title: Epithelial healing and clinical outcomes in excimer laser photorefractive surgery following three epithelial removal techniques: mechanical, alcohol, and excimer laser.
abstract: OBJECTIVE
  To evaluate epithelial healing, postoperative pain, and visual and refractive outcomes after photorefractive keratectomy (PRK) using three epithelial removal techniques.
  
  
  METHODS
  Prospective, nonrandomized, comparative trial.
  
  
  METHODS
  
  
  
  METHODS
  Department of Ophthalmology, Yonsei University College of Medicine and Balgensesang Ophthalmology Clinic, Seoul, Korea.
  
  
  METHODS
  For the PRK procedure, the corneal epithelium was removed in one of three ways: mechanically (conventional PRK [PRK]) in 88 eyes of 44 patients; using excimer laser (transepithelial PRK [tPRK]) in 106 eyes of 53 patients; or using 20% diluted alcohol, laser-assisted subepithelial keratomileusis (LASEK) in 106 eyes of 53 patients.
  
  
  METHODS
  Epithelial healing, postoperative pain, uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), and remaining refractive error.
  
  
  RESULTS
  The mean postoperative pain scores were 4.84 +/- 1.45 for PRK, 4.71 +/- 1.62 for tPRK, and 4.63 +/- 1.52 for LASEK (P = .125). The mean epithelial healing rates were 12.3 +/- 4.6 for PRK, 15.2 +/- 4.9 for tPRK, and 18.1 +/- 5.2 mm2/day for LASEK (P < .001). The postoperative 6-month remaining mean spherical equivalents (diopters) were -0.46 +/- 1.01 for PRK, 0.18 +/- 0.91 for tPRK, and -0.82 +/- 1.18 for LASEK (P = .01). The LASEK group showed less favorable UCVA than other groups. There was no significant difference in BSCVA between the groups.
  
  
  CONCLUSIONS
  Postoperative pain, subepithelial opacity and BSCVA were similar regardless of the epithelial removal procedure. A faster epithelial healing rate did not result in better visual or refractive outcomes. Using the same nomogram, tPRK resulted in a slight overcorrection, and LASEK resulted in a slight undercorrection.
authors.affiliation: Institute of Vision Research, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Hyung Keun
authors.initials: HK
authors.lastname: Lee
authors.forename: Kyung Sub
authors.initials: KS
authors.lastname: Lee
authors.forename: Jin Kook
authors.initials: JK
authors.lastname: Kim
authors.forename: Hyeon Chang
authors.initials: HC
authors.lastname: Kim
authors.forename: Kyung Ryul
authors.initials: KR
authors.lastname: Seo
authors.forename: Eung Kweon
authors.initials: EK
authors.lastname: Kim
mesh_terms: D000328:Adult; D003318:Corneal Opacity / Q000503:physiopathology; D003646:Debridement / Q000379:methods*; D004311:Double-Blind Method; D019573:Epithelium, Corneal / Q000502:physiology*; D005260:Female; D006801:Humans; D049008:Keratectomy, Subepithelial, Laser-Assisted / Q000379:methods*; D054018:Lasers, Excimer; D008297:Male; D009216:Myopia / Q000601:surgery; D010147:Pain Measurement; D010149:Postoperative Pain / Q000503:physiopathology; D018903:Photorefractive Keratectomy / Q000379:methods*; D011446:Prospective Studies; D012029:Refraction, Ocular / Q000502:physiology; D012030:Refractive Errors / Q000503:physiopathology; D016896:Treatment Outcome; D014792:Visual Acuity / Q000502:physiology; D014945:Wound Healing