The researchers used a new imaging method (called optical coherence tomography angiography or OCTA) to look at minute blood vessels in the back of the eye. These blood vessels, which are located in the retina, are thinner than a single strand of human hair, yet they’re the key to distinguishing mild cognitive impairment from the serious neurological disease that is Alzheimer’s. How, you ask? According to the study, these tiny blood vessels become altered in patients with Alzheimer’s. So, when OCTA is used and experts are able to capture an image of the vessels, they’re able to distinguish regular “retinal microvascular” activity from the irregular. In other words, they’re able to accurately detect Alzheimer’s disease.
Throughout the study, researchers analyzed the eyes of 39 Alzheimer’s patients, as well as the eyes of 37 people with mild cognitive impairment and the eyes of 133 healthy people. They saw a loss in retinal blood vessels in the Alzheimer’s patients, as well as a thinning of a retinal layer. These two physical signs proved statistically significant for disease detection.
Now, we must say, tiny blood vessels in the retina don’t strike us as being critically correlated to brain health, but according to the researchers, the retina is essentially “an extension” of the brain. As such, its deterioration could reflect the brain’s potential deterioration, hinting at the destructive mechanisms of the disease.