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Eye test for Alzheimer’s ‘could be game-changer’

Breakthrough: Microscopic blood vessels at the back of the eye could pre-determine the early onset of Alzheimer's PICTURE: SHUTTERSTOCK

A NEW eye test could be used to spot early signs of Alzheimer’s disease, research has suggested.

The test, which highlights microscopic blood vessels at the back of the eye, has the potential to detect the disease before symptoms appear, scientists claim.

Experts agree that early diagnosis of Alzheimer’s is vital to the effectiveness of therapies aimed at slowing, halting or reversing the disease.

An early study found that tiny blood vessels that normally form a dense web at the back of the eye become sparser in Alzheimer’s patients.

The differences seen were statistically significant after adjusting for factors such as age, sex and education and the new research raises the prospect of opticians with access to the technology checking brain health at the same time as they update spectacle prescriptions.

Dr Sharon Fekrat, from Duke University Medical Centre in the US, said: ‘We’re measuring blood vessels that can’t be seen during a regular eye exam and we’re doing that with relatively new non-invasive technology that takes high-resolution images of very small blood vessels within the retina in just a few minutes.

‘It’s possible that these changes in blood vessel density in the retina could mirror what’s going on in the tiny blood vessels in the brain, perhaps before we are able to detect any changes in cognition.’

Potentially the test could spot warning signs of Alzheimer’s before vascular abnormalities show up on brain scans, which can only highlight larger blood vessels, she added.

The imaging technique, known as optical coherence tomography angiography (Octa), allows doctors to see retinal blood vessels smaller than the width of a human hair.

For the study, scientists used Octa to compare the retinas of 39 Alzheimer’s patients, 37 people with mild cognitive impairment, and 133 ‘healthy’ individuals with normally functioning brains.

They found that the blood vessel network was less dense in the Alzheimer’s patients compared with the other groups.

In addition a specific layer of the retina was thinner in participants with Alzheimer’s.