Abstract
Abstract: :
Purpose: To determine in a population-based sample of older adults the association between visual field loss and measures of orientation and mobility (O & M) performance and to identify the specific regions of the visual field that are more strongly associated with O & M performance. Methods: A population-based sample of 1505 persons between the ages of 72 - 92 was enrolled in the third round of SEE. Monocular visual fields (60° radius) were tested with the 81-point, single intensity (24 dB) screening test strategy on the Humphrey Field Analyzer. Binocular visual fields were estimated from a combination of the monocular fields. The square root of the number of points missed was calculated for the overall visual field and for 3 non-overlapping regions: central (<= 20°), upper- and lower-peripheral visual fields. Orientation and mobility performance were evaluated by travel time, number of bumps, and number of orientation problems on a circuitous, 32.8-m course seeded with obstacles. Log-linear regressions and linear regressions, adjusting for age, gender, body mass, height, cognitive and general health status, were performed. Results: Loss in the overall visual field was associated with an increase in the number of bumps and travel time. A 25% reduction in the number of points seen in the central visual field was associated with a 1.6-fold increase in the average number of bumps and a 12% increase in average travel time. The same percentage of points missed in the lower peripheral field was associated with a 1.5-fold increase in the average number of bumps and a 10% increase in average travel time. Visual field loss was not associated with orientation problems. Conclusion: In an older population, visual field is significantly associated with mobility performance, with losses in the central and lower-peripheral regions more important than losses in the upper-peripheral field.
Keywords: 309 aging • 355 clinical (human) or epidemiologic studies: risk factor assessment • 624 visual fields