Laser Flash Effects on Chromatic Discrimination in Monkeys.

Detecting a camouflaged target in a visually noisy background depends on the ability of the observer to discriminate the target from the surrounding terrain. Visible laser irradiation at less than damage levels can act as a masking source by compromising or reducing the observers ability to resolve differences in the visual scene. Previous research has examined this concept by investigating laser flash effects on acuity size discrimination tracking motion discrimination visual sensitivity color and contrast sensitivity functions luminance contrast. In all cases, flashes from continuous-wave CW sources have proven more effective visually than pulsed Q-switched sources, when compared on peak energy criterion i.e., MPE, even though Q-switched lasers induce damage at lower energy doses. Additionally, the inherent safety of ultra-short laser pulses has been questioned. Past animal research has shown that, on the measures of acuity, sensitivity, tracking, and contrast detection, the animals recover to baseline if the exposure has remained below the MPE. The one measure that has not been investigated is color discrimination. The major conclusions from this investigation are a red and green colored laser flashes shift the color balance transiently in the visual system, and yellow flashes do so to a lesser extent thus targets may change both hue and brightness after an observer receives colored flashes and b Q-switched lasers, at non-lesioning levels, when equated for time-averaged perceptual brightness, have comparable effects to flashes with longer time courses.