Assessment
Correcting Vision Loss May Lower Dementia Risk
Recent research shows that treating common eye problems may help protect brain health
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Spotting and treating common eye problems is important to lowering the risk of dementia, according to recent studies.
The research is so convincing that in 2024 the Lancet Commission added vision impairment to its list of potentially modifiable risk factors for dementia. Unlike genetic factors, these risks — which also include high blood pressure, smoking and alcohol consumption — can be addressed with medical treatment or lifestyle changes.
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“Considerable new evidence has emerged,” noted the commission’s 2024 update. “A clear opportunity for dementia prevention exists with treatment of visual loss.”
Eye problems may signal later brain changes
The Lancet Commission report cites large studies that associate vision loss with dementia. They also show that vision loss typically precedes cognitive changes. Not all vision problems have been linked to dementia. But cataracts and diabetic retinopathy have been linked in observational studies to a higher risk, the report states.
Researchers also haven’t yet directly studied whether treating eye conditions reduces the risk of dementia, says ophthalmologist and researcher Dr. Josh Ehrlich, co-director of the Kellogg Eye Center for International Opthalmology at the University of Michigan.
He points to strong evidence that supports the commission’s recommendation: Older adults who had cataract-removal surgery were 30 percent less likely to develop dementia compared with those who did not undergo surgery, as a team of researchers in Seattle reported in JAMA Internal Medicine in 2021.
Plus, a study Ehrlich and other University of Michigan researchers published in JAMA Neurology in 2022 found that 1.8 percent of dementia cases may be attributable to vision loss. That may not sound like a lot, but that could amount to many thousands of people among the more than 6 million Americans who are currently living with dementia.
It’s also important to keep in mind, says Ehrlich, that vision impairment is among the most treatable dementia risk factors (easier than factors like air pollution, childhood education, and health conditions like obesity). “Eighty percent of vision loss globally is preventable or treatable,” he says.
The potential connection between eye and brain health
As with hearing loss, which the Lancet Commission added to its modifiable risk factor list in 2017, there are several hypotheses about how vision problems may affect brain health.
“The eye is an extension of the brain. It’s neural tissue,” Ehrlich says. First, it’s possible that the same disease process that leads to brain degeneration also harms vision. Changes in retinal thickness and structure have been linked to early Alzheimer’s disease, as well as Parkinson’s. In some research, these eye changes appear years before traditional dementia symptoms emerge.
Other hypotheses relate to a domino effect vision loss may have on the brain. As sight declines, the brain gets less sensory information. Resulting structural changes might lead to disease.
Losing sight may also change a person’s habits in a way that increases their risk for dementia, Ehrlich notes. Someone who can’t see well may stop going for daily walks, drop out of her book group or cribbage game, or become depressed. Research shows that while exercise, social connection and cognitive stimulation can help protect the brain, physical inactivity, social isolation and depression are independent risk factors for dementia.
“I don’t think there’s one pathway that applies to everyone,” says Ehrlich, and multiple pathways may be at work in each person. More important, “it’s not clear that the cause matters,” he says. The crux of the findings is that maintaining good vision appears to be important for maintaining good brain health.
What you can do now to keep your vision healthy
As research evolves on the link between eye and brain health, keep in mind that vision impairment is one dementia risk factor that’s straightforward to address.
Here’s how to keep your vision healthy: Get regular eye exams, both for glasses prescriptions and to identify treatable eye conditions that may have broader health implications. Prevent or manage conditions that affect both eye and brain health, such as diabetes and high blood pressure. (Following the six pillars of brain health will help build healthy habits.)
It’s a common misperception that losing sight is a normal part of aging, says Ehrlich. “But it’s not normal to not be able to see well,” he says. For those experiencing vision changes, early treatment and support can help maintain not just sight, but engagement with the world — and potentially brain health.
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