Effects of visual fields on standing balance

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DESCRIPTION (provided by applicant): Age-related vision impairments are a well-acknowledged risk factor for geriatric falls. The goal of the proposed pilot research is to determine the importance of central and peripheral visual field loss on the ability to integrate balance-related sensory information during standing in young and older adults. Two types of visual field loss will be considered: a) sudden occlusion of the central and peripheral visual fiel loss through the use of specially-designed contact lenses in healthy young and older adults, and b) chronic central and peripheral visual field loss in older patients with age-related macular degeneration (AMD) and glaucoma. Our first hypothesis is that peripheral vision dominates over central vision in postural stabilization, particularly in older adults (Aim #1). This will be teste using contact lenses to occlude peripheral or central vision in healthy young and older adults, thus inducing a model of acute of peripheral or central vision loss. Our second hypothesis is that the ability to integrate sensory information important for balance will be different between older patients (AMD or glaucoma) and healthy older participants with acute central or peripheral visual losses (Aim #2). This can be attributed to central adaptation processes found in patients. Three groups of participants between the ages of 65 and 85 years will be recruited for participation: (1) ten healthy subjects screened for ocular pathologies, (2) ten patients with advanced AMD, (3) ten patients with advanced glaucoma. Additionally, ten young subjects between the ages of 25 and 35 years will participate in the proposed experiments. All subjects will be screened for clinically significant conditions that impact balance. Eligible subjects will undergo both well- established and novel balance tests. Appropriately constructed mixed linear statistical models will be fit to each of the balance variables of interest to determine the impact of acute and chronic visual field losses on the ability to integrate balance-related sensory information during standing.