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Proceedings Paper

Retinal damage following exposure to pulsed Nd:YAG laser radiation in rabbits and its relation to physical parameters
Author(s): Rachel Brandeis; David Peri; Josef Turetz; Eliezer Fishbine; Inbal Egoz; Tamar Kadar
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Paper Abstract

The aim of the present study was to characterize permissible exposure limits (MPE) for safety analysis, with an emphasis on the immediate retinal damage, following Nd:YAG Q-switched laser radiation, and to test its correlation to physical parameters. Pigmented rabbits were exposed to Nd:YAG laser radiation (532nm, pulse duration: 20ns) in various energies. Exposures were conducted in retina tissue, very close to the optic nerve, with a total of 20 exposures per retina. Retinas were viewed during the first 10 min following exposure, using an on-line digital video camera. Thereafter, animals were sacrificed for histological evaluation. A part of the retinas were evaluated 24 hours post exposure. A quantitative analysis of the clinical findings, based on a severity score scale and a morphometric analysis of the extent of the lesions, was used to test the statistical relationship with the laser energy and number of pulses. In addition, hemorrhage threshold values were computed using Probit Analysis. Retinal damage, at various levels of severity, was observed immediately after exposure to energies above 10μJ, characterized by edema and subretinal hemorrhages. The appearance and severity of the lesions varied among animals, between fellow eyes and even within the same retina. The relationship between severity and extent of lesions, and energy levels and number of pulses was evaluated. The ED50 for various, immediate types of hemorrhage was determined, and correlated to physical parameters. Histological observations strengthened the clinical findings. The results were discussed in accordance with photomechanical and thermal theories of laser-tissue interactions.

Paper Details

Date Published: 18 April 2005
PDF: 11 pages
Proc. SPIE 5688, Ophthalmic Technologies XV, (18 April 2005); doi: 10.1117/12.588567
Show Author Affiliations
Rachel Brandeis, Israel Institute for Biological Research (Israel)
David Peri, Israel Institute for Biological Research (Israel)
Josef Turetz, Israel Institute for Biological Research (Israel)
Eliezer Fishbine, Israel Institute for Biological Research (Israel)
Inbal Egoz, Israel Institute for Biological Research (Israel)
Tamar Kadar, Israel Institute for Biological Research (Israel)

Published in SPIE Proceedings Vol. 5688:
Ophthalmic Technologies XV
Fabrice Manns; Bruce E. Stuck; Michael Belkin M.D.; Per G. Söderberg; Arthur Ho, Editor(s)

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