title: Daily Wear Contact Lenses Manufactured in Etafilcon A Are Noninferior to Two Silicone Hydrogel Lens Types With Respect to Hypoxic Stress.
abstract: OBJECTIVE
  This study hypothesized that a traditional high-water contact lens of moderate oxygen transmissibility (Dk/t) is noninferior to common silicone hydrogel (SH) lenses worn for daily wear with respect to measures of hypoxic stress.
  
  
  METHODS
  Thirty-six habitual contact lens wearers completed wear of three lens types worn in a randomized order: etafilcon A (ACUVUE 2, control), lotrafilcon B (Air Optix Aqua), and comfilcon A (Biofinity). Central corneal thickness (CT) and limbal hyperemia were measured >2 hr after waking and after 6 to 8 hr of wear on days 1 and 7. Endothelial bleb formation was measured on day 1 of each lens type. Noninferiority of etafilcon A, with respect to the other two lens types, was assumed if the following difference margins of equivalence were met: <1.5% for corneal swelling, <0.5 grade for limbal hyperemia, and <1% area of endothelial blebs. Outcomes were modeled using generalized linear mixed modeling techniques.
  
  
  RESULTS
  All lenses showed reductions in least-square mean estimates of CT on both days: etafilcon A -0.26% at day 1 and -0.31% at day 7; lotrafilcon B -1.11% at day 1 and -1.06% at day 7; comfilcon A -0.63% at day 1 and -0.84% at day 7. The difference in mean swelling between etafilcon A and lotrafilcon B was 0.85% at day 1 (95% confidence interval [0.4%-1.3%]) and 0.75% at day 7 (0.3%-1.2%). The difference in mean swelling between etafilcon A and comfilcon A was 0.37% at day 1 (-0.1% to 0.8%) and 0.53% at day 7 (0.1%-1.0%). For limbal redness, etafilcon A fell within 0.1 grade of lotrafilcon B and 0.18 grade of comfilcon A. For endothelial bleb formation, etafilcon A fell within 0.45% of lotrafilcon B and 0.23% of comfilcon A.
  
  
  CONCLUSIONS
  The etafilcon A control lens resulted in corneal deswelling throughout the day as did the SH lens types. Limbal hyperemia and endothelial bleb formation with all lenses were negligible, and noninferiority assumptions were met between the lens types for all outcomes. Equivalence of etafilcon A with respect to the two SH lenses for three measures of hypoxic stress was demonstrated.
authors: University Hospitals Eye Institute (L.B.S.-F., B.A.B.), University Hospitals Case Medical Center, Cleveland, OH; Departments of Ophthalmology and Visual Sciences (L.B.S.-F., B.A.B.), and Epidemiology and Biostatistics (S.D.), Case Western Reserve University, Cleveland, OH; and Johnson & Johnson Vision Care, Inc. (T.W., N.B.), Jacksonville, FL.
authors: Loretta B
authors: LB
authors: Szczotka-Flynn
authors: Sara
authors: S
authors: Debanne
authors: Beth Ann
authors: BA
authors: Benetz
authors: Tawnya
authors: T
authors: Wilson
authors: Noel
authors: N
authors: Brennan
mesh_terms: D000328:Adult; D001768:Blister / Q000473:pathology; D003263:Contact Lenses, Hydrophilic / Q000009:adverse effects*; D003315:Cornea / Q000503:physiopathology*; D015715:Corneal Edema / Q000209:etiology* / Q000503:physiopathology; D018592:Cross-Over Studies; D004728:Endothelium, Corneal / Q000473:pathology; D005260:Female; D006801:Humans; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D020100:Hydrogels; D000860:Hypoxia / Q000209:etiology*; D016850:Limbus Corneae / Q000473:pathology; D008297:Male; D008689:Methacrylates; D008875:Middle Aged; D011446:Prospective Studies; D012828:Silicones; D013312:Stress, Physiological / Q000502:physiology; D055815:Young Adult
chemical_list: D020100:Hydrogels; D008689:Methacrylates; D012828:Silicones; C540498:comfilcon A; C114176:etafilcon; C524582:lotrafilcon B; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate