Simple eye test may diagnose Alzheimer's before symptoms appear

New research indicates that a simple non-invasive eye exam may one day offer the solution to detecting Alzheimer's disease before symptoms appear. The secret lies in the center of the retina, which may thin considerably in individuals with high levels of proteins associated with the disease. Researchers found signs of reduced blood flow, as well.

Alzheimer's disease is diagnosed when symptoms appear, but past research has indicated that abnormal proteins may accumulate in the brain for years before those symptoms arise. Lumbar punctures and PET scans enable doctors to detect the elevated levels of these proteins, which indicate the presence of preclinical Alzheimer's.

Researchers with Washington University in St. Louis have found evidence that the presence of these abnormal proteins may also result in changes to the eye that a relatively standard eye test can detect. The process involves an optical coherence tomography angiography, which researchers performed on 30 volunteers.

The volunteers had an average age of "mid 70s," and though none had clinical symptoms of Alzheimer's disease, about half were found using PET scans or lumbar punctures to have elevated proteins associated with the disease.

The study found that participants with elevated protein levels also had "significant thinning" in the retina's center, which was also "significantly enlarged." As well, and thanks to the angiography part of the test, the researchers also found signs of reduced blood flow. In contrast, participants without elevated protein levels were found to have normal retinas.

SOURCE: EurekAlert