According to the Alzheimer’s Association, there are currently about 5.8 million people with Alzheimer’s disease in the United States, making it the sixth leading cause of death. It’s the most common form of dementia with up to 80 percent of all diagnosed cases. People who have Alzheimer’s disease typically have problems with memory and thinking, along with behavior and mood issues. And as the disease progresses, these symptoms get more severe.
While scientists have not determined precisely what triggers the onset of Alzheimer’s, research shows that the condition is caused by the death and degeneration of brain cells. In Alzheimer’s patients, a protein known as beta-amyloid accumulates in the brain and forms plaques, disrupting communication between neurons. This, in turn, sets the immune response into motion, leading to inflammation that effectively kills brain cells.
Currently, the only way to diagnose Alzheimer’s disease is with highly invasive and expensive tests, such as PET scans, brain imaging, and lumbar punctures, to test the patient’s spinal fluid. However, recent scientific research shows that risk for the disease may be diagnosed through a retina scan, which is easier and less invasive to perform.
It’s estimated that Alzheimer’s related plaques can start to accumulate around 20 years before there are any symptoms. In fact, brain damage and the loss of brain cells can occur years before the patient experiences any cognitive decline or memory loss. However, the plaque is very difficult to see, which is why large-scale screening has traditionally been impractical. With a retina scan, assuming further research confirms that it’s a viable option, that type of screening would be possible.
The retina contains a dense network of blood vessels, but there’s a small area in the center of the retina – an area that is responsible for our most precise vision – with no blood vessels. Research has found that, because the retina and optic nerve are so thoroughly interconnected with the central nervous system, the buildup of beta-amyloid plaques affects this area of the retina by making it bigger, as well as working its way into the retina.
During a screening, the doctor would scan the retina through the pupil for the density of these blood vessels and look for an enlarged area without them. These blood vessels currently can’t be detected with a regular retina scan, but new technology is able to take high-resolution images within just a few minutes. Another new scanning technique uses auto-fluorescent imaging of the retina, which is able to detect the beta-amyloid proteins. The hope is that further research will establish that the retina scan is a reliable marker for Alzheimer’s, which would then justify more invasive testing. If that’s the case, Alzheimer’s could be detected much earlier, before memory and cognitive function loss start to occur.
While Alzheimer’s disease is not curable, once it’s diagnosed, there are ways to lessen or delay the cognitive symptoms. With this new test, regular screenings could begin when the patients in their forties or fifties, which would allow treatment to begin before symptoms start to present themselves. And that would drastically improve quality of life for patients and their families.