title: Clinical photoablation with a 500-Hz scanning spot excimer laser.
abstract: OBJECTIVE
  The aim of this study was to use a 500-Hz scanning spot laser (Concept500, WaveLight Laser Technologie AG, Erlangen, Germany) to investigate potential side effects that might be associated with the use of a high repetition rate laser platform.
  
  
  METHODS
  Seven eyes were treated using a 500-Hz scanning spot laser for laser in situ keratomileusis (LASIK). The local frequency of the ablation was kept below 40 Hz to avoid local heating of corneal tissue. With the exception of the high repetition rate (500 Hz), all other laser parameters such as fluence, algorithm, ablation profile, and spot diameter were identical to a standard WaveLight Allegretto laser system. Patients were examined at 1 month and 1 year after initial treatment. Preoperative and postoperative examination included manifest sphere and cylinder, uncorrected and best spectacle-corrected visual acuity (BSCVA).
  
  
  RESULTS
  All eyes were treated for myopia or myopic astigmatism. Five eyes received spherocylindrical and two eyes spherical ablation only. No adverse events correlated with the use of a high repetition rate laser system were observed during surgery or at any point during follow-up. All eyes maintained or had improved BSCVA at 12 months after treatment when compared to preoperative values.
  
  
  CONCLUSIONS
  The use of an excimer laser with a maximal repetition rate of 500 Hz and a local repetition rate of less than 40 Hz was free of any specific side effect that might be associated with the use of such a high repetition rate.
authors.affiliation: Institut für Refraktive und Okuloplastische Chirurgie (IROC AG), Zollikerstrasse 164, CH-8008 Zurich, Switzerland. info@iroc.ch
authors.forename: Hans Peter
authors.initials: HP
authors.lastname: Iseli
authors.forename: Michael
authors.initials: M
authors.lastname: Mrochen
authors.forename: Farhad
authors.initials: F
authors.lastname: Hafezi
authors.forename: Theo
authors.initials: T
authors.lastname: Seller
mesh_terms: D000328:Adult; D001251:Astigmatism / Q000601:surgery; D003319:Corneal Stroma / Q000601:surgery*; D006801:Humans; D007431:Intraoperative Complications; D020731:Keratomileusis, Laser In Situ / Q000295:instrumentation / Q000379:methods*; D008297:Male; D009216:Myopia / Q000601:surgery*; D010865:Pilot Projects; D011183:Postoperative Complications; D011446:Prospective Studies; D013524:Surgical Flaps