title: Photorefractive keratectomy and butterfly laser epithelial keratomileusis: a prospective, contralateral study.
abstract: OBJECTIVE
  To evaluate results of two surface excimer laser refractive surgery techniques--photorefractive keratectomy (PRK) and butterfly laser epithelial keratomileusis (butterfly LASEK).
  
  
  METHODS
  A prospective, randomized, double-masked study of 51 patients (102 eyes) who underwent laser refractive surgery. One eye of each patient was randomized to be operated with PRK and the fellow eye with butterfly LASEK. Patients were followed for 1 year.
  
  
  RESULTS
  No significant difference between groups for distance uncorrected visual acuity (UCVA) (P = .559) was noted. At 1 year, 98% (50 eyes) in the PRK group and 96.1% (49 eyes) in the butterfly LASEK group reached UCVA of 20/20. Predictability, efficacy, safety, and stability were not statistically significant between groups. Safety index was 1.0 for PRK and 0.996 for butterfly LASEK. One eye in the butterfly LASEK group lost one line of best-spectacle corrected visual acuity. At 12 months, 94.1% (48 eyes) and 86.3% (44 eyes) in the PRK and butterfly LASEK groups (P = .188), respectively, had a spherical equivalent refraction of +/- 0.50 diopters. Slight haze was observed in both groups. A statistical difference in haze between the groups was observed only in the first postoperative month, with higher intensity in the butterfly LASEK group (0.18 +/- 0.39) compared to the PRK group (0.08+/- 0.21) (P = .04).
  
  
  CONCLUSIONS
  Butterfly LASEK had similar predictability, efficacy, safety, stability, and haze incidence to PRK for the treatment of low to moderate myopia. However, on the second postoperative day, PRK showed better UCVA than butterfly LASEK.
authors.affiliation: Sadalla Amin Ghanem Eye Hospital, Joinville/Santa Catarina, Brazil. vcghanem@hotmail.com
authors.forename: Vinícius Coral
authors.initials: VC
authors.lastname: Ghanem
authors.forename: Newton
authors.initials: N
authors.lastname: Kara-José
authors.forename: Ramon Coral
authors.initials: RC
authors.lastname: Ghanem
authors.forename: Samuel Angelo
authors.initials: SA
authors.lastname: Coral
mesh_terms: D000328:Adult; D003319:Corneal Stroma / Q000503:physiopathology / Q000601:surgery*; D004311:Double-Blind Method; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology; D049008:Keratectomy, Subepithelial, Laser-Assisted / Q000379:methods*; D054018:Lasers, Excimer; D008297:Male; D009216:Myopia / Q000503:physiopathology / Q000601:surgery*; D018903:Photorefractive Keratectomy / Q000379:methods*; D011446:Prospective Studies; D012029:Refraction, Ocular / Q000502:physiology; D013524:Surgical Flaps; D016896:Treatment Outcome; D014792:Visual Acuity / Q000502:physiology