Researchers from Queen’s University Belfast, Northern Ireland, have shown for the first time that the eye could be a surrogate for brain degeneration such as Alzheimer’s disease (AD).
This research is the first clinical study to show a potential for peripheral retinal imaging to be used in monitoring Alzheimer’s disease and potentially other neurodegenerative diseases. It has shown for the first time how the eye could lead to a better understanding of brain degeneration.
The team, led by Dr Imre Lengyel, senior lecturer and researcher at the School of Medicine Dentistry and Biomedical Sciences at Queen’s University, have found that by examining the eye they could potentially be able to reflect on what may be taking place in the brain.
Exploring the eye for brain degeneration
The work was carried out alongside health professionals and care providers for Alzheimer’s patients, which explored whether there are manifestations of the degenerative disease in the eye.
The team hypothesised that changes in the peripheral retina could be important to explore the association between the eye and the brain.
Using ultra-wide field imaging technology, the team found that that there are indeed several changes that seem to be associated with this debilitating condition.
What observations were made?
One of the changes observed was a higher than normal appearance of drusen, the yellow ‘spots’ identifiable on retinal images in people with Alzheimer’s.
Drusen are small deposits of fat, proteins and minerals, including calcium and phosphate deposits, that form in a layer underneath the retina.
These spots are a symptom of ageing and often seen in people over 40. A few of these deposits are harmless, but once they increase in number and size they contribute to the degeneration of the retina.
Lengyel said: “These exciting research results suggests that our original hypothesis was right and wide field eye imaging could indeed help monitoring disease progression in patients with AD [Alzheimer’s disease].”
Another significant change was measured in the peripheral retinal blood circulation in Alzheimer’s disease. The researchers found that people with the degenerative disease have wider blood vessels close to the optic nerve, but these thin faster than in control subjects towards the retinal periphery. Both are likely to slow blood flow and impair nutrient and oxygen flow in the peripheral retina.
While peripheral retinal imaging is not a diagnostic measure for AD, the simple, quick and inexpensive monitoring of change in the eye could serve as a tool for disease progression in the brain.
Professor Craig Ritchie, Professor of the Psychiatry of Ageing at the University of Edinburgh, UK, and co-author of the study, said: “Changes in the eye are very easy to measure relative to other measures of brain health.
“Our research team, led by Queen’s University, was able to identify early markers in people many years before dementia develops. We have opened a window to identify high risk groups who may benefit from specific prevention advice.”