Vision loss strongly associated with declining cognition, study shows
Age-related loss of vision leads to decline of cognitive function, according to a study involving 2c520 adults 65 to 85 years old and living in the greater Salisbury area in Maryland.
At baseline, visual acuity was measured with ETDRS charts and cognitive status by the Mini-Mental State Examination (MMSE) questionnaire, testing 11 tasks related to orientation to time and space, registration, and recall of words, attention, calculation, language and visual construction. For low vision patients, the items requiring sight were omitted. Reassessment was scheduled at 2, 6 and 8 years. Over time, 50% of the participants were lost to follow-up due to death.
At baseline, mean visual acuity was 20/25, and mean cognitive functioning was within the normal range. Worse baseline visual acuity was significantly associated with worse baseline MMSE. Over time, both vision and MMSE score declined. The mean loss of vision was one letter, and the number of participants with cognitive impairment increased from 11% at baseline to 20.6% at 8 years. The rate of visual acuity loss was associated with the rate of declining MMSE score.
Comparing the effect of visual acuity at baseline on cognitive function at 2 years vs. the reverse, the authors found that the standardized regression coefficient of visual acuity to MMSE score was almost twice that of MMSE score to visual acuity (0.074 vs. 0.038, both P < .001).
“This demonstrated visual acuity is likely the dominating factor of the dynamic associations between visual acuity and MMSE score. To our knowledge, this is the first time this dependency has been shown,” they wrote.
These findings also support the hypothesis that visual impairment might affect cognitive function because it reduces the ability of older adults to participate in brain-stimulating activities and suggest that maintaining good vision is important for cognitive health.
“Worsening vision in older adults may be adversely associated with future cognitive functioning. The study finding suggests maintaining good vision through the prevention and treatment of vision disorders in old persons may be a strategy to lessen age-related cognitive changes,” lead author D. Diane Zheng, MS, told Primary Care Optometry News. – by Michela Cimberle
Disclosure: Zheng reported no relevant financial disclosures. Please see the study for the other authors’ financial disclosures.