D R Geruschat¹, S E Hassan¹, K A Turano²
¹Maryland School for the Blind/Johns Hopkins Wilmer Eye Institute, Lions Vision Research Center, Baltimore, United States; ²Johns Hopkins/Wilmer Eye Institute, Lions Vision Research Center, Baltimore, United States
Introduction: Mobility instructors have developed sequences of visual behavior to ensure safe crossing of the street. One specific aspect is the scanning sequence of looking to the near lane, far lane, then again to the near lane prior to stepping into the street. The purpose of this study was to evaluate the scanning sequence of pedestrians who have not had mobility instruction to determine if they follow this sequence of near lane, far lane, near lane.
Method: The subjects included fully sighted and low vision subjects with age-related macular degeneration, and glaucoma. Visual acuity and visual field ranged from mild to severe loss. Subjects crossed two streets, a complex light controlled plus intersection and a large roundabout. Head and eye behavior were recorded through a portable head-mounted tracking system.
Results: Results of this study demonstrate that both fully sighted and low vision subjects look to the near lane immediately before stepping into the street. However, as visual acuity decreases, and as visual field extent becomes severely constricted, subjects do not look to the near right lane as they approach the middle of the street. This finding suggests that persons with advanced low vision could increase safety through mobility instruction.
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