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Proceedings Paper

Laser-induced retinal damage thresholds for annular retinal beam profiles
Author(s): Paul K. Kennedy; Joseph A. Zuclich; David J. Lund; Peter R. Edsall; Stephen Till; Bruce E. Stuck; Richard C. Hollins
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Paper Abstract

The dependence of retinal damage thresholds on laser spot size, for annular retinal beam profiles, was measured in vivo for 3 μs, 590 nm pulses from a flashlamp-pumped dye laser. Minimum Visible Lesion (MVL)ED50 thresholds in rhesus were measured for annular retinal beam profiles covering 5, 10, and 20 mrad of visual field; which correspond to outer beam diameters of roughly 70, 160, and 300 μm, respectively, on the primate retina. Annular beam profiles at the retinal plane were achieved using a telescopic imaging system, with the focal properties of the eye represented as an equivalent thin lens, and all annular beam profiles had a 37% central obscuration. As a check on experimental data, theoretical MVL-ED50 thresholds for annular beam exposures were calculated using the Thompson-Gerstman granular model of laser-induced thermal damage to the retina. Threshold calculations were performed for the three experimental beam diameters and for an intermediate case with an outer beam diameter of 230 μm. Results indicate that the threshold vs. spot size trends, for annular beams, are similar to the trends for top hat beams determined in a previous study; i.e., the threshold dose varies with the retinal image area for larger image sizes. The model correctly predicts the threshold vs. spot size trends seen in the biological data, for both annular and top hat retinal beam profiles.

Paper Details

Date Published: 1 July 2004
PDF: 9 pages
Proc. SPIE 5319, Laser Interaction with Tissue and Cells XV, (1 July 2004); doi: 10.1117/12.529400
Show Author Affiliations
Paul K. Kennedy, Air Force Research Lab. (United States)
Joseph A. Zuclich, Northrop Grumman Corp. (United States)
David J. Lund, U.S. Army Medical Research Detachment (United States)
Peter R. Edsall, Northrop Grumman Corp. (United States)
Stephen Till, Defense Science and Technology Lab. (United Kingdom)
Bruce E. Stuck, U.S. Army Medical Research Detachment (United States)
Richard C. Hollins, Defense Science and Technology Lab. (United Kingdom)


Published in SPIE Proceedings Vol. 5319:
Laser Interaction with Tissue and Cells XV
Steven L. Jacques; William P. Roach, Editor(s)

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