title: Predicting extended wear complications from overnight corneal swelling.
abstract: OBJECTIVE
  To examine the hypothesis that the corneal overnight swelling response (ONSR) is a predictor of ocular complications in contact lens extended wear (EW).
  
  
  METHODS
  The Berkeley Contact Lens Extended Wear Study (CLEWS) was a randomized, concurrently controlled clinical trial in which more than 200 subjects in EW with rigid gas-permeable (RGP) lenses were observed for 1 year. After adapting to EW, subjects were randomized to either medium or high oxygen-permeable (Dk) RGP lenses and underwent clinical assessments, keratometry, and corneal pachometry at 3-month intervals.
  
  
  RESULTS
  The ONSR was directly related to lens Dk (P = 0.01) and exhibited substantial variability across subjects. The probability of remaining free of complications over time was not significantly lower for subjects with a mild ONSR compared with those with greater edema (P = 0.84). The risk of development of keratopathy was not significantly related to the ONSR (relative risk = 1.00).
  
  
  CONCLUSIONS
  The corneal ONSR is not a good predictor of ocular complications in 1 year of RGP EW. Lenses that cause little or no corneal edema are not necessarily safer for overnight wear.
authors.affiliation: School of Optometry, University of California, Berkeley, CA 94720-2020. agraham@spectacle.berkeley.edu
authors.forename: A D
authors.initials: AD
authors.lastname: Graham
authors.forename: R E
authors.initials: RE
authors.lastname: Fusaro
authors.forename: K A
authors.initials: KA
authors.lastname: Polse
authors.forename: M C
authors.initials: MC
authors.lastname: Lin
authors.forename: C J
authors.initials: CJ
authors.lastname: Giasson
mesh_terms: D002940:Circadian Rhythm; D003262:Contact Lenses, Extended-Wear / Q000009:adverse effects*; D003316:Corneal Diseases / Q000209:etiology; D015715:Corneal Edema / Q000209:etiology*; D004867:Equipment Design; D005544:Forecasting; D006801:Humans; D010100:Oxygen; D010539:Permeability; D011446:Prospective Studies; D018570:Risk Assessment; D013997:Time Factors
chemical_list: D010100:Oxygen