title: Corneal topographic alterations in normal contact lens wearers.
abstract: OBJECTIVE
  The purpose of this study is to investigate the corneal topography of visually normal asymptomatic eyes that wore rigid and soft contact lenses compared with visually normal eyes that had never worn contact lenses.
  
  
  METHODS
  Thirty-seven normal corneas and 74 corneas in asymptomatic eyes that wore rigid (12 polymethylmethacrylate and 23 gas-permeable) and soft (26 daily-wear and 13 extended-wear) contact lenses for refractive correction underwent slit-lamp examination, keratometry, computer-assisted topographic analysis, refraction, and rigid contact lens over-refraction.
  
  
  RESULTS
  Topographic abnormalities tended to be more common and more severe in corneas that wore rigid contact lenses, but significant changes were noted in some eyes that wore daily-wear or extended-wear soft contact lenses. A number of eyes in the rigid polymethylmethacrylate (9 of 12) and rigid gas-permeable (6 of 23) contact lens groups had a correlation between the most frequent resting position of the contact lens and the corneal topography, with relative flattening of the corneal contour beneath a decentered lens. A total of 10 eyes in the rigid contact lens groups had a 1-line decrease in best spectacle-corrected visual acuity attributable to contact lens-induced topographic abnormalities.
  
  
  CONCLUSIONS
  Corneal topographic alterations are common in asymptomatic contact lens wearers and are frequently detectable only with computer-assisted topographic analysis. It is important that topographic abnormalities be excluded in contact lens wearing eyes before refractive surgical procedures.
authors.affiliation: Department of Opthalmology, University of Texas Southwestern Medical Center, Dallas 75235-9057.
authors.forename: J
authors.initials: J
authors.lastname: Ruiz-Montenegro
authors.forename: C H
authors.initials: CH
authors.lastname: Mafra
authors.forename: S E
authors.initials: SE
authors.lastname: Wilson
authors.forename: J M
authors.initials: JM
authors.lastname: Jumper
authors.forename: S D
authors.initials: SD
authors.lastname: Klyce
authors.forename: E N
authors.initials: EN
authors.lastname: Mendelson
mesh_terms: D003261:Contact Lenses / Q000009:adverse effects*; D003315:Cornea / Q000033:anatomy & histology / Q000473:pathology*; D003316:Corneal Diseases / Q000209:etiology / Q000473:pathology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D020366:Methylmethacrylate; D008768:Methylmethacrylates; D014792:Visual Acuity
chemical_list: D008768:Methylmethacrylates; D020366:Methylmethacrylate