title: Effect of softperm lens wear on corneal thickness and topography: a comparison between keratoconic and normal corneae.
abstract: OBJECTIVE
  Complications related to contact lens-induced anoxia in the keratoconic eye are well documented, but the underlying mechanisms are poorly understood. This study compared topographical changes in corneal thickness and anterior corneal radius following SoftPerm (Ciba Vision, Atlanta, GA) (rigid-and-soft combination) lens wear in a group of keratoconic and normal individuals.
  
  
  METHODS
  Video keratoscopic (VKS) (EyeSys, Houston, TX) and ultrasonographic pachometry measurements were taken at nine ocular locations, at central, mid-peripheral, and peripheral corneal areas of keratoconic and normal subjects. Subjects were subsequently fitted with SoftPerm lenses and further measurements of corneal topography and thickness were noted after 1 day, 2 weeks, and 1 month of daily wear.
  
  
  RESULTS
  Corneal thickness increased significantly in normal and keratoconic eyes following SoftPerm lens wear. Radius values obtained from the VKS measurements indicated that a significant and progressive degree of corneal flattening occurred for the keratoconic subjects at the 1-day, 2-week, and 1-month intervals, in contrast to the normal group, whose corneal radii remained unchanged.
  
  
  CONCLUSIONS
  Corneal swelling occurs in both normal and keratoconic corneas following SoftPerm lens wear. Differences in the apparent central edema response within the keratoconic group may relate to the ease with which these corneas may be molded by a rigid contact lens.
authors.affiliation: Department of Optometry & Vision Science, University of Auckland, New Zealand.
authors.forename: Helen
authors.initials: H
authors.lastname: Owens
authors.forename: Grant
authors.initials: G
authors.lastname: Watters
authors.forename: Greg
authors.initials: G
authors.lastname: Gamble
mesh_terms: D000328:Adult; D003262:Contact Lenses, Extended-Wear / Q000009:adverse effects*; D003315:Cornea / Q000473:pathology*; D015715:Corneal Edema / Q000209:etiology / Q000473:pathology; D019781:Corneal Topography; D006801:Humans; D007640:Keratoconus / Q000473:pathology*; D012016:Reference Values; D013997:Time Factors