title: Comparison of LASIK and surface ablation by using propensity score analysis: a multicenter study in Korea.
abstract: OBJECTIVE
  We compared the 3-year outcomes with regard to efficacy, stability, and safety of LASIK and surface ablation performed at multiple centers in Korea.
  
  
  METHODS
  The charts of 5109 eyes that underwent LASIK or surface ablation, including LASEK, epi-LASIK, and photorefractive keratectomy (PRK), at multiple centers between 2002 and 2005 were reviewed. Of these, 577 LASIK-treated eyes and 577 propensity score-matched surface-ablated eyes were included in this cohort study. A standardized case report form (CRF) was completed based on a review of the 3-year follow-up chart. The CRF included the preoperative, surgical, and postoperative data for the refractive error, uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), IOP, corneal thickness, keratometry, corneal topography, Schirmer test, and tear breakup time (TBUT).
  
  
  RESULTS
  The efficacy index calculated after 3 years and the postoperative spherical equivalents measured at 3 months or 3 years did not differ between the LASIK and surface ablation groups. Although myopic regression was observed in the surface ablation group through postoperative years 1 and 2, this difference did not affect the visual acuity significantly. Surface ablation did carry a higher cumulative incidence of corneal haze.
  
  
  CONCLUSIONS
  LASIK and surface ablation produced similar postoperative visual efficacy after corneal healing. The outcome predictability did not differ between the 2 groups, but myopic regression was observed more frequently in the surface ablation group. Corneal haze after surface ablation is much more common than reported previously.
authors.affiliation: Catholic Institute for Visual Science, Seoul St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Kyung-Sun
authors.initials: KS
authors.lastname: Na
authors.forename: So-Hyang
authors.initials: SH
authors.lastname: Chung
authors.forename: Jin Kook
authors.initials: JK
authors.lastname: Kim
authors.forename: Eun Jin
authors.initials: EJ
authors.lastname: Jang
authors.forename: Na Rae
authors.initials: NR
authors.lastname: Lee
authors.forename: Choun-Ki
authors.initials: CK
authors.lastname: Joo
mesh_terms: D000328:Adult; D019573:Epithelium, Corneal / Q000601:surgery; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D020731:Keratomileusis, Laser In Situ / Q000009:adverse effects / Q000379:methods*; D008297:Male; D009216:Myopia / Q000601:surgery*; D018903:Photorefractive Keratectomy / Q000009:adverse effects / Q000379:methods*; D011183:Postoperative Complications / Q000209:etiology*; D011237:Predictive Value of Tests; D056910:Republic of Korea; D012189:Retrospective Studies; D016896:Treatment Outcome; D014792:Visual Acuity; D055815:Young Adult