Alzheimer's could be detected early through eyes
SCIENTISTS believe they have hit upon an early-warning system for identifying Alzheimer's, after two separate new studies identified a "biomarker" of the disease that can be spotted in an eye test.
Early trials of two different techniques reveal that an indicator for the degenerative disorder can be identified in the retina and lens of the eye.
Both methods were able to distinguish between probable Alzheimer's patients and healthy volunteers with a high level of accuracy.
The scientists behind both projects stressed that their research was still at a very early stage but expressed hope that it could be developed into an eye test which could be used to identify people with the disease.
Dr Simon Ridley, head of science at the Alzheimer's Research UK charity welcomed the research.
"It is difficult to diagnose Alzheimer's disease accurately and, in many cases, by the time the symptoms have developed, damage has already been going on in the brain for a number of years," he said.
"The development of a quick, cheap, non-invasive test to detect Alzheimer's would be an important step in helping people receive an early diagnosis, and helping to improve clinical trials so that potential new treatments have the best chance of success," Dr Ridley added.
The scientists envisage using an eye test as the first step to identifying possible cases of Alzheimer's, with would be followed by more expensive procedures to confirm the presence of the disease. These include PET - positron emission tomography - scans or spinal fluid analysis.
New methods are being used to detect Alzheimer's New methods are being used to detect Alzheimer's Shaun Frost, from the Australian science agency the Commonwealth Scientific and Industrial Research Organisation, who led one of the studies, said: "We envision this technology as an initial screen that could complement what is currently used…If further research proves our findings are correct, it could potentially be delivered as part of an individual's regular eye check-up."
"The high resolution of our images could also allow accurate monitoring of individual retinal plaques as a possible method to follow progression and response to therapy," Mr Frost added.
The eye tests are based on the fact that the eye is effectively an extension of the brain. Both studies looked for signs of beta-amyloid protein, which forms in clumps in the brains of Alzheimer's patients and is a key hallmark of the disease.
The Australian study used curcumin, the turmeric spice ingredient, as a fluorescent marker that binds closely with beta-amyloid, allowing it to show up in the retina.
Volunteers were asked to take supplement of curcumin , which was then detected in the eye using a novel imaging system. Preliminary results on 40 participants showed that the test picked up every participant with Alzheimer's and correctly identified those shown in the brain by PET imaging.
In the other study, researchers from the US company Cognoptix used an ointment to apply a flouescent label to beta-amyloid in the lens of the eye. Laser scanning was then able to detect the protein. In tests of 40 volunteers with and without Alzheimer's, it identified those having the disease with 85 per cent accuracy.