Eye Scans Can Now Reveal Early Risk of Dementia

According to a recent study, changes in the retinal blood vessels at the back of the eye may reveal early risk factors for dementia. Researchers found that wider veins and narrower arteries in the retina are directly associated with Alzheimer's disease and related dementias.

Interestingly, these vascular patterns proved to be more accurate predictors than the commonly used retinal nerve fiber layer thickness measurements.

This evidence supports the growing body of research suggesting that retinal tissue could serve as a neurological screening tool. In the early stages of brain degeneration, changes are also reflected in the retina, as this tissue shares anatomical structures and blood circulation patterns with the brain.

Retinal imaging is emerging as a promising early screening tool. It offers fast, non-invasive, and currently accessible measurement techniques. While experts agree that these findings are not yet ready for immediate clinical application, they lay a strong foundation for future research and long-term monitoring strategies.

Routine eye exams in middle age could eventually lead to improved brain health by helping identify risks early and enabling preventive care.

Your future eye exam might serve dual purposes—checking your vision while also offering insights into potential cognitive decline.

This groundbreaking finding marks a significant milestone in using the eyes as a window into brain health. Scientists now believe the eyes may help predict dementia risk, offering a new path to early detection of neurodegenerative diseases.

Researchers at the University of Otago in New Zealand provided compelling evidence that retinal changes may be linked to increased risk of Alzheimer’s Disease and Related Dementias (ADRD). The study involved 938 participants, all aged 45, from the globally recognized Dunedin Multidisciplinary Health and Development Study. This long-term study tracks individuals born in Dunedin, New Zealand, in the early 1970s.

The distinctive research data enabled scientists to evaluate dementia warning indicators in middle age before dementia-related cognitive symptoms started to appear.

Scientific researchers examined precise features of retinal microvasculature which included retinal arteriole widths and venules widths as their key measures.

• A direct correlation emerged between retinal arteriole width and venule width measurements and participant dementia risk according to tested scores such as the Alzheimer’s Disease Genetic Risk Score and the Dementia Risk Score (CAIDE).

• Retinal vascular changes proved superior at predicting other ophthalmic markers to detect dementia such as retinal nerve fiber layer thickness.

Why is this important?

Experts consider the retina an extension of the central nervous system. It shares tissue structure, blood supply, and embryological development with the brain. Damage to brain microvessels and other neurodegenerative changes often manifest similarly in the retina.

Therefore, retinal imaging provides a safe and non-invasive way to detect early structural brain changes that occur before dementia symptoms appear.

This study focuses on individuals in their 40s to detect signs of Alzheimer's disease as early as possible. Detecting these signs early allows for the potential implementation of lifestyle changes, medical interventions, and close monitoring—well before significant brain damage and cognitive symptoms arise.

Lead author Dr. Ashleigh Barrett-Young explained that symptoms like memory loss and confusion typically surface only after considerable brain deterioration. Early identification of at-risk individuals opens the door to preventive care and delayed disease progression.

These findings carry significant weight in the global context. According to the World Health Organization, more than 55 million people currently live with dementia worldwide—a number expected to double in the coming decades.

Early detection is considered one of the most effective strategies in combating neurodegenerative diseases, especially as no definitive cure exists yet.

While retinal imaging is not ready for diagnostic use, it shows promise. More research involving diverse populations and age groups is necessary to confirm its effectiveness. Scientists must also further investigate how exactly retinal blood vessel changes reflect central nervous system health.

Since retinal imaging is already a routine, low-cost part of eye exams, it holds practical potential. With further validation, it could become a standard tool for midlife health screenings—identifying dementia risks up to three decades before clinical symptoms emerge.

In the near future, a visit to your optometrist may not only check your eyesight but also provide valuable clues about your cognitive health.

References:

1. Barrett-Young A;Reuben A;Caspi A;Cheyne K;Ireland D;Kokaua J;Ramrakha S;Tham YC;Theodore R;Wilson G;Wong TY;Moffitt T; (n.d.). Measures of retinal health successfully capture risk for alzheimer’s disease and related Dementias at midlife. Journal of Alzheimer’s disease : JAD. https://pubmed.ncbi.nlm.nih.gov/40033783/

(Input from various sources)

(Rehash/Farhath Sulthana/MSM)