How can vision loss affect your brain?


Mmedical practice tends to divide its clients – you and me – into specialties defined by body parts: ophthalmology, neurology, gastroenterology, psychiatry, etc. But in fact, the human body does not function in silos. Rather, it works as an integrated whole, and what goes wrong in one part of the body can affect many others.

I have written about the potential damage hearing loss has on brain health, as well as the health of our bones, heart, and emotional well-being.

Untreated hearing loss can increase the risk of dementia. Even those with slightly less than perfect hearing can have measurable cognitive deficits.

Today, more and more research shows that vision loss can also affect brain function. As with hearing, if the brain has to work very hard to make sense of what our eyes are seeing, it can take a toll on cognitive function.

The latest study, published in JAMA network open in July, 1,202 people aged 60 to 94 followed for almost seven years on average. All were part of the Baltimore Longitudinal Study of Aging and underwent vision and cognition tests every one to four years between 2003 and 2019.

The researchers found that those who performed poorly on initial visual acuity tests – how well, for example, they could see the letters on an eye map at a given distance – were more likely to have cognitive decline at the same time. over time, including deficits in language, memory, attention and the ability to identify and locate objects in space.

Other vision problems, such as depth perception and the ability to see contrasts, have also had deleterious effects on cognitive abilities.

Principal investigator Bonnielin Swenor, epidemiologist and ophthalmologist at the Johns Hopkins Wilmer Eye Institute, said the new study “adds to growing longitudinal data showing that visual impairment can lead to cognitive decline in the elderly.”

Correcting poor vision is good for the brain

Lest you think the relationship is reversed – that cognitive decline impairs vision – another study Swenor worked on showed that when both functions were taken into account, visual impairment was twice as likely to occur. affect cognitive decline than the reverse. This study, published in 2018 in JAMA Ophthalmology and led by Diane Zheng of the Miller School of Medicine at the University of Miami, included 2,520 adults living in the community aged 65 to 84, whose vision and cognitive function were periodically tested. She and her co-authors concluded that maintaining good vision as they age may be an effective way to minimize the decline in cognitive function in the elderly.

When people have vision loss, they change the way they live

Diane zheng

“When people have vision loss, they change the way they live. They decrease their physical activity and they decrease their social activity, both of which are so important to maintaining a healthy brain, ”said Swenor. “It puts them on a fast track to cognitive decline.”

But identifying and correcting vision loss early on can help, Zheng said. She suggested regular eye exams – at least once every two years, and more often if you have diabetes, glaucoma, or other conditions that can damage vision. “Make sure you can see through your glasses,” she urged.

When glasses alone are not enough

There are “visual impairments that glasses don’t fix,” Swenor said, such as age-related macular degeneration and glaucoma. Retinal disease began to affect Swenor’s vision in his mid-twenties. Those with problems like hers can benefit from something called low vision rehabilitation, a kind of physical eye therapy that helps people with low vision adjust to common situations and helps them function better. in society.

Swenor, for example, can see objects in a high contrast situation, such as a black cat against a white fence, but has difficulty seeing the difference between similar colors. She can’t pour white milk into a white cup without spilling it, for example. His solution: use a dark colored mug. Finding such accommodation is a permanent task, but it allows him to continue to function well professionally and socially.

The company must also help the visually impaired to function safely outside the home. Most things in hospitals are white, for example, which creates safety risks for people with reduced contrast sensitivity. As a 50 year old driver, I have noticed that road barriers that were the same color as the road surface are now more often rendered in high contrast colors like orange or yellow, which reduces undoubtedly accidents even for people who can see perfectly.

“We need to create a more inclusive society that welcomes the visually impaired,” Swenor said.

Home Improvements May Support Brain Health

People with depth perception issues can also incorporate useful design features into the home. Placing colored bands on risers, varying furniture textures, and color-coding objects can all improve the ability to navigate safely. People who can no longer read books can also listen to audiobooks, podcasts or music instead, Swenor said.

The link between visual impairment and cognitive impairment “is not an apocalyptic message,” she added. “There are many ways to support brain health in people with vision loss. “

This article originally appeared in The New York Times.


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