Many of us are familiar with the popular metaphor, “The eyes are the windows to the soul.” It is interpreted to mean that our eyes can indicate how we think and feel. Historically, an early form of the saying originated in the Bible, as shared in Matthew 6:22. The eye is the lamp of the body. If your eyes are healthy, your whole body will be full of light. Today, scientists are learning that our eyes do hold special information, that they may tell us significant things about our health. But, can they predict diseases such as Alzheimer’s? It is believed so.
Alzheimer’s is a debilitating disease in which memory loss and cognitive decline occur. Early detection is key as damage to the brain can take place years before symptoms are present. According to futurity.org, “Scientists estimate that Alzheimer’s-related plaques can build up in the brain two decades before the onset of symptoms, so researchers have been looking for ways to detect the disease sooner.” In the U.S. an estimated 5.5 million people have Alzheimer’s, per the National Institute of Ageing. The Centers for Disease Control and Prevention (CDC) predicts that by 2060, the number of Americans with Alzheimer’s is expected to hit 15 million.
A study presented in JAMA Ophthalmology, suggests the probability that one day a simple and non-invasive eye exam will be used to detect Alzheimer’s disease before the onset of symptoms. In the study, researchers at Washington University School of Medicine in St. Louis detected evidence suggesting Alzheimer’s in older patients, using a noninvasive technique called optical coherence tomography angiography. The participants of the study had the median age of 75 and none exhibited clinical symptoms of Alzheimer’s disease. However, roughly half of the people in the study had elevated levels of Alzheimer’s proteins as detected through other invasive testing such as PET scans.
Using the technique, doctors examined the retinas of the eyes of 30 patients. In the patients with elevated levels of proteins, a significant thinning in the center of the retina was noted. In addition, as explained by Rajendra S. Apte, MD, the Paul A. Cibis Distinguished Professor of Ophthalmology and Visual Sciences, “All of us have a small area devoid of blood vessels in the center of our retinas that is responsible for our most precise vision. We found that this zone lacking blood vessels was significantly enlarged in people with preclinical Alzheimer’s disease.” In the study, the retinas appeared normal in the patients who did not have pre-clinical Alzheimer’s. Dr. Rajendra S. Apte explains the eye-brain relationship. “The retina and central nervous system are so interconnected that changes in the brain could be reflected in the cells of the retina.” Though the connection is not yet fully understood, researchers note that the eyes appear to have the ability to mirror what is going on in the brain. This new finding holds the promise of being a future screening tool for Alzheimer’s, and possibly other diseases down the road, prior to the occurrence of symptoms. Thus, it can be considered an exciting advancement in the world of medicine and a game changer in the disease fighting arena. Further studies will tell us more.