A simple eye test carried out by your optician could pick up Alzheimer's Disease years before it develops and lead to early treatment to stop it in its tracks, claim scientists.
By Richard Alleyne, Science Correspondent
Published: 2:29PM GMT 14 Jan 2010
British researchers have developed a technique that highlights nerve cell damage in the retina of the eye which they have proved correlates exactly to nerve cell damage in the brain.
They say the quick, noninvasive and cheap test, which only involves applying eye-drops and then taking a photo with an infra-red camera, could revolutionise detection of dementia. Once diagnosed, treatment could begin immediately.
"Few people realise that the retina is a direct, albeit thin, extension of the brain," said Professor Francesca Cordeiro, lead author at University College London.
"It is entirely possible that in the future a visit to an eye doctor to check on your eyesight will also be a check on the state of your brain."
The technique, which is just starting human trials and could be available within two years, involves highlighting nerve cell damage in the eye using a chemical marker that glows when it finds it.
This can either be administered as an injection in the arm or eye-drops.
Once the substance is in the body it seeks out nerve cells that are dying and chemically marks them. All opticians and doctors need then do is use an infrared camera to take a picture of the eye and count how many dots appear in the photo.
Researchers, who published their findings in the journal Cell Death & Disease, have calculated that anything more than 20 could indicate the early onset of Alzheimer's.
Professor Cordeiro, who worked with Professor Stephen Moss, said: "The death of nerve cells is the key event in all neuro-degenerative disorders – but until now it has not been possible to study cell death in a living eye.
"Early diagnosis of Alzheimer's is critical in order to stop and reverse the cell death before it is too late. Once brains cells are dead there is no way to revive them.
"If you catch Alzheimer's Disease early enough you can slow it down and even reinvigorate the cells."
Alzheimer's charities welcomed the research and said it could change the way the disease is studied, diagnosed and monitored.
Dr Susanne Sorensen, head of research at the Alzheimer's Society, said: ""We know as Alzheimer's disease develops, cells in the brain die and the brain shrinks.
"The study of this disease has been hampered by the difficulty of following the progress directly in the human brain. This research is very exciting as it opens up the possibility of observing individual cells on the human retina using a relatively non-invasive procedure.
"In the longer term this technique could be used for diagnostic purposes or to help researchers monitor the effects of drugs under development. However, much more research needs to be done before we know if we can get to this stage."
Rebecca Wood, chief executive of the Alzheimer's Research Trust, said: "Although this study uses animals, it is hoped that the technique can be modified for human use. These findings have the potential to transform the way we diagnose Alzheimer's, greatly enhancing efforts to develop new treatments and cures.
"If we spot Alzheimer's in its earliest stages, we may be able to treat and reverse the progression of the disease as new treatments are developed. Dementia scientists currently lack a way of assessing the brain's responses to new treatments in real-time. This technique may help overcome that obstacle."
Alzheimer's is the most common form of dementia, which affects around 700,000 people in the UK.
One million Britons are expected to develop dementia in the next 10 years.