As part of an eye exam in the next few years a new test for Alzheimer’s disease may be available. New research points to a special picture of the eye as having the potential to diagnose Alzheimer’s disease 10-15 years earlier than is common today.
As an eye doctor, I am always saddened when I see one of my patients slowly declining in cognitive function as a result of Alzheimer’s disease. Each year as they come in, the change can be quite noticeable. More than 5 million Americans have Alzheimer’s. In Alzheimer’s disease a buildup of material called beta-amyloid in the brain gradually impairs cognitive function, memory and eventually even basic bodily functions that regulate heart rate, blood pressure and more.
Compounding the devastating effects of the disease is the difficulty and cost of early diagnosis. Early diagnosis would allow researchers to better test treatments before the disease became advanced to the point where intervention might be too little, too late.
Currently, Alzheimer’s disease is diagnosed primarily by clinical examination using memory tests and questions about how a patient is functioning. But researchers are attempting to devise tools, particularly using biological markers, to improve the detection of early stages of the disease, said David Knopman, a neurologist at Mayo Clinic and a member of the Alzheimer’s Association Medical and Scientific Advisory Council.
There are no treatments currently that can stop the progression, but medications such as Aricept® can slow the disease, making early diagnosis even more important. Also, finding treatments that can stop or reverse the disease depends upon finding patients at the earliest stages.
The eye represents a unique opportunity to find the accumulation of beta-amyloid earlier and more cheaply than current PET scan brain imaging. Amyloid plaques found in the brain are also deposited in the eye. Two company-funded studies found that those deposits can be detected through noninvasive eye-imaging technology and are highly correlated with the amyloid results from brain imaging.
If these studies are confirmed, early diagnosis may become a routine part of annual eye exams allowing diagnosis many years earlier than is currently typical.
One can think of the eye as being like a camera, and the retina is the film in the camera. What makes the retina unique is that it is really a part of the brain. Moreover, it is the only part of the brain that can be directly visualized. Since amyloid deposits are found throughout the brain it stands to reason that they would accumulate in the retina too. CSIRO Australia, the country’s national science agency, and its Sacramento, Calif.-based partner, NeuroVision Imaging LLC, have been studying the retina for ways to detect amyloid. The first 40 patients in a 200-participant study showed that retina changes correlated strongly with amyloid plaque development in the brain. The full study will be completed this year, according to researchers.
A news story about this study can be seen here.
At Spectrum Eyecare, we work continuously to provide the most advanced diagnostic and therapeutic eye care. But we also look at the health of the whole person by performing blood pressure and blood sugar testing. As this technology becomes mainstream, we will be sure to bring this testing to our patients.
Dr. Henahan is a resident of Peachtree City and founder of Spectrum Eyecare. You may reach his office at 770-487-0667 or on the web at SpecEye.com.