Could the key to detecting Alzheimer’s disease lie in a simple eye exam? According to new research, the answer may be yes. A recent study published in Alzheimer’s & Dementia suggests that routine retinal scans could one day help identify early signs of Alzheimer’s and other dementias, potentially decades before symptoms appear. The findings, from a team at The Jackson Laboratory (JAX), offer compelling evidence that the eye may serve as a window into brain health.
The study focused on a genetic mutation known as MTHFR677C>T, which is found in up to 40% of people and is associated with increased risk for Alzheimer’s disease. Researchers observed that mice with this mutation showed abnormal changes in the blood vessels of their retinas—specifically, twisted and irregular vessels, narrowed arteries, and reduced branching. These changes were evident as early as six months of age in the mice, long before any cognitive symptoms would be expected.
“If you’re at an optometrist or ophthalmologist appointment, and they can see odd vascular changes in your retina, that could potentially represent something that is also happening in your brain,” said Alaina Reagan, a neuroscientist at JAX who led the study alongside Gareth Howell, professor and Diana Davis Spencer Foundation Chair for Glaucoma Research. This connection between retinal and brain vascular health could make eye exams a powerful tool for early detection of neurodegenerative diseases.
The retina is part of the central nervous system and shares many characteristics with the brain. Reagan explained that the neurons, immune cells, and other cellular structures in the retina closely mirror those in the brain, and they respond similarly under disease conditions. “Your retina is essentially your brain, but it’s much more accessible because your pupil is just a hole, and we can see tons of stuff,” she said.
In the study, retinal scans of mice with the MTHFR677C>T mutation revealed vessels that were more twisted and looped than normal, a pattern that can indicate problems with blood flow and hypertension. These vascular abnormalities are not only markers of potential eye disease but also reflect systemic issues that could affect the brain and other organs. This finding adds to growing evidence that blood vessel health plays a central role in the development of Alzheimer’s and related dementias.
I found this detail striking: the same research team previously observed similar vascular changes in the brains of mice with the same mutation. In their 2022 study, they noted reduced vessel density and blood flow in the cortex, the brain’s outer layer responsible for many higher-order functions. The consistency of these findings between the brain and retina strengthens the case for using eye health as a proxy for brain health.
Beyond blood vessel changes, the researchers also detected disruptions in how retinal and brain cells manage energy, clear out damaged proteins, and maintain structural integrity. These molecular alterations suggest that the MTHFR677C>T mutation affects multiple systems simultaneously, reinforcing the idea that the retina and brain are functionally interconnected.
Importantly, the study also explored how age and sex influence these vascular changes. Female mice with the mutation showed more severe outcomes, including reduced vessel density and branching by 12 months of age. This echoes broader epidemiological patterns, as women are statistically more likely to develop dementia than men, according to the World Health Organization.
To determine whether these findings apply to humans, the JAX team is partnering with clinicians and dementia care specialists at Northern Light Acadia Hospital in Bangor, Maine. Their goal is to investigate whether similar retinal changes occur in people with the MTHFR677C>T mutation and whether these changes can be detected through routine eye exams. If so, this could open a new frontier in early Alzheimer’s detection.
“Most people over 50 have some kind of vision impairment and get checked annually for prescription changes,” Reagan noted. “Are they more at risk if they have these vascular changes, and is that a point when doctors could start mitigating brain changes?” This question underscores the potential for eye exams to serve not only as a diagnostic tool but also as a preventive measure, identifying at-risk individuals long before cognitive symptoms emerge.
The implications of this research are significant. Alzheimer’s and other dementias are complex conditions influenced by a combination of genetic and environmental factors. While no single test can capture the full picture, the ability to detect early vascular changes in the retina could provide a valuable piece of the puzzle. It could also help clinicians personalize care by identifying patients who may benefit from closer monitoring or early interventions.
As the science continues to evolve, the integration of retinal imaging into routine health screenings could become a practical and noninvasive way to assess brain health. For now, the research offers a hopeful glimpse into how advances in eye care might contribute to the fight against neurodegenerative disease.
Read more at medicalxpress.com
