Visual Impairment and Mobility Performance in Older Adults
Visual Impairment and Mobility Performance in Older Adults
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). However, 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.
Walking speed is a strong predictor of disability and death in older adults. As a result, walking speeds have been used as an indicator of health and functioning in elderly populations. Previous research has shown that mobility declines with age, including declines in walking speeds on flat surfaces, as well as stair ascent and descent speeds. Examining factors that affect mobility at older ages is an important step toward preventing or postponing mobility disability.
Declines in the mobility performance of older adults are thought to be primarily a result of the accumulation of health conditions at older ages. Visual impairment is 1 condition that has been shown in cross-sectional studies to negatively affect walking speeds among older adults. However, we do not know how vision loss affects walking speeds over time. Increasing our understanding of how mobility changes in visually impaired (VI) older adults compared with non–visually impaired (NVI) older adults may guide prevention and intervention strategies aimed at minimizing the impact of visual impairment.
Therefore, the primary goal of this study was to determine how visual impairment status affects changes in walking speed over an 8-year period. We hypothesized that the VI will have a more rapid decline in walking speeds on stairs and a flat surface than the NVI over the study period, and we aimed to determine whether visual impairment exacerbates the decline in walking speeds as people age. The secondary aims of this study were to determine whether the VI are more likely than the NVI to be classified as having mobility disability and whether changes in the odds of mobility disability will be greater over time in the VI.
Abstract and Introduction
Abstract
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). However, 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.
Introduction
Walking speed is a strong predictor of disability and death in older adults. As a result, walking speeds have been used as an indicator of health and functioning in elderly populations. Previous research has shown that mobility declines with age, including declines in walking speeds on flat surfaces, as well as stair ascent and descent speeds. Examining factors that affect mobility at older ages is an important step toward preventing or postponing mobility disability.
Declines in the mobility performance of older adults are thought to be primarily a result of the accumulation of health conditions at older ages. Visual impairment is 1 condition that has been shown in cross-sectional studies to negatively affect walking speeds among older adults. However, we do not know how vision loss affects walking speeds over time. Increasing our understanding of how mobility changes in visually impaired (VI) older adults compared with non–visually impaired (NVI) older adults may guide prevention and intervention strategies aimed at minimizing the impact of visual impairment.
Therefore, the primary goal of this study was to determine how visual impairment status affects changes in walking speed over an 8-year period. We hypothesized that the VI will have a more rapid decline in walking speeds on stairs and a flat surface than the NVI over the study period, and we aimed to determine whether visual impairment exacerbates the decline in walking speeds as people age. The secondary aims of this study were to determine whether the VI are more likely than the NVI to be classified as having mobility disability and whether changes in the odds of mobility disability will be greater over time in the VI.
