Clinical trials are to start in this month to test the technology in humans, researchers said.
The research builds upon previous work in cells by detecting changes in the retina of mice predisposed to develop Alzheimer's.
"Effective treatments need to be administered well before patients show actual neurological signs," said Robert Vince, of the University of Minnesota (UMN).
"Since there are no available early detection techniques, drugs currently cannot be tested to determine if they are effective against early Alzheimer's disease, Vince said.
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Looking through the eye to see the brain is a key advantage of the new technology.
"The retina of the eye is not just 'connected' to the brain - it is part of the central nervous system," said author Swati More, from the the Centre for Drug Design at UMN.
While the brain and retina undergo similar changes due to Alzheimer's disease, unlike the brain, the retina is easily accessible to us, making changes in the retina easier to observe, researchers said.
"We saw changes in the retinas of Alzheimer's mice before the typical age at which neurological signs are observed," said More.
The research was published in the journal Investigative Ophthalmology and Visual Science.