Luning is a detrimental visual effect characterized by a subjective darkening of the visual field in the monocular regions of partial binocular overlap displays. The effect of a number of factors on the magnitude of luning was investigated. These factors included: (1) convergent and divergent display modes for presenting partial binocular overlap field of views, (2) the field of view (FOV) luminance level, (3) the placement of either black or white contours on the binocular/monocular border, and (4) the lowering or raising of the luminance of the monocular side regions relative to the binocular overlap region. Eighteen Army aviators served as subjects in a repeated measures design. The results indicated the following. The divergent display mode systematically induced more luning than the convergent display mode under the null contour (no contours on the binocular/monocular border) condition. Adding black contours reduced luning by a roughly equivalent amount in both the convergent and divergent display modes leaving the convergent mode with less luning. The FOV luminance level had no effect on luning for the null or black contour conditions. Adding white contours, reduced luning by an amount which depended on FOV luminance, where there was less luning for lower FOV luminance levels, but no systematic effect of display mode. Changing the luminance of the monocular regions (relative to the binocular overlap region) reduced the amount of luning, with a decrease in luminance producing more of a reduction in luning than an increase in luminance. When a partial binocular overlap display overlap region) reduced the amount of luning, with a decrease in luminance producing more of a reduction in luning than an increase in luminance.

Luning is a detrimental visual effect characterized by a subjective darkening of the visual field in the monocular regions of partial binocular overlap displays. The effect of a number of factors on the magnitude of luning was investigated. These factors include: (1) The convergent versus the divergent display modes for presenting a partial binocular overlapping field-of-view; (2) The display luminance level; (3) The placement of either black or white contours versus no (null) contours on the binocular overlap border; and (4) The increasing or decreasing of the luminance of the monocular side regions relative to the binocular overlap region. Eighteen Army student aviators served as subjects in a repeated measures design. The percentage of time luning was seen was the measure of the degree of luning. The results indicated that the divergent display mode systematically induced more luning than the convergent display model under the null contour condition. Adding black contours reduced luning in both the convergent and divergent display modes, where the convergent mode retained its relatively lower magnitude of luning. The display luminance level had no effect on luning for the null or black contour conditions.