Do We Really Need to Wear Proper Eye Protection When Using Holmium:YAG Laser During Endourologic Procedures? Results from anEx VivoAnimal Model on Pig Eyes

• DOI: 10.1089/end.2015.0232
• Publication Date: 2015-10-16T08:27:34Z
• Authors: Luca Villa; Jonathan Cloutier; Eva Compérat; Peter Kronemberg; Frederic Charlotte; Laurent Berthe; Yann Rouchausse; Andrea Salonia; Francesco Montorsi; Olivier Traxer
• Keywords: Swine; Urology; Sus scrofa; Endoscopy; Lasers, Solid-State; Eye; Occupational Injuries; Retina; Holmium; 03 medical and health sciences; Eye Injuries; Eyeglasses; 0302 clinical medicine; Lens, Crystalline; Animals; Humans; Yttrium; Burns; Eye Protective Devices; Aluminum; Corneal Injuries

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.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.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.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.