A Longitudinal Study of the Association Between Visual Impairment and Mobility Performance in Older Adults: The Salisbury Eye Evaluation Study
Few longitudinal studies have examined how visual impairment affects mobility as people age.
Data from the Salisbury Eye Evaluation Study, a population-based sample of 2,520 adults aged 65 years and older, were used to investigate the longitudinal association between visual impairment and mobility.
Baseline, 2-year, 6-year, and 8-year visits occurred between 1993 and 2001.
Mobility was assessed by measuring speeds on the following 3 tasks: walking up 7 steps, walking down 7 steps, and walking 4 m. Random-effects linear regression was used to model factors affecting speed.
For each year of observation, speeds declined, and the visually impaired had significantly slower speeds than the non–visually impaired on all 3 tests after accounting for other covariates (βwalking up steps = −0.08 steps/second, 95% confidence interval (CI): −0.10, −0.06; βwalking down steps = −0.11 steps/second, 95% CI: −0.14, −0.08; and βwalking 4 m = −0.08 m/second, 95% CI: −0.10, −0.06).
The interaction between years since baseline and visual impairment status was not significant, indicating that mobility speeds declined at a similar rate in the visually impaired and the non–visually impaired. These results suggest that the impact of visual impairment on speed is significant but does not change as people age.