title: [Perspectives of laser-assisted keratoplasty: current overview and first preliminary results with the picosecond infrared laser (λ = 3 µm)].
abstract: BACKGROUND
  This article provides a review of the current state of laser-assisted keratoplasty and describes a first proof of concept study to test the feasibility of a new mid-infrared (MIR) picosecond laser to perform applanation-free corneal trephination.
  
  
  METHODS
  The procedure is based on a specially adapted laser system (PIRL-HP2-1064 OPA-3000, Attodyne, Canada) which works with a wavelength of 3,000 ± 90 nm, a pulse duration of 300 ps and a repetition rate of 1 kHz. The picosecond infrared laser (PIRL) beam is delivered to the sample by a custom-made optics system with an implemented scanning mechanism. Corneal specimens were mounted on an artificial anterior chamber and subsequent trephination was performed with the PIRL under stable intraocular pressure conditions.
  
  
  RESULTS
  A defined corneal ablation pattern, e.g. circular, linear, rectangular or disc-shaped, can be selected and its specific dimensions are defined by the user. Circular and linear ablation patterns were employed for the incisions in this study. Linear and circular penetrating PIRL incisions were examined by macroscopic inspection, histology, confocal microscopy and environmental scanning electron microscopy (ESEM) for characterization of the incisional quality. Using PIRL reproducible and stable incisions could be made in human and porcine corneal samples with minimal damage to the surrounding tissue.
  
  
  CONCLUSIONS
  The PIRL laser radiation in the mid-infrared spectrum with a wavelength of 3 µm is exactly tuned to one of the dominant vibrational excitation bands of the water molecule, serves as an effective tool for applanation-free corneal incision and might broaden the armamentarium of corneal transplant surgery.
authors.affiliation: Klinik und Poliklinik für Augenheilkunde, Universitätsklinikum Eppendorf (UKE), Martinistr. 52, 20246, Hamburg, Deutschland, slinke@uke.de.
authors.forename: S J
authors.initials: SJ
authors.lastname: Linke
authors.forename: L
authors.initials: L
authors.lastname: Ren
authors.forename: A
authors.initials: A
authors.lastname: Frings
authors.forename: J
authors.initials: J
authors.lastname: Steinberg
authors.forename: W
authors.initials: W
authors.lastname: Wöllmer
authors.forename: T
authors.initials: T
authors.lastname: Katz
authors.forename: R
authors.initials: R
authors.lastname: Reimer
authors.forename: N O
authors.initials: NO
authors.lastname: Hansen
authors.forename: N
authors.initials: N
authors.lastname: Jowett
authors.forename: G
authors.initials: G
authors.lastname: Richard
authors.forename: R J
authors.initials: RJ
authors.lastname: Dwayne Miller
mesh_terms: D003316:Corneal Diseases / Q000601:surgery*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006801:Humans; D007259:Infrared Rays / Q000627:therapeutic use*; D015948:Keratoplasty, Penetrating / Q000295:instrumentation* / Q000379:methods; D007834:Lasers; D010865:Pilot Projects; D016896:Treatment Outcome