On the time dependence of the laser-induced retinal injury thresholds in the nanosecond to millisecond time domain

Abstract

The wavelength dependence of the MPE for retinal laser exposure to durations greater than 1 ns have remained essentially unchanged since the 1970’s (ANSI, ICNIRP, IEC)[1-3] and remained unchanged when guidance was included in 2000 for exposure durations less than 1 ns. Recent studies have measured laser-induced retinal injury thresholds only a factor of 3 higher than the MPE for point-source exposure in NHP eyes for 3-5 ns duration exposures at 532 nm and, in fact, if the incident beam subtends a visual angle α of 5 mrad, the injury threshold is nearly equal to the MPE for α = 5 mrad. This paper examines existing in vivo and in vitro laser-induced retinal injury data for ns to ms duration exposures to determine if a change in the guidelines should be considered.The wavelength dependence of the MPE for retinal laser exposure to durations greater than 1 ns have remained essentially unchanged since the 1970’s (ANSI, ICNIRP, IEC)[1-3] and remained unchanged when guidance was included in 2000 for exposure durations less than 1 ns. Recent studies have measured laser-induced retinal injury thresholds only a factor of 3 higher than the MPE for point-source exposure in NHP eyes for 3-5 ns duration exposures at 532 nm and, in fact, if the incident beam subtends a visual angle α of 5 mrad, the injury threshold is nearly equal to the MPE for α = 5 mrad. This paper examines existing in vivo and in vitro laser-induced retinal injury data for ns to ms duration exposures to determine if a change in the guidelines should be considered.