Moderate Impairment in Binocular Contrast Sensitivity Predicts Faster Mobility Decline in Cognitively Unimpaired...

Impaired contrast sensitivity (CS) commonly occurs in older adults but has been largely overlooked as a contributing factor to functional impairment and decline. We examined if CS impairment predicts decline in performance on the expanded short physical performance battery (eSPPB) over 30 months of follow-up in cognitively healthy older adults.

Single center prospective cohort study of 192 cognitively unimpaired older adults with good visual acuity and self-reported visual function. Linear mixed models examined the difference in the association of moderately impaired baseline CS (logCS < 1.55) with performance on the eSPPB and its components-balance, 4 m gait speed, narrow walk, and chair pace-over 30 months. Multivariable models adjusted for the effect of age, race, and sex on the slopes over time.

At baseline, the mean participant age was 76.5 ± 4.7 years, with 56.5% (N = 108) female and 9.4% (N = 18) black. Participants with moderately impaired CS at baseline had a significantly faster decline in eSPPB over a 30-month period (Beta: -0.115, 95% CI (-0.180, -0.050), p < 0.001) compared with those with normal CS (Beta: -0.022, 95% CI (-0.044, -0.001), p = 0.042). There was a difference in slopes of -0.093 units/year ((95% CI, -0.161, -0.024), p = 0.009) between groups. This difference in slopes remained significant after adjusting for the effect of age, sex, and race (difference in slopes -0.086, 95% CI (-0.155, -0.016), p = 0.016). Impaired CS predicted significantly greater declines in balance over 30 months (difference in slopes -3.512 (-6.826, -0.199), p = 0.0378), but the differences in gait speed, narrow walk, and chair pace were not significant.

In cognitively intact older adults with good visual acuity, moderately impaired CS was associated with a significantly faster decline in eSPPB, especially balance, over 30 months of follow-up. A relatively simple test of vision may identify a subset of older adults without cognitive dysfunction who are at risk for mobility decline.