English researchers reveal in a new study that eye problems could be an early indicator of cognitive decline. Enough to detect signs of dementia almost twelve years before the diagnosis of the disease.
Window to the soul for some, our eyes could also contain more than one indication of our physical and mental state. In February 2024, Catherine Helmer, research director at Inserm, already discussed the common mechanisms and interactions shared by ophthalmological and neurological diseases, as part of a study carried out in the cities of Dijon, Bordeaux, and Montpellier. Epidemiological and clinical links which would allow early identification of people most at risk of dementia (including Alzheimer’s disease), through a retinal examination. Significant advantage of these organs: “Their partial transparency requires much less invasive examination methods than other parts of the body,” as our colleagues at female.
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Detect the disease twelve years before diagnosis
This correlation between eye problem and cognitive decline, English researchers from Loughborough University decided to exploit it in a study relayed in the columns of the journal The Conversation this April 10. They noted a loss of visual sensitivity which could predict dementia… almost twelve years before his diagnosis.
Based on a panel of more than 8,000 participants, followed for several years, the researchers identified nearly 537 people who had developed dementia at the end of the study, allowing them to know the symptoms which had preceded the diagnosis. Each of them had to take a visual sensory test at the start of this life-size experiment, encouraging them to press a button when they saw a triangle forming in a field of moving dots. Result: participants who had developed dementia were much slower to detect this triangle compared to the others.
“Toxic amyloid plaques associated with Alzheimer’s disease may first affect areas of the brain associated with vision”, estimate the researchers. And this, before the disease progresses and damages the areas dedicated to memory. According to their research, other aspects of visual processing could also be affected, “such as the ability to see the outlines of objects (contrast sensitivity) and to discern certain colors (the ability to see the blue-green spectrum is affected early in dementia)”. Victims of the disease could also be more sensitive to distracting stimuli, causing problems controlling eye movements, but also have more difficulty imprinting a face, and therefore recognizing new people.
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Read or watch TV series to boost our memory?
If previous research remains quite mixed at this stage, the study also specifies that eye movement could boost our memory. Which would explain “why people who watch more TV and read more have better memory and less risk of dementia than those who don’t”. Both by moving one’s gaze from one page to another, or on a screen, but also because people who read more tend to be more often educated, and therefore benefit, in general, from an ability to more optimal brain reserve. To explore these findings further, the researchers say it will be necessary to operate eye tracking devices that are expensive and require additional training. Waiting for, “Using eye movements as a diagnostic tool for early-stage Alzheimer’s disease is not possible outside of the laboratory.”
Seventh cause of death in the world, dementia currently concerns “more than 55 million people” on the planet, according to the World Health Organization, “including more than 60% in low- and middle-income countries”. Early diagnosis would allow better management of the disease, and thus slow its progression.
