New Eye Scan Can Detect Signs of Alzheimer’s Disease

Eye exams may soon serve a larger purpose than detecting vision changes.

Because the retina is an extension of the brain and shares many similarities with the brain, researchers believe that the deterioration in the retina may mirror the changes going on in the blood vessels in the brain, thereby offering a window into the disease process.

Researchers from the Duke Eye Center have shown that a new, non-invasive imaging device called OCTA can see signs of Alzheimer’s disease in a matter of seconds. The researchers found that the small blood vessels in the retina at the back of the eye are altered in patients with Alzheimer’s. And they showed that they can distinguish between people with Alzheimer’s and those with only mild cognitive impairment. This latest research is the largest study to date and adds to the current literature as scientists strive to find a quick, noninvasive, and inexpensive way to detect Alzheimer’s at the earliest stages. Their study was published online in Ophthalmology Retina, a journal of the American Academy of Ophthalmologyby Sharon Fekrat, M.D. and Dilraj Grewal, M.D.

They compared the retinas in 70 eyes of 39 Alzheimer’s patients with 72 eyes of 37 people with mild cognitive impairment, as well as 254 eyes of 133 cognitively healthy people. They found that the Alzheimer’s group had loss of small retinal blood vessels at the back of the eye and that a specific layer of the retina was thinner when compared to people with mild cognitive impairment and healthy people. The differences in density were statistically significant after researchers controlled for factors including age and sex.

Diagnosing Alzheimer’s is a challenge. Some techniques can detect signs of the disease but are impractical for screening millions of people: Brain scans are expensive and spinal taps have risks. Instead, the disease is often diagnosed through memory tests or observing behavioral changes. By the time these changes are noticed, the disease is advanced. Even though there is currently no cure, early diagnosis will allow researchers to study new medications earlier as future treatments may be more effective when given early. Earlier diagnosis would also give patients and their families time to plan for the future.

SOURCE: AAO news release 3/11/19