Abstract
Abstract: :
Purpose: To evaluate changes in vision function longitudinally in a population of elders and to compare our previous cross-sectional results to the longitudinal findings. Methods: A battery of vision function tests was administered twice to a population of 598 older observers. Their ages were 73.8 years (sd 8.5) and 78.2 years (sd 8.0) respectively. The test battery included measures of acuity under conditions of high and low contrast, reduced luminance and disability glare, contrast sensitivity, glare recovery, visual fields with and without attentional components, stereopsis, color and temporal vision and reading performance. Testing was done binocularly with habitual correction. Results: The participants were divided into 3 groups based on age at the 1st visit: young-old (<70 yrs), old (70-79 yrs), and old-old (80 yrs and over). Changes in spatial vision measures were calculated as log units/decade to facilitate comparison between individuals with different inter-test intervals. High and low contrast acuity showed small declines of 4-6 letters/decade (0.10 log unit/decade) in the two younger age groups and 9 letters/decade (0.18 log units/decade) in those over 80 years. Contrast sensitivity loss of about 5 letters/decade (0.25 log units) was found for each age group. Acuity in the presence of glare declined about 10 letters/decade (0.20 log units/decade). A dramatic progressive loss was found for low contrast, low luminance acuity (SKILL dark acuity) which declined by 11.5, 25.5 and 45 letters/decade (0.23, 0.51, 0.90 log units/decade) for the 3 age groups. Stereopsis and glare recovery also showed an exponential increase in the rate of change. Attentional visual field diameter shrunk in the oldest age group by 49 degrees/decade while the old group lost 18 deg/decade and the young-old showed minimal change. Cross-sectional and longitudinal results were similar for high/low contrast acuity, contrast sensitivity and acuity in glare, stereopsis and attentional visual fields while increasingly severe rates of decline were seen in the longitudinal data for low contrast low luminance acuity, and glare recovery. Conclusion: The rate of decline in vision functions varies dramatically with age across different measures. Though similar for some vision functions, longitudinal measures in the same population show more rapid declines than expected from cross-sectional data for other vision measures. This result is contrary to expectations from cohort effects and selection bias which would predict relatively better function in the longitudinal data set.
Keywords: 309 aging • 310 aging: visual performance • 620 visual acuity