Purpose:
Vision deteriorates as we age. Impaired vision may result in substantial adverse effects in balance functions, predisposing older people to falls. Since falls seldom occur during double-leg stance, evaluation of balance control is important to confine to both double-leg and single-leg stance. This study examined the relationship between visual factors and postural stability measured at different compliant conditions among community-dwelling older adults in Hong Kong.
Methods:
128 community-dwelling aged 60 to 95 years were recruited from community-dwelling centres using convenience sampling (75.6 ± 7.1 years). Demographic information and history of falls in the previous 3-month were collected. Fear of falling was measured by Activity-related fear of falling using the Activities-Specific Balance Confidence Scale (ABC). Participants’ habitual distance and near visual acuity (better eye), contrast sensitivity and stereoacuity were measured by Lea Numbers chart, Melbourne Edge Test and Randot Stereotest respectively. Balance function in terms of postural sway was measured by a swaymeter for a maximum of 15 sec for each condition: 1) stood on firm and compliant foam surfaces; and 2) double-leg and single-leg stance on dominant leg. Area of the displacements of the body at the level of waist for each condition were recorded and computed in terms of log millimeter square per second.
Results:
Postural stability was significantly deteriorated while standing on a foam surface and on single-leg stance than on a firm surface with double or single-leg stance (p<0.01). Significant age-related declines were found in the postural sway (standing on foam surface with double-leg stance) and vision measures (distance and near acuities, contrast sensitivity, p0.05). One possible reason for this finding might be attributed to the healthier and active participants recruited in this sample. Demographic summary revealed a lower incidence of falls (8.6% participants reported falls in the past 3-month), higher frequency of regular exercise (82% participants reported having exercise at least 3 times per week), and high self-perceived balance confidence in ABC Scale (mean Balance confidence of 71.2).
Conclusions:
Vision and postural stability deteriorated due to aging. However the deterioration rate for vision and postural stability could be different, depending on the personal health and engagement in exercise.
Keywords: aging: visual performance • clinical (human) or epidemiologic studies: risk factor assessment