Regular eye checks could spot Alzheimer's disease years before it starts debilitating patients' lives, new research has shown.
Two techniques have been tested to detect beta-amyloid protein in the retina and lens of the eye. It is a key indicator that someone has Alzheimer's when clumps of the protein are detected.
The first study, carried out by the Australian science agency, the Commonwealth Scientific and Industrial Research Organisation, involved 200 volunteers, who were asked to take curcumin tablets, which binds strongly to the protein, and would be detected in the eye using images.
Preliminary results revealed 40 participants were tested with Alzheimer's and identified more than 80% of those who did not carry the condition.
The second test was carried out by US company Cognoptix Inc, who used a florescent solution to identify beta-amyloid in the lens of the eye. Out of 40 volunteers 85% accurately came back as having the disease.
The research has been labelled a 'game changer' in the treatment of the condition.
Shaun Frost, from the Australian science agency, who led the first study, said: "We envision this technology potentially as an initial screen that could complement what is currently used: brain PET imaging, MRI imaging, and clinical tests.
"If further research shows that our initial findings are correct, it could potentially be delivered as part of an individual's regular eye check-up."
Dr Doug Brown, director of research at the Alzheimer's Society, said: "Finding new and better ways to detect the early stages of Alzheimer's disease could be a game changer for both future research and for people who will develop the condition.
"These studies provide proof of principle that scanning the eye for amyloid could give us insight about what is going on in the brain.
"However as they are only preliminary studies, the eye scans will need further validation before they could be used on people with dementia."
Two other studies carried out at Harvard Medical School and Columbia University also showed people with a poorer sense of smell could be presenting an early sign of the disease.
All four trials were presented at the Alzheimer's Association International Conference,
Dementia affects 820,000 people in the UK and around 23 million of the UK population have a close friend or family member with the condition.