Eye exam sees evidence of Alzheimer’s

Using an easy eye exam, researchers at Washington University of Medicine in St. Louis were able to detect evidence of Alzheimer’s disease in patients before they had symptoms of the disease.

The findings, involving 30 patients, were published last week in the journal JAMA Ophthalmology.

Scientists estimate that Alzheimer’s-related plaques begin accumulating in the brain two decades before the onset of symptoms. Physicians can use PET scans and lumbar punctures to detect the plaques, but the tests are expensive and invasive.

Researchers have been looking for ways to detect the disease sooner and test drugs to intervene.

Longer studies involving more people are needed, but if changes detected with the eye test can be used as markers for Alzheimer’s risk, it may be possible to screen people in their 40s or 50s.

The 30 study participants had an average age in the mid 70s. None were experiencing symptoms of Alzheimer’s.

In the new study, researchers used a technology similar to what is found in many eye doctors’ offices to measure thickness of the retina and optic nerve fibers. They added one component to the common test — angiography — which also allowed them to look at blood-flow patterns.

“In patients whose PET scans and cerebrospinal fluid showed preclinical Alzheim- er’s,” co-principal investigator Dr. Gregory Van Stavern said, “the area at the center of the retina without blood vessels was significantly larger, suggesting less blood flow.”