Head and Eye Control in Persons with Low Vision during Urban Navigation.

Low vision involves a range of visual impairments that significantly impact daily activities, particularly navigation in urban environments. Individuals with low vision often develop adaptive strategies to compensate for visual deficits, relying on head movements to bring objects into their remaining functional field of vision. Research suggests that they focus on road surface markings and building edges to aid in wayfinding and collision avoidance. However, urban navigation presents additional challenges, as obstacles, moving hazards, and tripping dangers may enter their visual loss field, increasing the risk of injury. Traditional eye movement studies are typically conducted in controlled laboratory settings with fixed head positions, limiting the understanding of head-eye coordination in real-world environments. To bridge this gap, we designed a naturalistic, "free-head" experiment using eye-tracking technology to examine head and eye movement patterns during urban navigation. Participants with low vision were compared to a control cohort without visual impairment to test the hypothesis that eye and head movements become decoupled in visually impaired individuals. Findings indicate that individuals with peripheral field loss exhibit significant eye-head decoupling, while those with acuity loss demonstrate more synchronized movements. Results for individuals with central field loss were inconclusive but revealed distinct movement patterns. These insights provide valuable direction for rehabilitation strategies, assistive- mobility technologies, and urban design improvements. By expanding research on eye-head coordination, this study contributes to the development of interventions that enhance safety, mobility, and independence for individuals with low vision in complex urban environments.