An easy non-invasive eye-tracking test may diagnose Alzheimer's, researchers in Britain suggest.

Dr. Trevor Crawford of the Department of Psychology and the Center for Ageing Research at Lancaster University in England said currently the diagnosis of Alzheimer's disease is dependent on the results of a series of lengthy neuropsychological tests that many elderly have difficulty taking, The Daily Telegraph reported.

The study involved 18 patients with Alzheimer's disease, 25 patients with Parkinson's disease, 17 healthy young people and 18 healthy older people were asked to follow the movements of light on a computer monitor.

In some instances the study participants were asked to look away from the light.

Patients with Alzheimer's made errors on the task when they were asked to look away from the light -- they were unable to correct those errors, despite being able to respond normally when they were asked to look towards the light.

The study, published in the Journal of the American Aging Association, found uncorrected errors were 10 times more frequent in the Alzheimers' patients than the control groups.

The researchers also measured memory function among those Alzheimer's patients who found the test difficult and were able to show a clear correlation with lower memory function, Crawford said.