title: A scanning and rotating slit arF excimer laser delivery system for refractive surgery.
abstract: OBJECTIVE
  This study was designed to investigate the quality of a scanning and rotating slit delivery system of an ArF excimer laser (Nidek EC-5000).
  
  
  METHODS
  The ablation patterns on polymethylmethacrylate (PMMA) wafers were examined by scanning electron microscopy. The influence of inhomogeneities in the beam profile was simulated on a computer and compared with a conventional large-area ablation system. The impairment of the ablation rate by radiation absorption of the ablation plume was measured as a function of the repetition rate and the application of a fixation ring.
  
  
  RESULTS
  The scanning and rotating slit delivery system is tolerant of small-beam non-homogeneities. The ablation rate is sensitive to the dynamics of the ablation plume.
  
  
  CONCLUSIONS
  Although the operating procedure takes less time with a large-area ablation system, a scanning and rotating delivery system has the advantage of reliable and homogeneous removal of corneal tissue.
authors.affiliation: Laser Zentrum Hannover, Germany. hl@lzh.de
authors.forename: H
authors.initials: H
authors.lastname: Lubatschowski
authors.forename: O
authors.initials: O
authors.lastname: Kermani
authors.forename: H
authors.initials: H
authors.lastname: Welling
authors.forename: W
authors.initials: W
authors.lastname: Ertmer
mesh_terms: D003315:Cornea / Q000601:surgery*; D006801:Humans; D054018:Lasers, Excimer; D008855:Microscopy, Electron, Scanning; D008953:Models, Anatomic; D018903:Photorefractive Keratectomy / Q000295:instrumentation*; D019904:Polymethyl Methacrylate; D054140:Refractive Surgical Procedures
chemical_list: D019904:Polymethyl Methacrylate