We have measured the retinal damage threshold for a large spot size, multiple-pulse exposure to a Q-switched, frequency-double Nd:YAG laser (532 nm, 7 ns pulses). A 500 μm diameter retinal beam spot was used. The ED50, expressed as the per-pulse energy, varies only weakly with the number of pulses, n, for this extended spot size. The previously reported threshold for a multiple-pulse exposure for a 900 μm retinal spot size also shows the same weak dependence on the number of pulses. The multiple-pulse ED50 for an extended spot-size exposure does not follow the n-1/4 dependence exhibited by small spot size exposures produced by a collimated beam.

Topics
Lasers, Vitamins
1.
American National Standard Institute (ANSI)
(
2007
),
American National Standard for Safe Use of Lasers
,
Laser Institute of America
.
2.
Stuck
,
B.E.
,
Lund
,
D.J.
 &
Beatrice
,
E.S.
 (
1978
)
Repetitive Pulse Laser Data and Permissible Exposure Limits, Letterman Army Institute of Research Report No. 58
.
3.
Walkenbach
,
J.E.
 (
1972
)
Determination of Retinal Lesion Threshold Energies of Pulse Repetition Nd+3:YAG Laser in the Rhesus Monkey
, Master’s Thesis,
Virginia Commonwealth University
.
Google Scholar
 
4.
Griess
,
G.A.
,
Blankenstein
,
M.F.
 &
Williford
,
G.G.
 (
1980
)
Ocular Damage from Multiple-Pulse Laser Exposures
,
Health Physics
39
,
921
–
927
.
https://doi.org/10.1097/00004032-198012000-00005
Google Scholar
Crossref
Search ADS
PubMed
 
5.
Lund
,
B.J.
 (
2006
)
The ProbitFit Program to Analyse Data from Laser Damage Threshold Studies, Walter Reed Army Institute of Research Report No. 06/001
.
6.
Menendez
,
A.R.
,
Cheney
,
F.E.
,
Zuclich
,
J.A.
 &
Crump
,
P.
 (
1993
)
Probability-Summation Model of Multiple Laser-Exposure Effects
,
Health Physics
65
,
523
–
528
.
https://doi.org/10.1097/00004032-199311000-00008
Google Scholar
Crossref
Search ADS
PubMed
 
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