Study finds eye test may spot Alzheimer's before symptoms appear

A non-invasive eye test may one day be used to screen patients for Alzheimer's disease, according to a new study. The test involves looking at blood vessels in the retina, but isn't something that currently takes place as part of a normal eye test. The process is described as quick, involving 'relatively new' technology that can capture high-resolution images of the small blood vessels.

Alzheimer's disease is currently diagnosed once symptoms appear, such as memory troubles and perception problems. Past research has sought a way to diagnose the disease at an earlier stage, potentially making it possible to start treatment or make lifestyle changes to help mitigate the progression. A reliable, inexpensive, and non-invasive solution has remained elusive, however.

A study at Duke Eye Center may have found a suitable method, however, and it involves small blood vessels in the retina. In cases of Alzheimer's disease, these microscopic vessels are found inside the retina as a dense web. That appearance signifies a healthy brain, but in cases of Alzheimer's disease, the blood vessels appear different.

According to the research, these patients have less dense vessel webs in their retinas that could even be 'sparse' in some areas. After controlling for other factors, the researchers found this change to be statistically significant. The blood vessel changes may be the result of changes in the brain that signify Alzheimer's disease.

The blood vessel changes were noted in the eyes of 39 Alzheimer's patients as part of a study involving 133 people in a control group. The test involved a machine that performed optical coherence tomography angiography (OCTA), a non-invasive procedure that only takes a few minutes.