Abstract
Collecting high-quality psychophysical data to estimate contrast sensitivity in human and animal subjects is typically time-intensive and requires extensive training. New tasks requiring continuous tracking of targets are fairly intuitive, require little training and are a much faster way to collect a large amount of data. By design, these tasks assess behavioral performance at the center of gaze. In order to test both foveal and peripheral vision we used a visual search task to obtain quick and reliable estimates of contrast sensitivity. We presented targets of variable spatial frequency and contrast at a variable distance from the center of gaze, and required the subject to acquire the target. This task requires virtually no training, granted that the subject is accustomed to orienting towards a monitor and is able to perform well-controlled eye movements. To evaluate the effectiveness of our task at measuring visual function for a variety of cases, we collected data from adult humans and macaque monkeys in different stages of visual development. We also collected data monocularly from an adult amblyopic macaque monkey. We compared contrast sensitivities as a function of age, amblyopia, or distance from the center of gaze. For the human subjects we compared the resulting sensitivities with ones obtained with a two alternative forced choice task (2AFC). Qualitatively, our findings suggest that the visual search task produces reasonable results. We confirmed that contrast sensitivity increases throughout development, the amblyopic eye is less sensitive than the fellow eye, and sensitivity in the periphery is poorer than near the center of gaze. We propose that this visual search task can be used to quickly estimate contrast sensitivity. This is particularly useful for testing challenging populations such as young children or young animals.