The Thulium Fiber Laser(Tm-F) is currently studied as an alternative to the Holmium:YAG laser(Ho:YAG), the gold-standard for endocorporeal laser lithotripsy. We aimed to evaluate the ex vivo effects of an accidental Tm-F laser exposure on bovine eyes and to test the protective action of different eyeglasses in preventing eye lesions in case of accident.
A 50W-TFL-generator(IPG Photonics®, Russia) with a wavelength of 1940nm and 200µm-core-diameter-fibers(CDF) were used. The laser fiber tip was pointed perpendicularly at different distances(0, 1, 3, 5, 8, 10, respectively) to the pupil center of the bovine eye. The Tm-F laser was activated for 1 or 3 seconds at three different settings(0.5J-20Hz, 1J-10Hz, and 2J-10Hz, respectively). The experiment was repeated using laser safety glasses and eyeglasses. After lasering, eye samples were immersed in a 0,5 % fluorescein serum (Faure-Ciba-Geigy®, Switzerland), then rinsed with saline solution. White- and blue-light examinations looked for localized epithelial burns(LEB), extended epithelial burns(EEB), superficial corneal ulcerations(SCU) and deep corneal ulcerations(DCU).
A total of 68 bovine eyes were used. Despite the laser settings, both DCU(contact) and SCU (1cm) developed without eye protection, for 1 and 3 seconds of lasering. At 3cm fiber-eye distance, only burning lesions were observed. Over 5cm, no lesion was found. At contact or 1 cm fiber-eye distance, pulse energy did not change lesion grade, but at 3cm, high pulse energy led to higher grade corneal lesions(0,5J-10Hz:LEB; 1J-10Hz:EEB). Despite the fiber-eye distance, no corneal lesions were reported in the laser safety glasses or eyeglasses groups for 1 second laser exposure.
Our study highlights the risk of eye damage caused by Tm-F. Without proper eye protection Tm-F can cause corneal lesions up to 5cm in distance for 1 second of exposure, despite laser settings. Only dedicated protective eyeglasses are effective for long exposures.
Journal of endourology. 2022 Mar 04 [Epub ahead of print]
Frederic Panthier, Paul Chiron, Cyril Gorny, Laurent Berthe, Steeve Doizi, Mariela Corrales, Olivier Traxer
Sorbonne Universite, 27063, GRC n°20, Groupe de Recherche Clinique sur la Lithiase Urinaire, Hôpital Tenon, Sorbonne Université, 75020, Paris, France., Paris, Île-de-France, France., Hôpital Tenon, Urology, Paris, France; ., Process and Engineering in Mechanics and Materials laboratory (PIMM), UMR CNRS/ENSAM 8006, Paris, France; ., Process and Engineering in Mechanics and Materials laboratory (PIMM), UMR CNRS/ENSAM 8006, Paris, France; ., Tenon Hospital, Assistance-Publique Hôpitaux de Paris, Urology, 4 rue de la Chine, Paris, France, 75020; ., Hospital Tenon, 55705, Urology, 4 Rue de la Chine, Paris, Île-de-France, France, 75020; ., Tenon Hospital, Assitance Publique-Hopitaux De Paris. Pierre Et Marie Curie University, Paris 6, Urology, 4 rue de la Chine, Paris, France, 75020; .
PubMed http://www.ncbi.nlm.nih.gov/pubmed/35243901
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