title: Do We Really Need to Wear Proper Eye Protection When Using Holmium:YAG Laser During Endourologic Procedures? Results from an Ex Vivo Animal Model on Pig Eyes.
abstract: OBJECTIVE
  We sought to evaluate the effect of holmium:yttrium-aluminum-garnet (Ho:YAG) laser exposure on ex vivo pig eyes and to test the protective action of different glasses in preventing eye lesions in case of accident.
  
  
  METHODS
  We pointed the tip of a Ho:YAG laser fiber from different distances (0, 3, 5, 8, 10, and 20 cm, respectively) toward the center of the pupil of the pig eye. The Ho:YAG laser was activated for 1 or 5 seconds at three different settings (0.5 J-20 Hz, 1 J-10 Hz, and 2 J-10 Hz, respectively). The experiment was repeated using laser safety glasses and eyeglasses. A total of 78 pig eyes were used. The effects of the Ho:YAG laser on pig eyes were assessed by histopathology. Comparable laser emission experiments were performed on thermal paper at different distances using different pulse energies.
  
  
  RESULTS
  Ho:YAG laser-induced corneal lesions were observed in unprotected eyes, ranging from superficial burning lesions to full-thickness necrotic areas, and were directly related to pulse energy and time of exposure and inversely related to the distance from the eye. When the laser was placed 5 cm or more, no corneal damage was observed regardless of the laser setting and the time of exposure. Similar distance/energy level relationships were observed on thermal paper. No damage was observed to the lens or the retina in any of the Ho-YAG laser-treated eyes or in any of the eyes protected by laser safety and eyeglasses.
  
  
  CONCLUSIONS
  Ho:YAG lasers can cause damage when set to high energy, but only to the cornea, from close distances (0-5 cm) and in the absence of eye protection. Eyeglasses are equally effective in preventing laser damage as laser safety glasses.
authors.affiliation: 1 Department of Urology, Tenon Hospital, Pierre and Marie Curie University , Paris, France .|2 Division of Experimental Oncology/Unit of Urology, URI , IRCCS Ospedale San Raffaele, Milan, Italy .
authors.forename: Luca
authors.initials: L
authors.lastname: Villa
authors.affiliation: 1 Department of Urology, Tenon Hospital, Pierre and Marie Curie University , Paris, France .
authors.forename: Jonathan
authors.initials: J
authors.lastname: Cloutier
authors.affiliation: 3 Department of Pathology, Pitié-Salpêtrière Hospital, Pierre and Marie Curie University , Paris, France .
authors.forename: Eva
authors.initials: E
authors.lastname: Compérat
authors.affiliation: 4 Department of Urology, Hospital Prof. Doutor Fernando Fonseca , Amadora, Portugal .
authors.forename: Peter
authors.initials: P
authors.lastname: Kronemberg
authors.affiliation: 3 Department of Pathology, Pitié-Salpêtrière Hospital, Pierre and Marie Curie University , Paris, France .
authors.forename: Frederic
authors.initials: F
authors.lastname: Charlotte
authors.affiliation: 5 Process and Engineering in Mechanics and Materials Laboratory (PIMM) , UMR CNRS/ENSAM 8006, Paris, France .
authors.forename: Laurent
authors.initials: L
authors.lastname: Berthe
authors.affiliation: 5 Process and Engineering in Mechanics and Materials Laboratory (PIMM) , UMR CNRS/ENSAM 8006, Paris, France .
authors.forename: Yann
authors.initials: Y
authors.lastname: Rouchausse
authors.affiliation: 2 Division of Experimental Oncology/Unit of Urology, URI , IRCCS Ospedale San Raffaele, Milan, Italy .|6 Università Vita-Salute San Raffaele , IRCCS Ospedale San Raffaele, Milan, Italy .
authors.forename: Andrea
authors.initials: A
authors.lastname: Salonia
authors.affiliation: 2 Division of Experimental Oncology/Unit of Urology, URI , IRCCS Ospedale San Raffaele, Milan, Italy .|6 Università Vita-Salute San Raffaele , IRCCS Ospedale San Raffaele, Milan, Italy .
authors.forename: Francesco
authors.initials: F
authors.lastname: Montorsi
authors.affiliation: 1 Department of Urology, Tenon Hospital, Pierre and Marie Curie University , Paris, France .
authors.forename: Olivier
authors.initials: O
authors.lastname: Traxer
mesh_terms: D000535:Aluminum; D000818:Animals; D002056:Burns / Q000209:etiology* / Q000517:prevention & control; D065306:Corneal Injuries / Q000209:etiology* / Q000517:prevention & control; D004724:Endoscopy; D005123:Eye; D005131:Eye Injuries / Q000209:etiology / Q000517:prevention & control; D005135:Eye Protective Devices; D005139:Eyeglasses; D006695:Holmium; D006801:Humans; D053844:Lasers, Solid-State / Q000009:adverse effects*; D007908:Lens, Crystalline / Q000293:injuries; D060051:Occupational Injuries / Q000209:etiology / Q000517:prevention & control; D012160:Retina / Q000293:injuries; D034421:Sus scrofa; D013552:Swine; D014572:Urology; D015019:Yttrium
chemical_list: C503779:yttrium-aluminum-garnet; D015019:Yttrium; D000535:Aluminum; D006695:Holmium