Abstract
Abstract: :
Purpose: To determine the association of reading speed and a measure of mobility performance with changes in visual function over a 6-year follow-up period in a population-based sample of older adults. Methods: Vision and performance data were obtained for a population-based sample of 1505 persons who had been enrolled in the original SEE study between 1993 and 1995 and were retested approximately 6 years later. Participants were between the ages of 72-92 at follow-up. Visual function was assessed with measures of binocular presenting ETDRS acuity, Pelli-Robson contrast sensitivity, Randot stereoacuity, and Humphrey 81-point visual fields. Reading speed was measured for newsprint-sized text and mobility was estimated from the time to ascend and descend a flight of stairs (stair speed). The association between task performance and visual function was analyzed using spline regression that simultaneously modeled cross-sectional and longitudinal effects. Models were adjusted for age, gender, race, education level, cognitive status, depression score, and number of comorbidities at the time of enrollment. Results: Reduced visual acuity was associated with a decline in reading speed. For example, the average reading speed for participants who lost three lines of visual acuity (20/20 to 20/40) was 21 words/minute slower than for participants whose acuity remained constant (20/20). Loss of contrast sensitivity was also independently associated with a decline in reading speed. Visual field loss was associated with a modest but statistically significant decline in stair speed. Compared to participants whose visual fields remained constant at 16 points missed, the average time to descend the flight of stairs was 7.9 sec longer for participants who missed 16 points at enrollment and 32 points at follow-up. None of the other vision variables were independently associated with stair speed, once visual fields were taken into account. Conclusion: Longitudinal changes in visual acuity and contrast sensitivity are associated with changes in reading speed for newsprint-sized text. Visual field was associated with a decline in mobility performance estimated from stair climb speed. These data show that multiple measures of visual function are associated with longitudinal changes in performance over a 6-year follow-up period.
Keywords: 310 aging: visual performance • 536 quality of life • 459 low vision