Experts believe the key to tackle the incurable brain condition, and stopping it, lies in early detection.
The study led by Lancaster University has shown that people with Alzheimer's have difficulty with one particular type of eye tracking test, the 'Daily Express' reported.
During the study, 18 patients with Alzheimer's, 25 patients with Parkinson's, 17 healthy young people and 18 healthy older people were asked to follow the movements of light on a computer. In some instances they were asked to look away from the light.
Detailed eye-tracking measurements taken from the group showed stark contrasts in results.
Alzheimer's patients made errors when they were asked to look away from the light and were unable to correct those errors.
This was despite them being able to respond perfectly normally when asked to look towards the light.
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These errors were 10 times more frequent in the Alzheimer's patients compared with the control groups.
The researchers also measured memory function among Alzheimer's patients who found the test difficult, which revealed a clear correlation with lower memory function.
Dr Trevor Crawford, of the department of Psychology and the Centre for Ageing Research at Lancaster University, said these new results were potentially very exciting as they demonstrated, for the first time, a connection with the memory impairment that is so often the first noticeable symptom in Alzheimer's disease.
"The diagnosis of Alzheimer's disease is currently heavily dependent on the results of a series of lengthy neuropsychological tests," Crawford said.
"However, patients with a dementia often find that these tests are difficult to complete due to a lack of clear understanding and lapse in their attention or motivation.
"The light tracking test could play a vital role in diagnosis as it allows us to identify and exclude alternative explanations of the test results," he said.
Alzheimer's disease is a devastating disorder, which starts many years before the symptoms begin to appear.
The study is published in the Journal of the American Ageing Association.