• Jasmine C Menant, Rebecca J St George, Blake Sandery, Richard C Fitzpatrick, and Stephen R Lord.
• Prince of Wales Medical Research Institute, University of New South Wales, New South Wales, Australia.
• J Am Geriatr Soc. 2009 Oct 1; 57 (10): 1833-8.

ObjectivesTo 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.DesignRandomized order, cross-over, controlled comparison.SettingFalls laboratory, medical research institute.ParticipantsThirty community-living adults aged 65 and older.MeasurementsObstacle 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.ResultsWhen 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).ConclusionThe 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.

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