New Zealand research has discovered a link between eye health and dementia.
The University of Otago – Ōtākou Whakaihu Waka study discovered retinal microvasculature can show early signs someone is at risk of developing dementia.
Co-lead author Dr Ashleigh Barrett-Young, of the Department of Psychology, said the findings link to previous work by members of the research team, “putting together pieces of a puzzle” when it comes to recognising early signs of dementia.
The findings are too premature to be applied in the real world yet, but research is continuing around the world.
“Treatments for Alzheimer’s and some other forms of dementia may be most effective if they’re started early in the disease course,” Dr Barrett-Young said.
Knowing who would benefit from early treatment is crucial, but difficult to do with current testing methods, which she hopes will improve in the future.
Cognitive tests aren’t sensitive enough in the early stages and a person may not be experiencing any decline yet, while other tests, like magnetic resonance imaging (MRI) and positron emission tomography (PET) scanning, are expensive and not widely available.
“In our study, we looked at the retina which is directly connected to the brain,” she said.
“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 to identify people at risk of developing dementia.”
I was surprised that venules were associated with so many different domains of Alzheimer’s disease – that suggests that it might be a particularly useful target for assessing dementia risk.
Unexpected Finding
Published in the Journal of Alzheimer’s Disease, researchers used data from eye scans from the Dunedin Study’s age 45 assessment. It is New Zealand’s longest-running longitudinal study and is considered the world’s most detailed study of human health and development.
The scans reveal narrower arterioles (the small blood vessels that carry blood away from the heart) and wider venules (the smallest veins which receive blood from capillaries), and thinner retinal nerve fibre layers (which carry visual signals from the retina to the brain) were associated with greater dementia risk.
Dr Barrett-Young said the finding was somewhat unexpected.
“I was surprised that venules were associated with so many different domains of Alzheimer’s disease – that suggests that it might be a particularly useful target for assessing dementia risk.”
Reference
- Barrett-Young A, Reuben A, Moffitt T, et al. Measures of retinal health successfully capture risk for Alzheimer’s disease and related dementias at midlife. J Alzheimers Dis. 2025 Mar 3:13872877251321114. doi: 10.1177/13872877251321114. Epub ahead of print.
