Parkinson’s disease is a brain disorder that slowly affects movement, often causing tremors, stiffness, and problems with balance. It usually shows up in people over 60 and is often only diagnosed after noticeable symptoms appear.
But by then, the brain cells involved have already been damaged beyond repair. That’s why scientists have been searching for a way to detect Parkinson’s much earlier—before major symptoms show up.
A new study from researchers at Université Laval in Québec, Canada, suggests that a simple eye exam could help.
The study, published in the journal Neurobiology of Disease, found that people with early-stage Parkinson’s disease have unusual responses to light in their retinas—the thin layer of tissue at the back of the eye that detects light. These responses were different from those of healthy people.
Professor Martin Lévesque, who led the study, explained why this finding is important. The retina is actually part of the central nervous system, which means it’s closely connected to the brain.
Looking at how the retina responds to light could give doctors clues about what’s going on in the brain—without needing surgery or complex scans. Since the test involves only placing a small electrode under the eye and using flashes of light, it’s simple, non-invasive, and safe.
The research team tested 20 people who had been diagnosed with Parkinson’s disease within the past five years. They compared them with a group of healthy people of the same age. The scientists showed all participants flashes of light with different colors, brightness levels, and speeds.
Then they measured how their retinas reacted. The results were clear: the people with Parkinson’s had a different pattern of response compared to those without the disease.
To better understand what was happening, the team also did experiments with mice. They used genetically modified mice that carry a human protein linked to Parkinson’s. These mice were still young and didn’t show physical signs of the disease yet.
Even so, the scientists saw similar unusual light responses in their retinas. This shows that these eye changes may appear before symptoms like tremors begin, possibly helping doctors detect Parkinson’s very early.
The researchers also looked closely at the retinas of these mice using special imaging techniques. They discovered signs of abnormal protein build-up, especially in the part of the retina responsible for processing light. This supports the idea that early damage in the brain might be seen first in the eyes.
Lévesque believes this kind of eye test could be offered to people as early as age 50. If changes are found, doctors might be able to act before the disease causes serious harm. Early diagnosis would give patients more time to try treatments that may slow the disease or protect their brain cells. The test could also be used to check whether treatments are working over time.
The study was led by PhD student Victoria Soto Linan, with help from several other scientists, including Véronique Rioux, Modesto Peralta III, Nicolas Dupré, and Marc Hébert.
This study offers a promising new way to look for signs of Parkinson’s without needing to wait for symptoms like shaking or stiffness. It highlights the eye as a powerful window into brain health.
The findings from this study are exciting because they suggest a much easier and earlier way to detect Parkinson’s disease. Right now, diagnosis often happens late, when brain damage has already taken place. But this research shows that simple light tests on the eye might catch the disease before that.
The study is strong because it includes both human and animal testing, showing that the retina can reflect early changes in the nervous system linked to Parkinson’s. It also suggests that these changes can be spotted before movement symptoms even begin.
If this research is confirmed by larger studies, it could lead to a major shift in how Parkinson’s is diagnosed and treated. A routine eye test could become an important tool in checking brain health and catching serious diseases early—when they’re much easier to manage.
If you care about Parkinson’s disease, please read studies that Vitamin B may slow down cognitive decline, and Mediterranean diet could help lower risk of Parkinson’s.
For more health information, please see recent studies about how wheat gluten might be influencing our brain health, and Olive oil: a daily dose for better brain health..
The research findings can be found in Neurobiology of Disease.
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