An Australian study into whether a simple eye test can identify who will develop Alzheimer's disease up to 20 years before the first symptoms appear is showing promising results.

Preliminary results from the trial being conducted in Perth were presented on Sunday at the Alzheimer Association's international conference in Copenhagen.

If the final results prove positive, it is hoped a cure for the disease could ultimately be found.

Project leader Dr Yogesan Kanagasingam from the CSIRO's e-Health Research Centre said currently it was only possible to detect Alzheimer's after significant brain damage had already occurred.

"You can do brain imaging, but that is at the later stages and it's already too late," he said.

"It is the first trial in the world to prove that this kind of thing could be used for identifying the Alzheimer's disease early."

Results from 40 participants out of a total of 200 have been analysed so far, with final results to be completed by October.

Dr Kanagasingam said the preliminary results were being released because researchers were so excited by the findings.

Spice is right for disease detection

Participants in the trial consumed curcumin, a bright yellow compound found in the spice turmeric, before undergoing an eye scan.

The curcumin makes beta-amyloids glow in an eye scan.

Retina scans showing beta-amyloids in the retina of a person with Alzheimer's disease (left), and without (right). ( ABC News: Natasha Harradine )

Beta-amyloid protein is the primary material found in the sticky brain "plaques" characteristic of Alzheimer's disease.

Preliminary results from the trial in Perth show the level of beta-amyloid detected in the eye correlates with that found in the brain, allowing researchers to accurately identify those with Alzheimer's.

Jason Burton from Alzheimer's Australia said an early detection test would be significant.

"If we can identify people pre-symptomology then it gives us a new route into finding new test medications," he said.

"Looking at, can we find medications that maybe act as an immunisation to further progress of the Alzheimer's disease, or that can treat the amyloid build-up better before the brain gets to the point where it's becoming impaired in terms of everyday function."

Dr Kanagasingam said researchers around the world were looking at developing medication to treat Alzheimer's before it caused brain damage.

He said he hoped it would be a matter of only two to three years before diagnostic eye-testing was rolled out through mainstream medicine, but that could only happen once medications were available to treat the disease.

"It won't happen overnight because we also need drugs to treat the patients, which a lot of companies and research teams around the world are testing different drugs," he said.

The trials being conducted in Perth are a joint project between the CSIRO, Edith Cowan University and the McCusker Foundation.