Epithelial healing and clinical outcomes in excimer laser photorefractive surgery following three epithelial removal techniques: mechanical, alcohol, and excimer laser

Am J Ophthalmol. 2005 Jan;139(1):56-63. doi: 10.1016/j.ajo.2004.08.049.


Purpose: To evaluate epithelial healing, postoperative pain, and visual and refractive outcomes after photorefractive keratectomy (PRK) using three epithelial removal techniques.

Design: Prospective, nonrandomized, comparative trial.

Setting: Department of Ophthalmology, Yonsei University College of Medicine and Balgensesang Ophthalmology Clinic, Seoul, Korea.

Interventions: 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.

Main outcome measures: 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.

Publication types

  • Clinical Trial
  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Corneal Opacity / physiopathology
  • Debridement / methods*
  • Double-Blind Method
  • Epithelium, Corneal / physiology*
  • Female
  • Humans
  • Keratectomy, Subepithelial, Laser-Assisted / methods*
  • Lasers, Excimer
  • Male
  • Myopia / surgery
  • Pain Measurement
  • Pain, Postoperative / physiopathology
  • Photorefractive Keratectomy / methods*
  • Prospective Studies
  • Refraction, Ocular / physiology
  • Refractive Errors / physiopathology
  • Treatment Outcome
  • Visual Acuity / physiology
  • Wound Healing*