Visual correlates of obstacle avoidance in adults with low vision.

This study examined how mobility performance in a heterogeneous sample of visually impaired adults relates to measures of visual sensory and perceptual function. We found that the best predictors of mobility performance under photopic and scotopic lighting conditions were models that incorporated visual field extent (VFE) and scanning ability. Together with measures of contrast sensitivity and spatial resolution, these models accounted for approximately 50% of the variance in mobility performance. We also found that VFE and scanning ability were the dominant predictor variables when the sample was broken down by subjects' type of vision loss into an acuity loss, a visual field restriction, and a combination loss group.