Eye doctors can now routinely check for Alzheimer's on their patients in the future as a research team at Duke Eye Center found that blood vessel activity in the eyes of patients with Alzheimer's is different from those without Alzheimer's.
"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.
Researchers stated that in healthy people, the blood vessels form a dense web inside their retina, but in patients with Alzheimer's, the web inside their retina is weaker. Using a noninvasive technology called OCTA or optical coherence tomography angiography, the researchers were able to see these differences when looking at the eyes of 133 healthy people compared to 39 patients with Alzheimer's and 37 people with mild cognitive impairment.
The OCTA eye scan gives doctors the ability to take high-resolution images of the retina of their patients in just a few minutes and see the blood vessel activity.
The changes in the blood vessel density found in the retina could mean a similar activity within the brain that occurs in those with Alzheimer's. But these types of changes may happen before the symptoms become noticeable, such as changes in memory. That is why the researchers believe that the eye scan could be groundbreaking in the world of medicine.
"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."
Diagnosing Alzheimer's is difficult, although there are techniques that can help detect the signs, they are not practical for screening millions of people. Brain scans are expensive and spinal taps have risks. This disease is usually diagnosed through memory tests or observing a patient's change of behavior but by the time that these changes are noticed, the disease has advanced. There is no cure for Alzheimer's currently, but being able to diagnose is early can mean that we are one step closer.
