title: Evaluation of a 345 nm Femtosecond Laser for Corneal Surgery with Respect to Intraocular Radiation Hazard.
abstract: OBJECTIVE
  We report our findings from a preclinical safety study designed to assess potential side effects of corneal ultraviolet femtosecond laser treatment on lens and retina.
  
  
  METHODS
  Refractive lenticules (-5 dpt) with a diameter of 6 mm were created in the right cornea of eight Dutch Belted rabbits. Radiant exposure was 0.5 J/cm² in two animals and 18 J/cm² in six animals. The presence of lens opacities was assessed prior to and up to six months following laser application using Scheimpflug images (Pentacam, Oculus) and backscatter analysis (Opacity Lensmeter 702, Interzeag). Ganzfeld flash and flicker electroretinogram (ERG) recordings were obtained from both eyes prior to and up to six weeks following laser application. At the study endpoint, retinas were examined by light microscopy.
  
  
  RESULTS
  Independent of energy dose applied, no cataract formation could be observed clinically or with either of the two objective methods used. No changes in ERG recordings over time and no difference between treated and untreated eye were detected. Histologically, retinal morphology was preserved and retinal pigment epithelium as well as photoreceptor inner and outer segments appeared undamaged. Quantitative digital image analysis did not reveal cell loss in inner or outer nuclear layers.
  
  
  CONCLUSIONS
  Our analysis confirms theoretical considerations suggesting that ultraviolet femtosecond laser treatment of the cornea is safe for intraocular tissues. Transmitted light including stray light induces no photochemical effects in lens or retina at energy levels much higher than required for the clinical purpose. These conclusions cannot be applied to eyes with pre-existing retinal damage, as these may be more vulnerable to light.
authors.affiliation: Department of Ophthalmology, University of Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Menzel-Severing
authors.affiliation: Department of Ophthalmology, University of Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: Corinna
authors.initials: C
authors.lastname: Petsch
authors.affiliation: Department of Ophthalmology, University of Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: Theofilos
authors.initials: T
authors.lastname: Tourtas
authors.affiliation: Department of Ophthalmology, University of Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: Naresh
authors.initials: N
authors.lastname: Polisetti
authors.affiliation: WaveLight GmbH, Erlangen, Germany.
authors.forename: Jörg
authors.initials: J
authors.lastname: Klenke
authors.affiliation: WaveLight GmbH, Erlangen, Germany.
authors.forename: Katrin
authors.initials: K
authors.lastname: Skerl
authors.affiliation: WaveLight GmbH, Erlangen, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Wüllner
authors.affiliation: WaveLight GmbH, Erlangen, Germany.
authors.forename: Christof
authors.initials: C
authors.lastname: Donitzky
authors.affiliation: Department of Ophthalmology, University of Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: Friedrich E
authors.initials: FE
authors.lastname: Kruse
authors.affiliation: Department of Ophthalmology, University of Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: Jan
authors.initials: J
authors.lastname: Kremers
authors.affiliation: Department of Ophthalmology, University of Erlangen-Nuremberg, Erlangen, Germany; Department of Anatomy II, University of Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: Christian M
authors.initials: CM
authors.lastname: Hammer
mesh_terms: D000818:Animals; D002386:Cataract / Q000209:etiology*; D048988:Corneal Surgery, Laser / Q000009:adverse effects* / Q000379:methods; D005260:Female; D011817:Rabbits; D014466:Ultraviolet Rays / Q000009:adverse effects*