Biomedical engineers at Duke University have devised a new imaging device capable of measuring both the thickness and texture of the various layers of the retina at the back of the eye.
It is hoped that the technology could be used to detect a biomarker of Alzheimer’s disease, potentially offering a widespread early warning system.
An Alzheimer’s disease diagnosis is currently only made after a patient begins to show symptoms of cognitive decline.
Even then, the only way to definitively determine that Alzheimer’s is the cause is with expensive MRI and PET scans or through an autopsy. But if disease progress can be halted through early interventions such as drugs and mental exercise, patients can have a greatly improved quality of life. This is why researchers are looking for biomarkers that could be used as early warning signs of the disease.
One such potential biomarker comes from the retina, which is literally an extension of the brain and part of the central nervous system.
Previous research has shown that Alzheimer’s can cause structural changes to the retina, most notably a thinning of the inner retinal layers.
Professor Adam Wax from Duke University said the new imaging device showed that there was more detail available when attempting to diagnose Alzheimer’s.
“Previous research has seen a thinning of the retina in Alzheimer’s patients, but by adding a light-scattering technique to the measurement, we’ve found that the retinal nerve fibre layer is also rougher and more disordered,” explained Prof. Wax.
“Our hope is that we can use this insight to create an easy and cheap screening device that wouldn’t only be available at your doctor’s office, but at places like your local pharmacy as well.
“The retina can provide easy access to the brain, and its thinning can be indicative of a decrease in the amount of neural tissue, which can mean that Alzheimer’s is present.”
Other diseases such as glaucoma and Parkinson’s disease, however, can also cause a thinning of the retina.
In the new study, Prof. Wax shows that the topmost layer of neurons in the retina of a mouse model of Alzheimer’s disease exhibit a change in their structural texture.
Combined with data on the changes in thickness of this layer, the new measurement could prove to be a more easily accessible biomarker of Alzheimer’s.
“Our new approach can measure the roughness or texture of the nerve fibre layer of the inner retina,” said graduate student Ge Song.
“It can provide a quick and direct way to measure structural changes caused by Alzheimer’s, which has great potential as a biomarker of the disease.”
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