The study also found differences in the retinas of those with Alzheimer's disease compared to healthy people and to those with mild cognitive impairment which is often a precursor to Alzheimer's disease.
It enables physicians to see blood vessels in the back of the eye that are smaller than the width of a human hair.
"The retina is an extension of the brain", Grewal said.
In addition to the 200 participants, researchers studied 133 healthy control subjects; 39 with Alzheimer's disease, and 37 with mild cognitive impairment (MCI).
Previously researchers have known about the changes that occur in the brain and in the small blood vessels in people with Alzheimer's disease.
IBM also claims that amid the wide range of other proposed blood tests for Alzheimer's disease that are now being developed, this is the first study to use machine learning to identify sets of proteins in the blood that are predictive of a biomarker in spinal fluid. For those with Alzheimer's, the same vessels are sparse and lacking in different areas.
Early diagnosis will allow researchers to administer them sooner in the disease process which may lead to better results.
Diagnosing Alzheimer's is a challenge.
This research, when it comes into fruition, can help the field of medicine take one step forward to the potential of detecting Alzheimer's disease at a budding stage through machine learning, AI and technology. Earlier diagnosis would also give patients and their families time to plan for the future. OCTA machines used light waves that reveal blood flow in every layer of the retina.
"It's possible that these changes in blood vessel density in the retina could mirror what's going on in the tiny blood vessels in the brain, perhaps before we are able to detect any changes in cognition", added Sharon Fekrat, ophthalmologist at the Duke University in the US. Such techniques to study the brain are invasive and costly.
They say this loss of blood vessels may mirror what's going on in other tiny blood vessels in the brain, even before a patient develops memory loss.
Upwards of 5.5 million Americans are estimated to possibly have the brain wasting disease, according to NIH, and these numbers will continue to increase in years to come if no cure is found, projections suggest an impending and staggering global impact of dementia and neurodegenerative diseases.