title: Photovaporization rate and profile of an erbium-chromium:YAG laser in the fundamental mode.
abstract: OBJECTIVE
  To evaluate the ablation characteristics of an experimental erbium:YAG (Er:YAG) laser and assess whether it delivers sufficient output for performing photorefractive keratectomy.
  
  
  METHODS
  Department of Ophthalmology, Virchow-Clinics, Humboldt University, Berlin, Germany.
  
  
  METHODS
  An experimental Er:YAG laser, the erbium-chromium:YAG, running in fundamental mode was used to evaluate the energy profile. Measurements obtained using a joulemeter were compared to the ablation profiles of cadaver pig eyes. The pig eyes were treated with different fluences (mean 0.8 to 2.9 J/cm2) and, after histological preparation, were examined using light and scanning electron microscopy.
  
  
  RESULTS
  Measurements with the joulemeter and in the cadaver pig eyes showed a Gaussian-curved profile of energy (ablation). In the current setting, the diameter of ablation was 3.5 mm. Histological examination showed a homogeneous profile of ablation with minor thermal damage.
  
  
  CONCLUSIONS
  The Er:YAG laser running in the fundamental mode allows homogeneous ablation of corneal tissue. The Er:YAG laser is easier to handle technically than the excimer laser and has none of the potential risks of ultraviolet light.
authors.affiliation: Department of Ophthalmology, Virchow-Clinics, Humboldt University, Berlin, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Holschbach
authors.forename: C
authors.initials: C
authors.lastname: Wirbelauer
authors.forename: T
authors.initials: T
authors.lastname: Krämer
authors.forename: J
authors.initials: J
authors.lastname: Wollensak
mesh_terms: D000818:Animals; D003315:Cornea / Q000601:surgery* / Q000648:ultrastructure; D053685:Laser Therapy / Q000295:instrumentation*; D054018:Lasers, Excimer; D009216:Myopia / Q000473:pathology / Q000601:surgery; D018903:Photorefractive Keratectomy / Q000379:methods; D013552:Swine; D014835:Volatilization