A study, published in the journal Ophthalmology Retina, has suggested the loss of blood vessels in the retina could signal dementia, specifically Alzheimer’s disease. Researchers found differences in the retinas of those with Alzheimer’s disease when compared to healthy people and to those with mild cognitive impairment – often a precursor to Alzheimer’s disease. The study focused on more than 200 people at the Duke Eye Center. Out of the total participants, 39 people with Alzheimer’s disease were included.
Researchers used a technique called Octa (optical coherence tomography angiography), which they say could revolutionise treatment of the devastating neurological disorder.
The non-invasive scan looks for changes in blood vessels in the retina – a coat of light-sensitive cells at the back of the brain.
Senior author Professor Sharon Fekrat, an ophthalmologist at the Duke Eye Centre in Durham, North Carolina, said: “If we can detect these blood vessel changes in the retina before any changes in cognition, that would be a game changer.”
Current dementia medications only treat the symptoms – not the cause – meaning there is still no cure. This has led to an increasing focus on prevention.
One of the main reasons new drugs have been ineffective so far is they are administered too late to trial patients – when the disease is advanced.
Early diagnosis will allow researchers to administer them sooner in the disease process which may lead to better results.
It would also give patients time to plan for the future with their families – while they still have their faculties, said Professor Fekrat and his colleagues.
Prof Fekrat said: “Early diagnosis of Alzheimer’s disease is a huge unmet need.
“It’s not possible for current techniques like a brain scan or lumbar puncture to screen the number of patients with this disease.
“It’s possible these changes in blood vessel density in the retina may mirror what’s going on in the tiny blood vessels in the brain. Our work is not done.”
She added: “We need to detect the disease earlier and introduce treatments earlier.”
According to Dr James Pickett, Head of Research at Alzheimer’s Society, this study only looked at a handful of people with Alzheimer’s disease, so we can’t be sure if a loss of blood vessels the eyes is a sign of Alzheimer’s.
He said: “We urgently need a test to identify people who might go on to develop dementia, but who aren’t showing any clinical symptoms yet. We need further studies to find out if this eye test could help us do this.
“The very earliest changes in the brain can appear up to 20 years before we see clinical symptoms, so the holy grail would be to identify and treat people the moment these changes start. The researchers we support are exploring every approach – from blood tests and brain scans, to smartphone technology and eye scans – in the hunt for ways to diagnose the condition as early as possible.
“With one million people predicted to develop dementia by 2021, and no cure for the condition, any breakthroughs in early diagnosis could make a huge difference.”
Another recent study suggested being a loud snorer can cause dementia.