Nd: YAG laser irradiation of an eye model: Experimental analysis

✍ Scribed by F. Docchio; Prof. Carlo A. Sacchi

• Publisher: John Wiley and Sons
• Year: 1987
• Tongue: English
• Weight: 900 KB
• Volume: 6
• Category: Article
• ISSN: 0196-8092
• DOI: 10.1002/lsm.1900060607

✦ Synopsis

This work reviews a series of experiments performed on an eye model to study physical effect relevant for a safe and effective use of the Q-switched Nd:YAG laser in ophthalmic microsurgery. The breakdown probability per laser pulse has been found to depend exponentially on the reciprocal laser field. This indicates that. as in trasparent solids. electron avalanche ionization is likely the main mechanism for optical breakdown in liquids. Shielding of the retina, by the laserinduced plasma, is not very effective, but an appreciable degree of shielding is present, in burst operation, even after membrane disruption. A backscattered beam, which presents the typical properties of stimulated Brillouin scattering, has been observed in the eye model, with a threshold of -5*109 W/cm2. This beam, which presents an irregular spatial structure with peaks of irradiance well above the average value, may produce damage of the internal wall of the cornea.