Researchers believe that an eye test could one day be used to diagnose Alzheimer’s disease decades before symptoms generally appear. Previous research has indicated that a specific protein that affect the brains of those diagnosed with Alzheimer’s could also affect the retina of the eye. New research is indicating that the initial signs of Alzheimer’s could be detected using equipment similar to what is already available in most eye doctors’ offices.
For the latest study, the researchers were operating on the premise that since the retina and central nervous system are interconnected, the cells of the retina can reflect changes in the brain. They recruited 30 adults, all in their mid-70s, who showed no signs of dementia and tested them for biomarkers of preclinical Alzheimer’s disease. As part of the testing, each patient received an optical coherence tomographic angiography examination, which showed the researchers the vasculature of the eye.
The researchers found that nearly half of the participants showed biomarkers of Alzheimer’s disease from the testing, including elevated levels of the Alzheimer’s proteins amyloid or tau. The researchers also found thinning in the retina, which had been previously linked to Alzheimer’s through autopsies. The results of the study were published in the Journal of the American Medical Association Ophthalmology.
Close to 50 million people around the globe are living with dementia, of which Alzheimer’s disease is the most common form. The neurodegenerative disease affects 5.7 million people in America. While brain damage from Alzheimer’s can begin up to two decades before signs of memory loss appear, once the condition has taken hold, there is no cure.
Some of the symptoms of Alzheimer’s disease are reversible and treatable with drug interventions if the condition is detected early enough. Unfortunately, there is currently no one reliable biological test for the disease. The diagnostic methods currently in use, such as a cerebrospinal fluid test, are invasive and expensive. An effective eye test could give patients and doctors similar information in a matter of minutes at a fraction of the cost.