Three biomarkers that indicate Alzheimer's disease and mild cognitive impairment have been identified by researchers from the University of Alberta, findings which may be groundbreaking if proven worthy of use in clinical settings.
They found the blood vessel network was less dense in the Alzheimer's patients compared with the other groups.
In the past, some small studies have suggested that there would be differences "in both neuronal and microvascular retinal measures between those with and those without Alzheimer's disease", said Alison Abraham, an associate professor of ophthalmology and director of the Wilmer Eye Institute Biostatistics Center at the Johns Hopkins School of Medicine.
The new test uses non-invasive imaging called optical coherence tomography angiography (OCTA).
Potentially the test could spot warning signs of Alzheimer's before vascular abnormalities show up on brain scans, which can only highlight larger blood vessels, she added.
Citing a previous research, Goudey said: "Examining the concentration of the peptide in an individual's spinal fluid provides an indication of risk decades before any memory related issues occur".
In an online publication obtained on Monday, Goudey explained that Alzheimer has been diagnosed to be the cause of dementia - a decline in thinking and person's pattern of behaviour.
"Although there is now no single test that can accurately give an Alzheimer's diagnosis, brain scans, cognitive assessments and spinal fluid tests can all reveal clues to the disease". Earlier diagnosis would also give patients and their families time to plan for the future.
Using the OCTA that uses light waves that reveal blood flow in every layer of the retina, the researches checked more than 200 people. But such techniques to study the brain are invasive and costly.
"We're measuring blood vessels that can't be seen during a regular eye exam and we're doing that with relatively new noninvasive technology that takes high-resolution images of very small blood vessels within the retina in just a few minutes", said Sharon Fekrat, lead author of the study.
In the USA alone, 5.8 million people are living with Alzheimer's dementia, according to 2019 data from the Alzheimer's Association.