‘Game changer’: Simple eye scan may detect Alzheimer’s earlier, study finds

DURHAM, N. C. — Your eyes may be the window to your soul, but thanks to new research, they may also be the key to detecting Alzheimer’s disease early on. Researchers at the Duke Eye Center say a simple eye scan may reveal activity in the brain associated with the debilitating condition.

Eye doctors may not only be fitting patients with glasses or contacts in the future, but they could also be routinely checking people for Alzheimer’s. The research team found that blood vessel activity in the eyes of Alzheimer’s patients is notably different from that within healthy individuals.

On the left, the retina of a healthy person shows a dense web of blood vessels, the highest-density areas highlighted in red and orange. On the right, the retina of a person with Alzheimer’s disease shows areas in blue and teal where blood vessels are least dense. The images were captured using optical coherence tomography angiography (OCTA).

“We know that there are changes that occur in the brain in the small blood vessels in people with Alzheimer’s disease, and because the retina is an extension of the brain, we wanted to investigate whether these changes could be detected in the retina using a new technology that is less invasive and easy to obtain,” says lead author Dr. Dilraj S. Grewal, M.D., an ophthalmologist and retinal surgeon at Duke, in a media release.

In healthy people, blood vessels form a dense web inside the retina, researchers say, but in patients with Alzheimer’s, that web is notably weaker. Using a noninvasive technology called optical coherence tomography angiography (OCTA), the authors were able to spot these differences when looking at the eyes of 133 healthy people, compared to 39 people with Alzheimer’s and 37 people with mild cognitive impairment. The OCTA eye scan allows doctors to take high-resolution images of the retina in just a few minutes and see blood vessel activity.

Changes in the blood vessel density in the retina could indicate similar activity within the brain that occurs in people with Alzheimer’s. But these changes may occur before symptoms become noticeable, such as changes in memory. That’s why the authors believe this eye scan could be groundbreaking.

“Early diagnosis of Alzheimer’s disease is a huge unmet need,” says senior author Dr. Sharon Fekrat, an ophthalmologist and retinal surgeon at Duke, in a statement to the American Academy of Ophthalmology. “It’s not possible for current techniques like a brain scan or lumbar puncture (spinal tap) to screen the number of patients with this disease. It is possible that these changes in blood vessel density in the retina may mirror what’s going on in the tiny blood vessels in the brain. Our work is not done. If we can detect these blood vessel changes in the retina before any changes in cognition, that would be a game changer.”

The study was published in the journal Ophthalmology Retina.