Eye tests could spot signs of Alzheimer’s years before symptoms first appear, new research suggests

Promising research has suggested that a routine eye test could detect signs of Alzheimer’s disease years before symptoms appear.

Experts from City St George’s, University of London, say early-stage cognitive decline could soon be detected with an AI tool that measures changes in the blood vessels at the back of the eye, being rolled out in opticians and ophthalmologists’ practices.

The tool, tested using the health records of more than 500,000 Britons, could help detect and treat people with dementia before the disease causes significant damage to their brains.

Pioneering research by scientists in China suggests that the thickness of the retina, the light-sensitive tissue covering the back of the eyes, may also help predict disease.

Around 1 million people in the UK are living with dementia; This figure is expected to rise to over 1.4 million by 2040. The disease remains the UK’s biggest killer, causing 76,000 deaths each year. Last year The Mail on Sunday and the Daily Mail launched the Beating Dementia campaign together with the Alzheimer’s Society to raise awareness, increase early detection, increase research and improve care.

There is no cure for this condition, which is caused by protein buildup or reduced blood flow in the brain.

In 2024, lecanemab and donanemab, the first drugs that can slow Alzheimer’s disease, were approved for use in the UK.

But NHS chiefs have refused to fund these expensive infusion drugs because they have only been shown to slow the progression of the disease for less than a year. But experts say these drugs and others like them could be even more effective if given to patients as soon as they develop dementia, before they cause too much harm.

But for many Britons, the condition does not improve even years after symptoms begin; A recent study by University College London reveals that it takes approximately 3.5 years for patients to be diagnosed.

But now researchers at City St George’s have found a new approach; They looked for signs of cognitive decline during routine eye exams.

Every year, thousands of older adults have photos taken of the back of their eyes to check for changes in their retinal blood vessels. Research shows that these are closely connected to the vessels in the brain and may show signs of neurodegeneration.

Experts believe the retina may predict Alzheimer’s risk because the retina is part of the central nervous system and is directly connected to the brain via the optic nerve.

Everyone experiences dementia differently. Use this checklist to help you note your symptoms before talking to your doctor.

This makes the eye vulnerable to degeneration in the brain caused by Alzheimer’s disease, including nerve cell loss, inflammation, and vascular damage.

Thinning of the retina can also be a sign of brain changes, such as decreased brain volume and atrophy (gradual weakening).

A study published earlier this year by scientists at the Jackson Laboratory in the US found that people with changes in these tiny blood vessels were more likely to have a common genetic mutation known to increase the risk of Alzheimer’s.

They also discovered that blood vessels that are more twisted and tortuous than normal can limit the way nutrients and oxygen are transported.

New research suggests eye tests can detect signs of Alzheimer’s disease years before symptoms first appear (Stock image)

To analyze thousands of images, the Alzheimer’s Society-funded City St George research team used an AI tool that can measure the exact width and area of ​​the vessels and found that changes in retinal vessels were strongly linked to lower cognitive test scores.

City St George’s principal investigator Misha Ramesh said: ‘This will help predict neurodegenerative disease before symptoms begin.’

Last year, this newspaper reported that researchers had developed a nasal swab test that could detect dementia decades before symptoms begin to appear.

Scientists at the University of Southampton say that, if successful, the swab test could provide results ‘within minutes’.