You know how you would go to your doctor's office and s/he would use an ophthalmoscope to conduct an eye exam? Well, if things pan out well, a new type of eye exam may do more than just evaluate your eye health.
A group of researchers at the University of Minnesota found that it might be possible to diagnose Alzheimer's disease years before its effects can be seen in patients, opening up the possibility of testing drugs for treating or preventing the disease's development.
The team detailed exactly how it reached this conclusion in a study published in the journal Investigative Ophthalmology and Visual Science. To start, the researchers designed a spectral imaging system using a machine vision camera and tunable wavelength system to measure the reflection of light off the retinas of mice.
The researchers then took two different types of mice: mice with Alzheimer's and mice without the disease. Upon testing the amount of light reflected off the retinas of each type of mouse, they came to a simple conclusion: those with Alzheimers had a reduced amount of light reflecting off their retinas.
So, why is this significant? To date, there is no definitive test for Alzheimer's disease, which is instead diagnosed based on a set of symptoms. The one thing that scientists have determined over the years, however, is that amyloid plaque build-up in the brain is tied to progressive decline of memory and cognitive skills typical of the disease.
Yet, even with this knowledge, there was one approach that scientists didn't seem to take toward dealing with Alzheimer's: the eyes. Due to both being part of the central nervous system, Alzheimer's has a similar effect on both the brain and the retinas. The core difference between the two, however, is that, due to the accessibility of the retinas, changes there are easier to detect.
Also, in the case of Alzheimer's, by recognizing a decrease in the light reflection — an indicator of amyloid buildup in the retinas, and by extension, the brain — the disease, in theory, could be detectable long before the typical memory and cognitive declines associated with the disease are apparent.
"We saw changes in the retinas of Alzheimer's mice before the typical age at which neurological signs are observed," Dr. Swati More, an assistant professor at the Center for Drug Design, said in a press release. "The results are close to our best-case scenario for outcomes of this project."
While this is all in theory for the time being, the team is already working on making this potentially groundbreaking treatment a reality. It has plans to launch a phase 1 clinical trial of the retina imaging device with humans this month, where the hope is to find an inexpensive diagnosis method that could lead to actual treatment of the condition, rather than just managing its symptoms.
Even with this new knowledge, there is still one important caveat: as Dr. Robert Vince, director of the Center for Drug Design, notes, in order to treat the disease, therapy would need to be administered before patients have signs of the disease — entirely new territory for doctors and researchers alike, since, up until now, the possibility for testing the efficacy of a treatment was impossible due to there being no diagnostic tool to measure its effects.
Despite that, this is definitely a step up from the options available before, finally allowing doctors to appropriately address a disease that was once believed to be undetectable until it was too late.
