Alzheimer’s Disease is a disease that is arguably more scary than cancer or cataracts. As bad as it is to get cancer or cataracts, there are treatments available with high success rates for both diseases. While there are drug therapies available for those with Alzheimer’s, most of them only work in the early to moderate stages of the disease.
Like most diseases, the earlier Alzheimer’s is detected, the sooner treatments can begin. Yet, unlike most diseases, there is no blood test or biopsy to definitively diagnose Alzheimer’s Disease. Research done at the University of Minnesota Center for Drug Design saw that both mice and people with early stages of Alzheimer’s Disease had clumps of a protein called A-beta on the retina. These proteins scatter light differently than other kinds of cells. A special camera, which was developed for this study, was able to detect these proteins. Over time the A-beta grows and get deposited in the brain as plaque and Alzheimer’s Disease develops. Researchers believe that this can be used to detect the disease at its earliest stages – before any memory or behavioral changes are noticeable.
Another study involving eyes and Alzheimer’s was done in the UK. This study investigated the retina and it was found that persons with thinner retinas were more likely to have problems with memory and reasoning. Researchers looked at the retinal nerve fibre layer (RNFL) of people between the ages of 40 and 69 by using optical coherence tomography (OCT). Participants were tested on memory, reaction time and reasoning and those with the thinnest RNFL were more likely to fail one or more of the tests. In addition, these persons who have a thin RNFL were more likely to score worse in the follow up tests that were given three years later.
One of the researchers in the UK study, Paul Foster, from the University College London Institute of Ophthalmology, said that OCT tests can be used to identify those at high risk of developing Alzheimer’s, so they can start treatments sooner. “(By) targeting people in the earlier stages,” said Foster, “It should be possible to design better clinical trials for treatments that make a real difference and improve people’s lives.”
Both of these studies show that the retina is a possible bellwether for Alzheimer’s. The promise of low cost and non-invasive ways to screen for the disease, like OCT, is encouraging. It has been said that eyes are the window of the soul. Now it looks like they can be a window for Alzheimer’s diagnosis and monitoring.