Waterloo Vision and Mobility Study: Normal gait characteristics during dark and light adaptation in individuals with age-related maculopathy

The purpose of this study was to evaluate the gait responses of individuals with low vision compared to those of normal-visioned individuals when their vision is challenged by extreme levels of light. Twenty subjects with age-related maculopathy (ARM) and 20 subjects with normal vision first walked along a flat, unobstructed path immediately after the ambient light level was changed from low (5 lux) to high (2500 lux). The procedure was repeated after the light was reduced from the high to the low level. Muscle activity, temporal and kinematic variables, and ground reaction forces were used to detect gait characteristics because of ambient light level changes. Data suggested that ARM subjects walked slower and with more caution than normal subjects but that these differences were not related to ambient light level. Head angle, an estimate of gaze direction, was lower for ARM subjects during high light, but the gaze direction for both groups was low during low light. Among these ARM subjects, extreme levels of ambient light did not affect gait; subjects made adaptations that were reasonable to encourage safe ambulation, despite the direction of light change. Normal-visioned individuals in this study experienced more difficulty in low light than high light situations.