title: Contact lens-induced corneal peripheral swelling differences with extended wear.
abstract: OBJECTIVE
  To compare central and peripheral corneal swelling with high-Dk (lotrafilcon A) and low-Dk (etafilcon A) contact lenses (CLs) during extended wear (EW).
  
  
  METHODS
  Corneal thickness was measured in 5 corneal locations (central, superior, inferior, nasal, and temporal) with Orbscan II pachymetry 1 week before the wearing of CLs and after 1 week of EW. High-Dk (lotrafilcon A) and low-Dk (etafilcon A) soft CLs were randomly fitted for EW in the right and left eyes of 20 subjects with normal ocular health. Orbscan was also performed before CL removal after 3 and 7 days of EW.
  
  
  RESULTS
  Lotrafilcon A induced a lower percentage of corneal swelling in all 5 corneal locations than etafilcon A (P < 0.05, paired t test). Lotrafilcon A swelling percentages were as follows: central (1.67% +/- 2.22%), superior (2.04% +/- 3.25%), inferior (1.38% +/- 1.74%), nasal (1.50% +/- 2.00%), and temporal (1.27% +/- 1.47%). Etafilcon A swelling percentages were as follows: central (4.98% +/- 3.07%), superior (6.62% +/- 8.39%), inferior (5.24% +/- 5.54%), nasal (3.41% +/- 3.14%), and temporal (4.46% +/- 3.32%). Differences between the central and peripheral corneal swelling during EW of both types of lenses were not significant (P > 0.05, repeated-measures analysis of variance).
  
  
  CONCLUSIONS
  Central and peripheral corneal thicknesses increase more with etafilcon A than with lotrafilcon A during EW, as measured by Orbscan pachymetry.
authors.affiliation: Department of Physics TAO, School of Optometry, University of Valladolid, Valladolid, Spain. raul@ioba.med.uva.es
authors.forename: Raul
authors.initials: R
authors.lastname: Martin
authors.forename: Victoria
authors.initials: V
authors.lastname: de Juan
authors.forename: Guadalupe
authors.initials: G
authors.lastname: Rodriguez
authors.forename: Soraya
authors.initials: S
authors.lastname: Fonseca
authors.forename: Sofia
authors.initials: S
authors.lastname: Martin
mesh_terms: D000328:Adult; D003262:Contact Lenses, Extended-Wear / Q000009:adverse effects*; D003263:Contact Lenses, Hydrophilic / Q000009:adverse effects*; D015715:Corneal Edema / Q000175:diagnosis / Q000209:etiology*; D003941:Diagnostic Techniques, Ophthalmological; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D020100:Hydrogels / Q000009:adverse effects*; D008297:Male; D008689:Methacrylates / Q000009:adverse effects*; D012828:Silicones / Q000009:adverse effects*; D055815:Young Adult; D005466:Fluorocarbons
chemical_list: D020100:Hydrogels; D008689:Methacrylates; D012828:Silicones; C114176:etafilcon; C481129:lotrafilcon A; D005466:Fluorocarbons