title: Effect of excimer laser repetition rate on outcomes after photorefractive keratectomy.
abstract: OBJECTIVE
  To compare the refractive outcomes after photorefractive keratectomy (PRK) for low to moderate myopic corrections using 2 excimer lasers with different repetition rates (200 Hz and 400 Hz).
  
  
  METHODS
  University refractive surgery center.
  
  
  METHODS
  This retrospective study included all consecutive patients who underwent PRK using the 200 Hz or the 400 Hz Allegretto laser platform (WaveLight Laser Technologie AG). Thirty-five patients (70 eyes) and 29 patients (58 eyes) had PRK with the 200 Hz platform and the 400 Hz platform, respectively, using the same surgical technique.
  
  
  RESULTS
  The mean follow-up was 13.22 months +/- 1.16 (SD) (range 11 to 15 months). No intraoperative or early postoperative (eg, late reepithelialization) complications were found in either group. At 1 year, 66 eyes (94.2%) in the 200 Hz group and 56 eyes (96.6%) in the 400 Hz group were within +/-1.00 diopter of the attempted correction. At 3 months, 20 eyes (29%) in the 200 Hz group and 27 eyes (46%) in the 400 Hz group had mild or moderate corneal haze (P = .03). These corneas showed progressive clearing over subsequent months without statistically significant differences in haze formation between the 2 groups. Twelve months after PRK, all corneas in both groups were clear.
  
  
  CONCLUSIONS
  Photorefractive keratectomy for the treatment of low to moderate refractive errors using a 200 Hz or 400 Hz excimer laser gave comparable results.
authors.affiliation: Department of Ophthalmology, Vardinoyannion Eye Institute of Crete, University of Crete, Crete, Greece. kymionis@med.uoc.gr
authors.forename: George D
authors.initials: GD
authors.lastname: Kymionis
authors.forename: Vasilios F
authors.initials: VF
authors.lastname: Diakonis
authors.forename: George
authors.initials: G
authors.lastname: Kounis
authors.forename: Dimitrios I
authors.initials: DI
authors.lastname: Bouzoukis
authors.forename: Eirineos
authors.initials: E
authors.lastname: Gkenos
authors.forename: Harilaos
authors.initials: H
authors.lastname: Ginis
authors.forename: Sonia H
authors.initials: SH
authors.lastname: Yoo
authors.forename: Ioannis G
authors.initials: IG
authors.lastname: Pallikaris
mesh_terms: D000328:Adult; D003315:Cornea / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D054018:Lasers, Excimer / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000601:surgery*; D018903:Photorefractive Keratectomy / Q000009:adverse effects / Q000379:methods*; D012029:Refraction, Ocular / Q000502:physiology; D012086:Reoperation; D012189:Retrospective Studies; D016896:Treatment Outcome; D014792:Visual Acuity / Q000502:physiology