New Vision Test May Spot Alzheimer’s Before Your Memory Slips

For years, a few brain researchers have been looking into a non-invasive method to diagnose Alzheimer’s disease before symptoms begin. They’re focused on the only part of the brain that’s visible without using complicated imaging techniques like X-rays or drilling open the skull. 

They’re looking at the retina, located at the back of the eye. The retina’s nerve tissue is, believe it or not, an extension of the brain. As you age, it undergoes significant changes that can reveal the health of your brain and whether your memory will remain strong or falter. Pretty much every Alzheimer’s disease researcher believes early detection of this type of memory-robbing dementia (or any type of dementia for that matter) is critical to create effective treatments. As Robert Vince, researcher at the Center for Drug Design at the University of Minnesota, explained, “First, effective treatments (for Alzheimer’s) need to be administered well before patients show actual neurological signs. Second, since there are no available early detection techniques, drugs currently cannot be tested to determine if they are effective against early Alzheimer's disease.” In other words, our best hope for staving off Alzheimer’s is to treat people before the disease causes widespread brain damage. But you can’t try out therapies for the early stages of the disease if you don’t know which people are in those early stages. Or – to be more accurate – you can’t try out conventional treatments like drugs. The effective natural treatments should be applied your whole life, because most of them are lifestyle changes we all need to do anyway. But knowing you’re starting to get dementia can be a great motivator to make those changes, so I’m all in favor of early detection. The fact is, by the time your intellectual abilities begin to deteriorate, it can be harder to stop your precious brain cells from going bad or disappearing altogether.

For Early Detection, Look Dementia in the Eye

Dr. Vince and others began investigating if changes in the retina hold reliable clues to what’s going on in the rest of your brain. One change is that the retina grows thinner over time. So, Dr. Vince began investigating whether a thinning retina might signify an early stage of Alzheimer’s. In his lab tests on animals Dr. Vince found that he could spot changes in the animals’ retinas before they developed cognitive problems.¹ And since then, while he and his colleagues have been doing research on human subjects, he says the technique of measuring the thickness of the retina is “promising” but he admits the technique is not yet ready for prime time.² Researchers at Duke now say they’ve found a solution to this dilemma. And they claim their discovery will one day allow doctors to spot early Alzheimer’s disease with an eye exam. According to these scientists, the trick is to also look at shifts in the texture of the retina’s surface.

Early Warnings Include Not Only Retinal Thickness, But Texture

"Previous research has seen a thinning of the retina in Alzheimer's patients, but by adding a light-scattering technique to the measurement, we've found that the retinal nerve fiber layer is also rougher and more disordered," says researcher Adam Wax, who teaches biomedical engineering at Duke. "Our hope is that we can use this insight to create an easy and cheap screening device that wouldn't only be available at your doctor's office, but at places like your local pharmacy as well." Dr. Wax says his lab tests on animals demonstrate that the top layer of neurons that cover the retina get sloppier and disrupted, shifting their structural texture as Alzheimer’s begins in its very early stages.³ He adds that if you measure retinal thinning with one device and then correlate those measurements with the disorderly texture characteristics revealed by another tool – voila! You can get a good idea of whether or not somebody is developing Alzheimer’s. Dr. Wax insists that these combined measurement techniques could someday be incorporated into a relatively cheap device that doctors can use in their offices.

Don’t Forget About Your Pupils!

And he’s not the only Alzheimer’s researcher developing a vision testing technique to diagnose early Alzheimer’s. There is another test in the works that measures pupil dilation. Researchers at the University of California San Diego recently found that the more pupils widen when taking a cognitive test, the more a person struggles to perform well. When researchers tested people with mild cognitive impairment or those at higher genetic risk for Alzheimer’s disease, they found their pupils widened more quickly and to a larger size than did those of the control group. The idea, these researchers say, is that measuring pupil dilation could one day allow doctors to diagnose early Alzheimer’s disease. Meanwhile, sleeping well, eating right and exercising -- along with taking supportive nutritional supplements -- are your best insurance for lowering your Alzheimer’s risk.

How can the retina indicate early Alzheimer’s?

The retina, an extension of the brain, shows thinning and texture changes as Alzheimer’s begins.

What role does pupil dilation play in Alzheimer’s detection?

Research shows that larger and faster pupil dilation during cognitive tests may signal early cognitive decline.

Can these eye tests replace traditional Alzheimer’s diagnostics?

While promising, these methods are still under development and not yet ready for widespread clinical use.

Why is early detection of Alzheimer’s important?

Early detection allows for timely interventions, including lifestyle changes and emerging treatments, before significant brain damage occurs.

What lifestyle habits can reduce Alzheimer’s risk?

Regular exercise, quality sleep, a healthy diet, and nutritional supplements can help lower your risk.
 

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1. More SS, Beach JM, Vince R. Early Detection of Amyloidopathy in Alzheimer's Mice by Hyperspectral Endoscopy. Invest Ophthalmol Vis Sci. 2016 Jun 1;57(7):3231-8. doi: 10.1167/iovs.15-17406. PMID: 27333181. https://pubmed.ncbi.nlm.nih.gov/27333181/
2. More SS, Beach JM, McClelland C, Mokhtarzadeh A, Vince R. In Vivo Assessment of Retinal Biomarkers by Hyperspectral Imaging: Early Detection of Alzheimer's Disease. ACS Chem Neurosci. 2019 Nov 20;10(11):4492-4501. doi: 10.1021/acschemneuro.9b00331. Epub 2019 Oct 24. PMID: 31603648.https://pubmed.ncbi.nlm.nih.gov/31603648/
3. Song G, Steelman ZA, Finkelstein S, Yang Z, Martin L, Chu KK, Farsiu S, Arshavsky VY, Wax A. Multimodal Coherent Imaging of Retinal Biomarkers of Alzheimer's Disease in a Mouse Model. Sci Rep. 2020 May 13;10(1):7912. doi: 10.1038/s41598-020-64827-2. PMID: 32404941; PMCID: PMC7220911. https://pubmed.ncbi.nlm.nih.gov/32404941/