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Proceedings Paper

Modeling of laser-induced threshold damage in the peripheral retina
Author(s): Garrett D Polhamus; Robert J. Thomas; Rebecca M. Hall; Joseph A. Zuclich; Harry Zwick; Leon N. McLin
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Paper Abstract

Though allowable (safe) energy doses of pulsed laser radiation have been determined in the central retina, the sensitivity of the peripheral retina to damage must also be assessed. We used results from ray-tracing in an eye model to estimate laser spot size at the retina and recent thermal model computations of damage thresholds to predict off-axis retinal injury from laser irradiation. The predictions were made for threshold exposures with a 532-nm, 10-ns, Nd:YAG laser beam that filled the dilated pupil (7-mm diameter). Results were compared to previously published measured energy doses at the cornea needed to produce a minimally visible lesion (MVL) in the peripheral retina of rhesus subjects. We predicted the threshold for injury at the macula, and at selected portions of peripheral retina out to 60 degree(s) from the fovea. Both predictions and measured data were normalized to their respective macula values. Normalized predicted thresholds in the peripheral retina increased as a function of angular distance from the macula. This varied from the measured data which, on the other hand, were relatively insensitive to angular position in the peripheral retina. The difference is likely due to improvements in methods of assessing retinal injury that have been incorporated into the model.

Paper Details

Date Published: 27 June 2002
PDF: 8 pages
Proc. SPIE 4617, Laser Tissue Interaction XIII: Photochemical, Photothermal, and Photomechanical, (27 June 2002); doi: 10.1117/12.472540
Show Author Affiliations
Garrett D Polhamus, Northrop Grumman Corp. (United States)
Robert J. Thomas, Northrop Grumman Corp. (United States)
Rebecca M. Hall, Northrop Grumman Corp. (United States)
Joseph A. Zuclich, Northrop Grumman Corp. (United States)
Harry Zwick, Walter Reed Army Institute of Research (United States)
Leon N. McLin, Air Force Research Lab. (United States)

Published in SPIE Proceedings Vol. 4617:
Laser Tissue Interaction XIII: Photochemical, Photothermal, and Photomechanical
Steven L. Jacques; Donald Dean Duncan; Donald Dean Duncan; Sean J. Kirkpatrick; Sean J. Kirkpatrick; Andres Kriete; Andres Kriete, Editor(s)

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