The surprising sign in your eyes that indicates if you’ll get dementia later in life
Memory loss is the tell-tale sign that you or a loved one could be developing dementia.
However, emerging science shows your eyes could hold the first signs of the devastating disease years before diagnosis.
Now, scientists have pointed toward the retina as a potential indicator. The retina is the light-sensitive tissue that lines the back of the eye and captures images. It then takes those images and converts them into signals for the brain, creating vision.
In a study published earlier this year, researchers in China found the thickness of the retina could help predict Alzheimer’s disease, the most common form of memory-robbing dementia.
After following about 30,000 adults for nearly a decade, the team found people with a thinner retina were at a greater risk of developing Alzheimer’s disease within the study period.
And in the same study, thinner layers covering the macula, the central part of the retina, were associated with up to a 41 percent greater risk of being diagnosed with Alzheimer’s disease.
This recent research builds on past studies that have tied the eyes to dementia.
A separate 2022 study showed that having a thicker layer around the macula was associated with better cognitive scores, and people with the thinnest macula saw the greatest decline in scores. And participants with a thinner macula were also more likely to be diagnosed with Alzheimer’s disease after the five-year follow-up.
Changes in the eye’s retina could predict Alzheimer’s disease risk, recent studies show (stock image)
Experts believe the retina may predict Alzheimer’s risk because it is part of the central nervous system and is connected directly to the brain via the optic nerve.
This makes the eye vulnerable to degeneration in the brain caused by Alzheimer’s disease, including nerve cell loss, inflammation and vascular damage.
Retinal thinning can also be a sign of brain changes like reduced brain volume and atrophy.
People with retinal thinning most often do not have symptoms at first, but as the condition progresses, it may lead to blurred vision, spots in vision, trouble seeing in dim light, reduced color or peripheral vision or a curtain-like shadow in the eyesight.
It’s most often caused by aging, eye conditions like myopia (nearsightedness) and chronic conditions such as high blood pressure and diabetes.
Exact estimates vary, but experts suspect up to one in 10 Americans may have retinal thinning.
The findings on retinal thinning come as Alzheimer’s disease strikes nearly 7million Americans, with that figure set to nearly double by 2050.
In the recent study from China, published in the journal Frontiers in Aging Neuroscience, researchers looked at 30,000 adults who had not been diagnosed with dementia and were 55 years old on average.
After an average follow-up time of nine years, 148 were diagnosed with Alzheimer’s while eight were struck by frontotemporal dementia (FTD), a form of the dementia that often strikes earlier and causes drastic personality changes, language difficulties and movement issues.
Participants underwent retinal optical coherence tomography (OCT) imaging, a non-invasive test which uses light waves to take images of the eye. The test is largely used in routine eye exams for adults over 40.
The team found that for each unit of decrease in retinal thickness, the risk of developing Alzheimer’s disease increased by three percent, even after adjusting for risk factors such as age, sex, genetics and education.
Rebecca Luna’s (pictured here) early-onset Alzheimer’s symptoms appeared in her late 40s. She would black out mid-conversation, lose her keys and leave the stove before returning to find her kitchen full of smoke
Jana Nelson was 50 when diagnosed with early onset dementia, following severe personality changes and a sharp cognitive decline that left her unable to solve simple math problems or name colors
Thinning of the macula was also associated with a 41 percent increased risk of FTD, though the team noted more research is needed because only eight participants developed FTD.
In a separate study from South Korea, researchers looked at 430 adults with an average age of 76 who underwent OCT testing.
After five years, the team found people with a thicker macula lining had higher cognitive scores, and there was a greater decline in scores among those with thinner macula linings.
To prevent retinal thinning, eye experts recommend focusing on a diet filled with nutrients such as omega-3s, which prevent inflammation and other brain damage linked to dementia, and exercising regularly.
