Physical activity in people aged 50+ with low vision

Abstract

Purpose : The health benefits of physical activity are widely recognised. The aims of this study were to objectively measure physical activity in a population of community-dwelling people aged 50+ with low vision and to explore the relationship between physical activity and vision impairment.

Methods : Eligibility criteria were age 50+ years and registration with Guide Dogs NSW/ACT, a community-based organisation providing orientation and mobility training for people living in the community with vision impairment. Physical activity was measured for one week using a wrist-worn accelerometer (Actigraph wGT3X-BT). Participants underwent field-based assessments of vision including visual acuity (VA) using an electronic chart on a tablet, MARS Contrast Sensitivity (CS) test and confrontation visual fields (VF). Self-reported comorbidities were combined as the functional comorbidities index (FCI) and weight and height were used to calculate body mass index (BMI). Accelerometer data were processed with a low activity filter, suitable for populations with very slow shuffling movements. Average daily activity count and the proportion of time spent in sedentary, light and moderate-vigorous physical activity were calculated. The impact of vision impairment on activity count was modelled adjusting for age, FCI and BMI.

Results : The average age of study participants was 72±9 years, 43/80 (54%) were female and mean BMI was 28.0±5.2. Close to two-thirds (52/80, 65%) reported a fall in the past year. LogMAR VA was 1.39±1.10, CS 0.74±0.66 log units and 57/80 (71%) had a functional VF defect. Over one week, 58% (95% CI 55-60%) of time was spent as sedentary, 32% (95% CI 30-33%) in light physical activity and 11% (95% CI 9-12%) in moderate-vigorous activity. Age and BMI were the strongest predictors of total activity (adjusted R²=0.26) whereby there was 26% of one SD reduction in daily activity count per 5 years older and 5% of one SD reduction per unit increase in BMI. CS and VA were both predictive of activity but only marginally improved the fit of the model (R²=0.33).

Conclusions : This study confirmed low levels of activity in this population of older people with significant vision loss and a high rate of falls. Most of the day was spent as sedentary or doing light activity with only 11% of time spent in moderate-vigorous physical activity. These findings provide insights into activity levels in older people living in the community with vision impairment.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.