The Influence of Visual Impairment on Cognitive Function
JAMA Ophthalmology, September 2018
Worsening vision and declining cognitive function are common among the elderly. To better understand the relationship between the 2 conditions, Zheng et al. conducted a population-based study of older U.S. adults and found that visual impairment might have a substantially large influence on declining mental abilities.
For this study, the researchers evaluated 2,520 adults aged 65 to 84 in 4 rounds across a 4-year period. Outcome measures included visual acuity (VA) via Early Treatment Diabetic Retinopathy Study (ETDRS) charts and cognitive status via the Mini-Mental State Examination (MMSE).
Both VA and MMSE scores worsened over time. The average biannual decline of VA was 0.022 logMAR, and the average annual decline in VA was 0.011 logMAR—an annual loss of less than 1 letter on the ETDRS acuity chart, or roughly 1 line over 8 years. For the MMSE score, the average biannual decline was −0.59.
The researchers also looked at the VA and MMSE relationship longitudinally and found that the rate of worsening VA was associated with the rate of declining MMSE score: For example, VA in the previous rounds of examination were associated with MMSE scores in subsequent rounds, and vice versa. However, the impact of VA on the MMSE scores was larger and stronger than the reverse, demonstrating that vision is likely the driving force in this dynamic relationship.
This longitudinal association between vision and cognitive function suggests that maintaining good vision could be an important strategy for minimizing age-related cognitive change. (Also see related commentary by Paul J. Foster, PhD, FRCS (Ed), Sharon Y.L. Chua, PhD, and Axel Petzold, MD, PhD, in the same issue.)
The original article can be found here.