title: [Impact of an Er:YAG laser beam control on cut quality of non-mechanical corneal trepanation for penetrating keratoplasty].
abstract: BACKGROUND
  Results of non-mechanical corneal trepanation using the excimer laser enhance the morphological and functional results for penetrating keratoplasty. Searching for alternative laser sources we assessed the impact of an automatic laser beam control for the Er:YAG solid-state laser on the cut performance and thermal damage zone in non-mechanical corneal trepanation.
  
  
  METHODS
  We compared the cut quality of A) a manually guided laser beam, B) a semiautomatically guided laser beam and C) a fully PC-controlled laser beam positioning system (q-switched, repetition rate 5 Hz, pulse energy 65 mJ, spot size 0.7 mm) along slit aperture masks on 28 rabbit eyes using macroscopic images and histological sections (PAS staining).
  
  
  RESULTS
  The manually guided laser beam control (A) induced the broadest thermal damage zone in the corneal stroma (19.3+/-8.7 microm) compared to the semi-automatic mode (B) (8.8+/-3.0 microm, p=0.03) and the PC-controlled laser beam control (C) (7.0+/-3.0 microm, p=0.016).
  
  
  CONCLUSIONS
  The fully automatic PC-controlled laser beam positioning system for the Er:YAG solid-state laser with a small spot size and fixed low repetition rate allows a precise laser beam guidance and a significant enhancement of the cut performance compared to a manual laser beam control via micromanipulator in experimental nonmechanical corneal trepanation.
authors.affiliation: Augenklinik mit Poliklinik der Universität Erlangen-Nuremberg, Erlangen. anja.viestenz@augen.imed.uni-erlangen.de
authors.forename: Anja
authors.initials: A
authors.lastname: Viestenz
authors.forename: B
authors.initials: B
authors.lastname: Seitz
authors.forename: M
authors.initials: M
authors.lastname: Küchle
authors.forename: A
authors.initials: A
authors.lastname: Langenbucher
authors.forename: Arne
authors.initials: A
authors.lastname: Viestenz
authors.forename: C
authors.initials: C
authors.lastname: Hofmann-Rummelt
authors.forename: G O H
authors.initials: GO
authors.lastname: Naumann
mesh_terms: D000818:Animals; D003315:Cornea / Q000473:pathology; D065306:Corneal Injuries; D004867:Equipment Design; D015948:Keratoplasty, Penetrating / Q000009:adverse effects / Q000295:instrumentation*; D053685:Laser Therapy / Q000009:adverse effects / Q000295:instrumentation*; D008838:Microcomputers; D011817:Rabbits; D025321:Surgery, Computer-Assisted / Q000295:instrumentation*; D014945:Wound Healing / Q000502:physiology