title: Corneal shaping and ablation of transparent media by femtosecond pulses in deep ultraviolet range.
abstract: OBJECTIVE
  To assess the performance of a newly developed solid-state femtosecond ultraviolet (UV) laser system in corneal ablation.
  
  
  METHODS
  Vilnius University, Laser Research Centre, Vilnius, Lithuania.
  
  
  METHODS
  Femtosecond pulses in the deep UV range (205 nm) were obtained by the generation of the fifth-harmonic of an amplified Yb:KGW laser system (fundamental output at 1027 nm). Coupled with galvanometric beam-scanning mirrors, this system allowed ablation shaping of transparent media, including poly(methyl methacrylate) (PMMA), collagen, and ex vivo porcine corneas. The surfaces of ablated structures were characterized using a noncontact confocal optical profiler.
  
  
  RESULTS
  Spherical structures were successfully formed in all 3 materials tested. A 10.0 diopter refraction change in the cornea was produced in 180 seconds. The resulting surface quality was significantly higher (roughness length >100 microm versus approximately 6 microm) in gelatin and ex vivo corneas than in PMMA.
  
  
  CONCLUSIONS
  The solid-state femtosecond UV laser system seems an attractive alternative to the currently used ophthalmic argon-fluoride excimer laser system because of its small footprint, silent operation, and ability to generate femtosecond light pulses at both 1027 nm (suitable for flap creation) and 205 nm (corneal ablation).
authors.affiliation: Faculty of Physics, Laser Research Centre, Faculty of Natural Sciences, Vilnius University, Vilnius, Lithuania. mikas.vengris@ff.vu.lt
authors.forename: Mikas
authors.initials: M
authors.lastname: Vengris
authors.forename: Egle
authors.initials: E
authors.lastname: Gabryte
authors.forename: Aidas
authors.initials: A
authors.lastname: Aleknavicius
authors.forename: Martynas
authors.initials: M
authors.lastname: Barkauskas
authors.forename: Osvaldas
authors.initials: O
authors.lastname: Ruksenas
authors.forename: Agne
authors.initials: A
authors.lastname: Vaiceliunaite
authors.forename: Romualdas
authors.initials: R
authors.lastname: Danielius
mesh_terms: D000818:Animals; D003094:Collagen; D003315:Cornea / Q000601:surgery*; D048988:Corneal Surgery, Laser / Q000295:instrumentation*; D008954:Models, Biological; D019904:Polymethyl Methacrylate; D013524:Surgical Flaps; D013552:Swine; D014466:Ultraviolet Rays
chemical_list: D003094:Collagen; D019904:Polymethyl Methacrylate