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Retina scan may give early warning of Alzheimer’s disease

A new study shows that a scan of your retina may be a relatively easy and inexpensive way to test for early Alzheimer’s disease.

The study builds on recent research showing that closely examining the retina might help detect Alzheimer’s in its early stages. The retina is made up of brain tissue. Retinas are connected to the brain via the optic nerve. Changes in the brain from dementia, including Alzheimer’s, can sometime show up in the retina.

In a small study, researchers at Washington University in St. Louis identified about 30 people with no signs of Alzheimer’s. They then tested all participant in two different ways to masure biological changes associated with the disease. One is a PET scan of the brain. The other is an examination of spinal fluid.

A little more than half of the people tested showed no signs of Alzheimer’s in the biological tests. The others had biological signs or markers of the disease. These markers are proteins or clusters of proteins found in the brains of people with Alzheimer’s.

OCT Imaging

Next, the researchers scanned the eyes of everyone in the study. They used a scan called optical coherence tomographic angiography (OCTA), which creates a detailed cross-section of the retina. OCTA scanning can map blood vessels in the retina.

They found changes in the retinas of the people who also had biological signs of Alzheimer’s. The people without Alzheimer’s markers had normal retinas.

The biological tests for Alzheimer’s, looking at spinal fluid or a brain PET scan, are complicated, expensive, and pose risks for patients. They are rarely used to diagnose the condition.

Most Alzheimer’s is diagnosed through memory tests or observing behaviour changes but by the time changes in behaviour are noticed, the disease can be in it’s advanced stages. While Alzheimer’s has no cure, medications and social programs may slow the disease. Experts are keen to find ways to diagnose Alzheimer’s earlier.

The eye is one of the few parts of the body where an ophthalmologist can see blood vessels, nerves and other tissues that are usually hidden. And for some conditions, changes in the eye may be the first sign of trouble. Diabetes, high blood pressure, autoimmune diseases, sexually transmitted diseases and cancers have all been diagnosed from eye exams. And eye exams have even saved lives that would have been lost to stroke.


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