A new study lends weight to the idea that vision problems and dementia are linked.
In a sample of nearly 3,000 older adults who took vision tests and cognitive tests during home visits, the risk of dementia was much higher among those with eyesight problems.
All of the older adults in the study were over the age of 71, with an average age of 77. They had their up-close and distant vision, and their ability to see letters that didn’t contrast strongly with their background, tested by a visiting team member using a digital tablet. They also took tests of memory and thinking ability, and provided health information including any existing diagnosis of Alzheimer’s disease or another form of dementia.
Just over 12% of the whole group had dementia. But that percentage was higher — nearly 22% — among those who had impaired vision for seeing up close.
In addition, one-third (33%) of those with moderate or severe distance vision impairment, including those who were blind, had signs of dementia. So did 26% of those who had trouble seeing letters that didn’t contrast strongly against a background.
Even among those with a mild distance vision issue, 19% had dementia.
After the researchers adjusted for other differences in health status and personal characteristics, people with moderate to severe distance vision issues were 72% more likely than those with no vision issues to have dementia.
The gaps were smaller, but still large, for other types of vision impairment — except mild problems with distance vision, where there was no statistical difference.
Those who had more than one kind of vision impairment were also 35% more likely to have dementia than those with normal vision.
The authors, led by ophthalmologists Olivia Killeen, M.D., M.S. and Joshua Ehrlich, M.D., M.P.H., write, “Prioritizing vision health may be key to optimizing both sight and overall health and well-being. Randomized trials are warranted to determine whether optimizing vision is a viable strategy to slow cognitive decline and reduce dementia risk.”
But in the meantime, in an accompanying editorial, Sheila West, Ph.D., of the Wilmer Eye Institute at Johns Hopkins Medicine, wrote that the new study adds to accumulating evidence about the link between vision and cognitive issues.
“Equitable access to vision care services that prevent, reverse, or at least stave off progression of loss of sight is a worthy goal regardless of the potential impact on dementia and may be especially critical for those experiencing cognitive decline,” she wrote.
Olivia J. Killeen, Yunshu Zhou, Joshua R. Ehrlich. Objectively Measured Visual Impairment and Dementia Prevalence in Older Adults in the US. JAMA Ophthalmology, 2023; DOI: 10.1001/jamaophthalmol.2023.2854
Photo by Georg Arthur Pflueger