Contrast sensitivity in a dynamic environment: effects of target conditions and visual impairment

Contrast sensitivity was determined as a function of target velocity (0 degrees - 120 degrees/s) over a variety of viewing conditions. In Experiment 1, measurements of dynamic contrast sensitivity were determined for 24 male and 24 female observers as a function of target velocity for letter stimuli of 2 sizes and 2 durations. Significant main effects were found for target velocity, target size, and target duration, but significant interactions among the variables indicated especially pronounced adverse effects of increasing target velocity for small targets and brief durations. In Experiment 2, the effects of simulated cataracts on dynamic contrast sensitivity were determined for 10 male and 10 female observers. Although the simulated impairment had no effect on traditional acuity scores, dynamic contrast sensitivity was markedly reduced under all conditions but especially with the smaller targets and at higher velocities. Results are discussed in terms of dynamic contrast sensitivity as a useful composite measure of visual functioning that may provide a better overall picture of an individual's visual functioning than does traditional static acuity, dynamic acuity, or contrast sensitivity alone. The measure of dynamic contrast sensitivity may increase understanding of the practical effects of various conditions, such as aging or disease, on the visual system, or it may allow improved prediction of individuals' performance in visually dynamic, situations, such as driving and sports.