center, parallel treatment group clinical trial (NCT 00344643). One hundred twenty-one patients completed the 13 month study: (1) Lotrafilcon A (30 night EW, n = 29; DW, n = 32); (2) Galyfilcon A (DW, n = 20); and (3) Lotrafilcon B (6 night EW, n = 20; DW, n = 21). Irrigation chamber collection of corneal surface cells (OD) and confocal microscopy (OS) were performed at baseline, 1 week; and 1, 3, 6, 9, and 12 months of EW. The main outcome measures were: (1) Pseudomonas aeruginosa (PA) binding to exfoliated corneal surface cells; (2) central epithelial thickness (CET); and (3) epithelial surface cell exfoliation rate (desquamation).
  
  
  RESULTS
  DW had no significant effect on CET; there was a decrease in CET with EW that recovered (adapted) over 1 year (Lotrafilcon B, P < 0.05). All lens wear (DW, EW) decreased desquamation with adaptive effects over 1 year (P < 0.001). There was no significant difference in PA binding between lenses or modality of wear.
  
  
  CONCLUSIONS
  PA binding to corneal epithelial cells is a prerequisite for infection, and no binding indicates no lens-enhanced risk of infection. In contrast to prior studies of preserved lens-care products, the absence of a change in the PA binding data results predict that the risk for PA CTL-keratitis should be similar for daily and extended silicone hydrogel lens wear over 1 year when preservative-free care solutions are used.
authors.affiliation: Department of Ophthalmology, The University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA. danielle.robertson@utsouthwestern.edu
authors.forename: Danielle M
authors.initials: DM
authors.lastname: Robertson
authors.forename: W Matthew
authors.initials: WM
authors.lastname: Petroll
authors.forename: H Dwight
authors.initials: HD
authors.lastname: Cavanagh
mesh_terms: D000328:Adult; D001422:Bacterial Adhesion / Q000502:physiology*; D018639:Contact Lens Solutions / Q000494:pharmacology*; D003262:Contact Lenses, Extended-Wear; D003263:Contact Lenses, Hydrophilic; D004311:Double-Blind Method; D019573:Epithelium, Corneal / Q000187:drug effects* / Q000378:metabolism; D005260:Female; D006801:Humans; D020100:Hydrogels; D008297:Male; D018613:Microscopy, Confocal; D011310:Preservatives, Pharmaceutical / Q000494:pharmacology; D011446:Prospective Studies; D011550:Pseudomonas aeruginosa / Q000502:physiology*; D012828:Silicones; D005466:Fluorocarbons
chemical_list: D018639:Contact Lens Solutions; D020100:Hydrogels; D011310:Preservatives, Pharmaceutical; D012828:Silicones; C481129:lotrafilcon A; D005466:Fluorocarbons; C524582:lotrafilcon B