Reciprocity of Intensity and Duration on the Dark Adaptation Effects of Light Pulses

: This report addressed two questions. First, over what durations and intensities do light exposure of equal energy appear equally bright? Second, do light exposures of equal energy have equivalent effects on the course of dark adaptation? These questions were addressed to refine the AFRL/HEDO flashblindness model. These studies show that reciprocity between duration and intensity is the exception rather than the rule for dark adaptation. The evidence indicates that reciprocity can be expected from about 100 ms to about 10 ms. A study linking a range of short duration exposures from nanoseconds to milliseconds is lacking. During the initial stage of dark adaptation, different duration exposures have very different initial thresholds and recovery functions. From the standpoint of modeling, for exposure durations less than 10 ms, dark adaptation could be described by a single dark adaptation function. Modern lasers now make it possible to study very short duration exposures.