Scientists in Australia report encouraging early results from a simple eye test they hope will give a noninvasive way to detect signs of Alzheimer's disease.

Although it has been tried on just a small number of people, the experimental test has a solid basis: Alzheimer's is known to cause changes in the eyes, not just the brain. U.S. scientists are working on a similar test .

The eye study involved photographing blood vessels in the retina, the nerve layer lining the back of the eyes. Most eye doctors have the cameras used for this, but it takes a special computer program to measure blood vessels for the experimental test doctors are using in the Alzheimer's research, said the study's leader, Shaun Frost of Australia's national science agency, CSIRO.

Researchers compared retinal photos of 110 healthy people, 13 people with Alzheimer's and 13 others with mild cognitive impairment, or "pre-Alzheimer's," who were taking part in a larger study. The widths of certain blood vessels in those with Alzheimer's were different from vessels in the others, and the amount of difference matched the amount of plaque seen on brain scans.

More study is planned. The findings were discussed Sunday at the Alzheimer's Association International Conference in France.