Laser Glare in the Cockpit: Psychophysical Estimates versus Model Predictions of Veiling Luminance Distribution

Two methods for estimating the visual effects of light scattered from a laser glare source were compared: (1) a veiling luminance (VL) model that convolves a radiometric scan of the corneal light distribution with a point-spread function to calculate the retinal distribution and (2) psychophysically determined equivalent background luminance (EBL). For six subjects, detection thresholds for a 12-arc-min-diameter test spot were measured at 24 points in the glare field (4 quadrants x 6 eccentricities between 0.25 and 8 deg). Measured Weber fractions were used to calculate EBL's for each test point. Output of the VL model matched the EBL data well, but underestimated the EBL at the smallest (0.25-deg) eccentricity and overestimated it at eccentricities from 1 to 4 deg. This model can be a useful predictor of visual decrements in a variety of glare situations.