Australian scientists have found a way to check the health of a person's brain, by looking deep into the eyes.
Images of the tiny blood vessels in the retina, at the rear of an eyeball, can be used to predict a person's long-term risk of damaging "mini-strokes", the forerunner to a major stroke or dementia.
Dr Ning Cheung, from the Centre for Eye Research Australia (CERA), led the study which examined retinal photographs along with MRI brain scans of 810 middle-aged Australians over 10 years.
"You can see bleeding, leakages and all sorts of changes in the retina," Dr Cheung told AAP on Tuesday.
"Those changes are known as retinopathy, and we know them quite well because they are associated with hypertension (high blood pressure) and diabetes. "What's more important though, after this study, we can now say when you have those changes you will most likely develop changes in the brain.
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"It's a way to predict what is going to happen in the brain."
The research found those participants who had abnormalities in their retina were two to three times more likely to experience a mini-stroke during the decade-long study window.
A mini-stroke, also known as a silent brain infarct, is a blockage of blood supply which affects only a small area of the brain.
They can have no or minimal effect on cognitive function but their presence does double a sufferer's risk of a later and more damaging stroke or dementia.
A conventional MRI scan can reveal only the damage caused by a mini-stroke and, until now, there has been no easy way to evaluate a person's risk of suffering one.
"Mini-strokes are the early warning signs and we want to detect them even earlier," Dr Cheung said.
He said retinal images were a "unique, non-invasive way to view the health of the brain", the process was cheap compared with other medical imaging and the technology was already widely available.
Dr Cheung hopes his research will be turned into a clinical test that doctors could use to highlight a person's mini-stroke risk and, ultimately, help to reduce cases of stroke and dementia.
"The test could be an early warning to people with retinal abnormalities to better control risk factors like smoking, hypertension, diabetes and cholesterol, to help prevent silent brain infarct," he said.
CERA conducts research into the leading causes of blindness. It incorporates the Department of Ophthalmology at the University of Melbourne and is located at the Royal Victorian Eye and Ear Hospital.
