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Eye-tracking tech could revolutionise dementia screening.
They say the eyes are a window to the soul. But a groundbreaking study from the UK now suggests they may also offer an early glimpse into the onset of dementia, up to 12 years before symptoms appear.
In a revelation that has stunned the scientific community, researchers in Norfolk observed more than 8,600 healthy individuals over several years. By the end of the study, 537 of them had developed dementia. What linked them all was something subtle, yet potentially revolutionary, that how their eyes reacted to a simple visual test years earlier.
Participants were initially asked to complete a “visual sensitivity” task. They had to quickly spot a triangle formed by three moving dots on a screen and press a button in response. It seemed like a routine test, but researchers found a pattern. Those who would later develop dementia consistently responded more slowly than others.
What does vision have to do with memory loss?
Experts at Loughborough University, who led the study, believe the answer lies deep in the brain’s architecture. In Alzheimer’s disease, toxic amyloid plaques first target regions associated with visual processing, long before they attack the memory centers. That means the eyes may register subtle neurological changes years before the mind starts forgetting.
“These results are forcing us to rethink the earliest signs of Alzheimer’s,” said Dr Martyn Gould, one of the lead researchers. We’ve always looked to memory tests to catch this disease, but our eyes might tell the story long before we forget our own, he added.
The implications are vast. If this visual delay is a reliable early warning sign, it could change the way doctors screen for cognitive decline. And since vision- symptoms – such as difficulty focusing, trouble recognising faces, or poor perception of outlines and colours – are already common in dementia patients, the findings add to a growing body of evidence that Alzheimer’s begins its quiet assault long before memory fades.
For instance, people with dementia often struggle to distinguish blue and green hues, or they find it hard to filter out visual distractions. Their eye movements can become erratic, making everyday activities like reading, watching television, or driving far more dangerous. In fact, Loughborough scientists are now examining whether impaired eye coordination contributes to road accidents among elderly drivers.
Another striking observation was that patients with dementia don’t process faces the same way others do. While most people instinctively scan the eyes, nose, and mouth to recognise someone, dementia patients’ gaze often drifts toward un background objects, leading to an inability to “imprint” new faces.
This wandering gaze has even become a subtle diagnostic clue for seasoned neurologists. “We can sometimes tell something’s wrong just by how a patient’s eyes move,” said one clinician involved in the study, “They look around, but it’s like they’re not really seeing.”
There’s even growing speculation that purposeful eye movement might aid memory retention. In a separate study, rapid horizontal eye movements, about two per second, appeared to improve autobiographical memory in right-handed people. Other research suggests that the simple act of scanning a page or screen repeatedly may stimulate memory-forming pathways in the brain.
Still, eye-tracking technology remains largely confined to research labs. The equipment is expensive, and interpreting the data requires expert training. Until cheaper, user-friendly systems emerge, using eye movement as a standard diagnostic tool remains a challenge.
