Vision Adjustment Research Articles

The role of sensory and cognitive function in the onset of activity restriction in older people

Background: Extending healthy active life expectancy is a priority if we are to achieve gains in both the quality and quantity of life lived at older ages. We investigated the role of sensory (vision and hearing) and cognitive function on the onset of activity restriction in older people.Methods: A survey of a total population (N = 1579) of people aged 75 years and older, registered with a large general population in Melton Mowbray, Leicestershire, England, was undertaken in 1988 and linked with subsequent routine health assessments (up to a maximum of five) over 10 years. Activity restriction was defined as having difficulty performing on their own, requiring help or aids or not doing any one of seven Activities of Daily Living (ADLs). The study population comprised the 643 persons who were not restricted at baseline. Cox proportional hazard regression models were fitted to time of onset of activity restriction with those dying before activity restriction was reported being censored at time of death.Results: After adjustment for confounding factors (socio-demographic and psychosocial factors, physical health and physical functional limitations), difficulty with both vision and hearing conferred a doubling of risk of activity restriction (RR = 2.36, 95% CI 1.31 to 4.28). A unit decrease in the Information/Orientation subtest was associated with a 10% increase in risk (RR = 1.10, 95% CI 1.02 to 1.19), even after adjustment for vision and hearing as well as other confounding factors, though baseline Mini-Mental State Examination score was not indicative of increased risk (RR = 1.02, 95% CI 0.98 to 1.06).Conclusion: Differentiating whether disability is a result of physical, sensory or cognitive functional limitations, is necessary to identify need and the direction in which efforts should be targeted to improve active life expectancy in older people.

Divided visual attention as a predictor of bumping while walking: the Salisbury Eye Evaluation.

The purpose of this study was to determine the association between bumping while walking and divided visual attention, as measured by the useful field of view (UFOV). The Salisbury Eye Evaluation is a population-based study of community-dwelling adults, aged 72 to 92 at the third round of data collection. Participants walked a circuitous 32.8-m course, seeded with obstacles, and the number of bumps made while traversing the course was counted. UFOV divided attention score was based on processing speed: the time taken to identify a central target, and the location of a peripheral target simultaneously. Association between number of bumps and UFOV score was assessed in a generalized linear model, with adjustment for vision and attention measures that might explain the UFOV score. Of the 1504 participants in this study, 10.1% did not attempt the mobility course. In a model adjusting for demographic, physical, cognitive and attention, and vision measures, a decrease of 50 ms in processing speed for the divided-attention task was associated with a 4.9% increase (P = 0.004) in number of bumps made over the course. Receiver operating characteristic curves were created for the UFOV and visual field tests, to determine accuracy in detecting those with a high number of bumps. The visual field test had slightly higher area under the curve, but positive predictive value for both tests was low. The UFOV test of divided attention, as measured by processing speed, independently predicted bumping while walking. These data suggest that poor visual attention is a significant risk factor for bumping while walking.