title: The relationship between long-term contact lens wear and corneal thickness.
abstract: OBJECTIVE
  The purpose of this study is to assess the effects of long-term contact lens wear on corneal thickness and to compare differences based on rigid versus soft lens material.
  
  
  METHODS
  This analysis included scanning slit topographic imaging (Orbscan, Bausch & Lomb, Rochester, NY) performed on 124 consecutive patients (248 eyes), who underwent comprehensive evaluations in consideration of refractive surgery by one surgeon.
  
  
  RESULTS
  Sixty-two 62 patients (124 eyes) who had not previously worn contact lenses had a least-squares mean pachymetry of 546.4 microm +/-3.5 SE. Thirty-nine patients (78 eyes) who had previously worn soft contact lenses for an average of 16 years had a least-squares mean pachymetry of 543.2 microm +/-3.8 SE. Twenty-three patients (46 eyes) who had worn rigid contact lenses for an average of 19 years had a least-squares mean pachymetry of 509.4 microm +/-6.9 SE. Mean pachymetry differed significantly between eyes wearing rigid lenses versus no lenses (P<0.0001) and between eyes wearing rigid lenses versus soft lenses (P=0.0002).
  
  
  CONCLUSIONS
  Long-term rigid contact lens wear is associated with a decrease in the average central-corneal thickness (CCT) by an average of 37 microm, in this group of otherwise healthy eyes, compared to no contact lens wear. Long-term soft contact lens wear did not appear to significantly change corneal thickness compared to no contact lens wear. Caution should be exercised when screening patients with a history of long-term rigid contact lens wear for possible excimer-laser photoablative correction.
authors.affiliation: Wilmer Laser Vision Center, The Wilmer Eye Institute, Lutherville, MD 21093, USA.
authors.forename: Elliott H
authors.initials: EH
authors.lastname: Myrowitz
authors.forename: Michelle
authors.initials: M
authors.lastname: Melia
authors.forename: Terrence P
authors.initials: TP
authors.lastname: O'Brien
mesh_terms: D003261:Contact Lenses / Q000009:adverse effects*; D003263:Contact Lenses, Hydrophilic; D003315:Cornea / Q000473:pathology*; D019781:Corneal Topography; D006801:Humans; D013997:Time Factors