Older People Contact More Obstacles When Wearing Multifocal Glasses and Performing a Secondary Visual Task.
Menant, Jasmine C. PhD *; St. George, Rebecca J. BSc (Hons) *; Sandery, Blake *; Fitzpatrick, Richard C. PhD *; Lord, Stephen R. PhD, DSc *
Journal of the American Geriatrics Society.
57(10):1833-1838, October 2009.
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OBJECTIVES: To determine whether wearing multifocal glasses affects obstacle avoidance and eye and head movements during walking with and without a secondary visual task in older people.
DESIGN: Randomized order, cross-over, controlled comparison.
SETTING: Falls laboratory, medical research institute.
PARTICIPANTS: Thirty community-living adults aged 65 and older.
MEASUREMENTS: Obstacle contacts, secondary-task errors, average head angle (HA) in pitch, and peak-to-peak pitch amplitude of the eye (PA-E) and the head (PA-H) were assessed during obstacle-only and dual-task trials that required participants to read a series of letters presented in front of them at eye level under multifocal and single-lens glasses conditions.
RESULTS: When wearing multifocal lens glasses, participants performed the obstacle-only trials more slowly (P=.004) and contacted more obstacles in the dual-task trials (P=.001) than when wearing single-lens glasses. For the dual task trials under the multifocal glasses condition, greater PA-E was associated with more obstacle contacts ([rho]=0.409, P=.02) and greater PA-H was associated with more secondary-task errors ([rho]=0.583 P=.002). Lower HA was associated with more secondary-task errors ([rho]=0.608, P=.002) and increased PA-H ([rho]=0.426, P=.02).
CONCLUSION: The findings demonstrate that older adults contact more obstacles while walking with their attention divided when wearing multifocal glasses. This is probably because of a failure to adopt a compensatory increase in pitch head movement, resulting in blurred vision of obstacles viewed through the lower segments of multifocal glasses.
(C) 2009 by the American Geriatrics Society