Eye Health May Serve as Early Indicator of Dementia Risk, Otago Study Finds

A new study from the University of Otago—Ōtākou Whakaihu Waka has uncovered a significant link between eye health and the risk of developing dementia, suggesting the eye could be a window into early neurodegenerative changes.

Retinal Microvasculature Reflects Early Dementia Markers

Researchers from the Dunedin Multidisciplinary Health and Development Study have found that changes in the retinal microvasculature—the small blood vessels at the back of the eye—may signal early warning signs of dementia. These eye-based biomarkers could play a key role in identifying individuals at risk well before clinical symptoms appear.

Dr. Ashleigh Barrett-Young, co-lead author from the Department of Psychology at Otago, explained that the new findings build upon earlier research from the same team, gradually "putting together pieces of a puzzle" regarding the early detection of dementia.

“In our study, we looked at the retina, which is directly connected to the brain. It’s thought that many of the disease processes in Alzheimer’s are reflected in the retina, making it a good target as a biomarker,” she noted.

A Cost-Effective Alternative to Traditional Diagnostics

Current dementia screening methods—such as cognitive tests, MRI, and PET scans—are often limited by sensitivity, cost, or availability. In contrast, retinal imaging could offer a non-invasive, more accessible solution.

“Treatments for Alzheimer’s and some other forms of dementia may be most effective if they’re started early in the disease course,” said Dr. Barrett-Young. “Knowing who would benefit from early treatment is crucial, but difficult with current tools.”

Dunedin Study Reveals Key Retinal Changes

The study, co-led by Dr. Aaron Reuben of the University of Virginia, utilized eye scan data collected during the age 45 assessment of participants in the Dunedin Study—New Zealand’s longest-running and globally recognized longitudinal research program on human health and development.

Key retinal features associated with greater dementia risk included:

       • Narrower arterioles, which carry blood from the heart

       • Wider venules, the smallest veins receiving blood from capillaries

       • Thinner retinal nerve fiber layers, responsible for transmitting visual signals from the retina to the brain

These changes were linked with various domains of Alzheimer’s disease, with venule width emerging as an especially notable indicator.

“I was surprised that venules were associated with so many different domains of Alzheimer’s disease—that suggests it might be a particularly useful target for assessing dementia risk,” said Dr. Barrett-Young.

Eye Scans and the Future of Brain Health Monitoring

While the findings are promising, researchers caution that the work is still in its early stages. Current retinal imaging cannot yet predict an individual’s risk with certainty.

“This research is still in an early stage, and we can’t predict your future looking at an eye scan,” Barrett-Young emphasized. “Hopefully, one day we’ll be able to use AI methods on eye scans to give you an indication of your brain health, but we’re not there yet.”

The study was published in the Journal of Alzheimer’s Disease and represents an important step toward early, accessible biomarkers for neurodegenerative disease—potentially transforming how ophthalmology and neurology intersect in the future of preventive care.

Reference:

Ashleigh Barrett-Young et al, Measures of retinal health successfully capture risk for Alzheimer's disease and related dementias at midlife, Journal of Alzheimer's Disease (2025). DOI: 10.1177/13872877251321114