5 March 2007 Histological aspects of retinal damage following exposure to pulsed Nd:YAG laser radiation in rabbits: indication for mechanism
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Proceedings Volume 6426, Ophthalmic Technologies XVII; 642622 (2007) https://doi.org/10.1117/12.700284
Event: SPIE BiOS, 2007, San Jose, California, United States
Abstract
The severity and characteristics of retinal injury following laser radiation derived from laser and tissue related factors. We have previously shown that retinal damage following Nd:YAG Q-switched laser radiation in rabbits was related to physical parameters, i.e. energy levels and number of pulses. Yet, an extremely large variability in the severity of the damage was found under similar exposure paradigms, even within the same retina. This emphasizes the role of the biological variables in the pathological mechanism of laser-induced retinal damage. The aim of the present study was to further study histological parameters of the injury in relation to retinal site and to elucidate their role in the initiation and characteristics of the damage, following various energy levels (10-50 &mgr;J) and number of pulses (1-4). Pigmented rabbits were exposed to Nd:YAG laser radiation (532nm, pulse duration: 20ns). Exposures were conducted in retina tissue, adjacent to the optic nerve, with a total of 20 exposures per retina. Animals were sacrificed 15 min or 24 hours post exposure, eyes enucleated and processed for paraffin embedding. 4&mgr;m thick serial sections, stained with hematoxylin and eosin, were examined under light microscopy. Two major types of retinal damage were observed: focal edema confined to the pigmented epithelium and the photoreceptor cells, and hemorrhages, associated with destruction of retinal tissue. While focal edema associated with slight elevation of the photoreceptor layer seems to depend on the pigmented epithelium, hemorrhages were related also to the choroid vasculature at the site of radiation. It is suggested that a thermo-mechanical mechanism is involved in laser induced retinal hemorrhages at energies above 10-30&mgr;J (2-1 pulses, respectively).
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T. Kadar, D. Peri, J. Turetz, E. Fishbine, R. Sahar, I. Egoz, N. Sapiens, R. Brandeis, "Histological aspects of retinal damage following exposure to pulsed Nd:YAG laser radiation in rabbits: indication for mechanism", Proc. SPIE 6426, Ophthalmic Technologies XVII, 642622 (5 March 2007); doi: 10.1117/12.700284; https://doi.org/10.1117/12.700284
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