Prompt low-cost eye test may help detect Alzheimer's disease says new study


Devdiscourse News Desk | Washington DC | Updated: 12-03-2019 15:22 IST | Created: 12-03-2019 15:07 IST
Prompt low-cost eye test may help detect Alzheimer's disease says new study
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A quick low-cost eye test may one day help detect Alzheimer's disease non-invasively before symptoms of memory loss are evident, according to a study led by an Indian-origin researcher. The study, publishing in the journal Ophthalmology Retina, involving over 200 people suggests the loss of blood vessels in the retina could signal Alzheimer's disease.

In people with healthy brains, microscopic blood vessels form a dense web at the back of the eye inside the retina, as seen in 133 participants in a control group. In the eyes of 39 people with Alzheimer's disease, that web was less dense and even sparse in places.

The differences in density were statistically significant after researchers controlled for factors including age, sex, and level of education. "We know that there are changes that occur in the brain in the small blood vessels in people with Alzheimer's disease," said Dilraj S Grewal, an ophthalmologist at Duke Eye Center in the US and a lead author on the study.

"Because the retina is an extension of the brain, we wanted to investigate whether these changes could be detected in the retina using a new technology that is less invasive and easy to obtain," Grewal said in a statement. "We are measuring blood vessels that can't be seen during a regular eye exam and we are 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 from Duke University Medical Center in the US.

"It's possible that these changes in blood vessel density in the retina could mirror what is going on in the tiny blood vessels in the brain, perhaps before we are able to detect any changes in cognition," he said. The study found differences in the retinas of those with Alzheimer's disease when compared to healthy people and to those with mild cognitive impairment, often a precursor to Alzheimer's disease.

Scientists at Duke Eye Center and beyond have studied other changes in the retina that could signal trouble upstream in the brain, such as thinning of some of the retinal nerve layers. The study used a noninvasive technology called optical coherence tomography angiography (OCTA). OCTA machines use light waves that reveal blood flow in every layer of the retina.

An OCTA scan could even reveal changes in tiny capillaries -- less than half the width of a human hair -- before blood vessel changes show up on a brain scan such as an MRI or cerebral angiogram, which highlight only larger blood vessels. Such techniques to study the brain are invasive and costly, researchers said.

"Ultimately, the goal would be to use this technology to detect Alzheimer's early, before symptoms of memory loss are evident, and be able to monitor these changes over time in participants of clinical trials studying new Alzheimer's treatments," Fekrat said.

(With inputs from agencies.)

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