Scientists found the retina was thinner in people with Alzheimer's and they had also lost more small blood vessels at the back of the eye, compared to healthy people and those with mild cognitive impairment, a forerunner to dementia. The primary aim for researchers was to spot retinal degeneration that may be particularly linked to Alzheimer's disease. The test involves looking at blood vessels in the retina, but isn't something that now takes place as part of a normal eye test. More than 500,000 people in Britain suffer from Alzheimer's and the total is rising, but most are diagnosed too late to do anything about it. Changes in blood vessels density in the retina may indicate similar activity within the brain which occurs with the disease; these changes may even occur before symptoms become noticeable which is why this eye scan could be groundbreaking. The differences in density were statistically significant after researchers controlled for factors including age and sex.
For their study, researchers used OCTA to compare 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. 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. By the time these changes are noticed, the disease is advanced.
This correlation could mean big things for the future of Alzheimer's diagnoses.
Ophthalmologist and senior author Sharon Fekrat, M.D., Professor of Ophthalmology at Duke, along with lead author Dilraj Grewal, M.D., Associate Professor of Ophthalmology at Duke, expect that their work may one day have a positive impact on patients' lives.
With almost 6 million Americans living with Alzheimer's disease and no viable treatments or noninvasive tools for early diagnosis, its burden on families and the economy is heavy. If we can detect these blood vessel changes in the retina before any changes in cognition, that would be a game changer'. Some of the changes detected were in capillaries or blood vessels that measured less than the width of a human hair he explained.