title: Failure of mechanical epithelial removal to reverse persistent hyperopia after photorefractive keratectomy.
abstract: BACKGROUND
  Residual hyperopic overcorrection after photorefractive keratectomy (PRK) using early algorithms is a rare but serious complication. Anecdotal evidence suggests that epithelial removal can stimulate epithelial hyperplasia, thereby reducing overcorrection. The aim of this study was to determine if epithelial removal effectively reduced hyperopia after PRK for myopia and, concurrently, to correlate the healing response with the refractive outcome.
  
  
  METHODS
  Enrolled were seven eyes of seven patients (mean age, 44 +/- 13 years) who had undergone PRK with a mean manifest refractive error of +2.21 +/- 0.74 diopters (D). All had undergone PRK an average of 24 +/- 9 months previously. Epithelial removal was performed over the excimer-treated zone with a surgical blade. Subjective refraction, epithelial thickness, corneal topography, and subepithelial haze were measured up to 1 year postoperatively.
  
  
  RESULTS
  Reduction in hyperopia between the baseline and 1-year visit was not statistically significant (mean difference, 0.55 D reduction; p = .102). That epithelial removal did not stimulate a wound-healing response is further supported by the absence of change in epithelial thickness over the first month and the small amounts of subepithelial haze. Central corneal power was reduced by a mean of 0.64 D after 1 month (p < .05).
  
  
  CONCLUSIONS
  Epithelial removal alone did not reduce the hyperopic overcorrection present after PRK, nor did it stimulate epithelial hyperplasia in the majority of these eyes. However, a trend toward improvement was noted with time was noted.
authors.affiliation: Cooperative Research Centre for Eye Research and Technology, University of New South Wales, Sydney, Australia.
authors.forename: C A
authors.initials: CA
authors.lastname: Gauthier
authors.forename: P
authors.initials: P
authors.lastname: Fagerholm
authors.forename: D
authors.initials: D
authors.lastname: Epstein
authors.forename: B A
authors.initials: BA
authors.lastname: Holden
authors.forename: B
authors.initials: B
authors.lastname: Tengroth
authors.forename: H
authors.initials: H
authors.lastname: Hamberg-Nystrom
mesh_terms: D000328:Adult; D003315:Cornea / Q000473:pathology / Q000601:surgery*; D004848:Epithelium / Q000473:pathology / Q000601:surgery; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006956:Hyperopia / Q000209:etiology* / Q000503:physiopathology / Q000601:surgery; D006965:Hyperplasia / Q000473:pathology / Q000601:surgery; D007091:Image Processing, Computer-Assisted; D054018:Lasers, Excimer; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000601:surgery*; D010784:Photomicrography; D018903:Photorefractive Keratectomy / Q000009:adverse effects*; D014792:Visual Acuity