title: Photoablation of inner limiting membrane and inner retinal layers using the Erbium:YAG-laser: an in vitro study.
abstract: OBJECTIVE
  To explore the potential of Er:YAG-laser irradiation for precise and tractionless retinal tissue and inner limiting membrane ablation.
  
  
  METHODS
  We used free-running Er:YAG-laser irradiation (lambda = 2.94 microm) transmitted either through a 10 cm long low-OH-quartz fiber or a 2 m long sapphire fiber that produced a more homogenous light distribution at the fiber tip. Retinal ablation in porcine retinal explants was performed under air or perfluorodecaline (PFD). Ablation depth was evaluated by optical coherence tomography (OCT) and from histologic sections.
  
  
  RESULTS
  A radiant exposure of 5.0 J/cm(2) delivered through a low-OH-quartz fiber and PFD caused a complete transsection of the neurosensory retina. Radiant exposures between 3.5 and 2.0 J/cm(2) resulted in marked variations of ablation depth and adjacent thermal damage. By contrast, laser pulses of 4.0 and 3.0 J/cm(2) transmitted through the sapphire fiber produced more homogenous defect patterns and less thermal damage. Close to the ablation threshold, with 1.0-2.0 J/cm(2), ablation was limited to a 10-20 microm thin layer of the neural retina.
  
  
  CONCLUSIONS
  We achieved in vitro ablation of inner retinal layers, but could not produce selective and reproducible ILM removal.
authors.affiliation: University Eye Clinic, Ratzeburger Allee 160, 23538 Luebeck, Germany. hanshoerauf@yahoo.com
authors.forename: Hans
authors.initials: H
authors.lastname: Hoerauf
authors.forename: Alexandra
authors.initials: A
authors.lastname: Brix
authors.forename: Jörg
authors.initials: J
authors.lastname: Winkler
authors.forename: Gerit
authors.initials: G
authors.lastname: Droege
authors.forename: Christian
authors.initials: C
authors.lastname: Winter
authors.forename: Reginald
authors.initials: R
authors.lastname: Birngruber
authors.forename: Horst
authors.initials: H
authors.lastname: Laqua
authors.forename: Alfred
authors.initials: A
authors.lastname: Vogel
mesh_terms: D000818:Animals; D004871:Erbium; D066298:In Vitro Techniques; D053685:Laser Therapy / Q000295:instrumentation*; D013508:Ophthalmologic Surgical Procedures / Q000295:instrumentation*; D012160:Retina / Q000601:surgery*; D013552:Swine
chemical_list: D004871:Erbium