Product Code: ILSC2009_302

Damage Threshold from Large Retinal Spot Size Repetitive-pulse Laser Exposures
Authors:
Brian Lund, Northrop Grumman; San Antonio TX USA
David Lund, Us Army Medical Research Detachment; Brooks City-Base TX USA
Peter Edsall, Northrop Grumman; San Antonio TX USA
Presented at ILSC 2009

We have measured the retinal damage threshold for large spot size, multiple-pulse exposures to a Q-switched, frequency-double Nd:YAG laser (532 nm, 7 ns pulses). A 500 m diameter retinal beam spot was used. The ED50 was determined for exposures to trains of 1, 3, 10, and 100 pulses at a pulse repetition frequency of 10 Hz. 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 mm 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.