Within the next few years, doctors may detect early signs of Alzheimer’s disease and other dementias during routine eye exams, long before symptoms appear. A new study published in Alzheimer’s & Dementia suggests that tiny changes in retinal blood vessels could serve as an early biomarker for brain health.
The Link Between Retina and Brain
Researchers at The Jackson Laboratory (JAX) found that mice carrying a common genetic mutation associated with Alzheimer’s risk showed abnormal changes in their retinal blood vessels. These findings build on the team’s earlier work, which revealed similar vascular changes in the brain and abnormalities in specific retinal cells tied to dementia risk.
“The retina is essentially an extension of the brain,” explained neuroscientist Alaina Reagan, who co-led the study with Professor Gareth Howell. “Because it is more accessible, doctors can use it to detect subtle changes in blood vessels that may reflect what is happening in the brain.”
Genetic Mutation and Retinal Changes
As reported by news-medical.net, the team studied mice with the mutation MTHFR677C>T, present in up to 40% of people. By six months of age, the mice showed twisted vessels, narrowed and swollen arteries, and fewer vessel branches in their retinas. These changes mirror vascular problems in the brain that reduce blood flow and increase dementia risk.
“We can see these wavy vessels in the retinas, which also appear in people with dementia,” Reagan said. “That points to a systemic issue, possibly linked to blood pressure, that affects both the brain and the retina.”
Confirming Earlier Findings
In 2022, the same group reported similar vascular changes in the brains of mice with the MTHFR677C>T mutation. The mice had fewer vessels in the cortex and reduced blood flow to the brain. The new study also revealed disruptions in energy production, protein clearance, and vessel support in both the brain and retina.
“These systems appear to work in tandem,” Reagan said. “The molecular changes suggest a close connection between retinal health and brain function.”
Impact of Age and Sex
The study also highlighted how age and sex influenced outcomes. Female mice showed more severe retinal changes, including reduced vessel density and branching by 12 months of age. This aligns with human data showing that women develop dementia more often than men, according to the World Health Organization.
Toward Clinical Applications
To test whether these retinal changes also occur in humans, the team is partnering with clinicians and dementia specialists at Northern Light Acadia Hospital in Maine. The goal is to integrate eye exams into dementia risk assessments and communicate early warning signs to patients.
“Most people over 50 already undergo annual vision checks,” Reagan noted. “If doctors spot vascular changes during these exams, it could signal increased dementia risk—perhaps 20 years before symptoms appear. That would provide a critical window for early interventions.”
A New Approach to Alzheimer’s Risk
The researchers emphasize that Alzheimer’s and other dementias result from multiple genetic and environmental factors. Still, understanding how retinal health reflects overall vascular health could help clinicians identify at-risk patients earlier and recommend preventive strategies.
“This work is not about finding a single cause or solution,” Reagan said. “It’s about recognizing the retina as a powerful tool to better understand—and potentially intervene in—neurodegenerative diseases.”