Early detection and timely treatment can reduce the severity and slow the progression of neurodegenerative diseases such as Parkinson's. In a new study, researchers claim retinal imaging can diagnose Parkinson's disease seven years before symptoms appear.

In the latest study, published in the journal Neurology, researchers from University College London and Moorfields Eye Hospital in the U.K. identified markers of Parkinson's in eye scans that could be analyzed using artificial intelligence.

"This is the first time anyone has shown these findings several years before diagnosis, and these results were made possible by the largest study to date on retinal imaging in Parkinson's disease," the researchers said in a news release.

"Oculomics" is an emerging field of research that uses eye scans to understand the biomarkers of diseases. Earlier studies have shown that retinal imaging can help in detecting neurodegenerative conditions, including Alzheimer's, multiple sclerosis and schizophrenia.

In the latest study, researchers used the AlzEye database – a large database of retinal images and associated clinical data. The analysis was repeated using the UK Biobank database of healthy volunteers.

The team recorded detailed retinal images of the participants using an Optical Coherence Tomography scanner that is normally used by opticians during eye tests. These images were then evaluated using AI to estimate the changes in a "specific area" of the retina that indicates Parkinson's disease.

"One of the unique things about Parkinson's is that it affects a particular type of cell in the brain, cells that use a chemical called dopamine. We actually have cells that use dopamine in the eye as well and most of them are located in a specific layer here of the retina," said Dr. Siegfried Wagner, the lead author of the latest study.

"I continue to be amazed by what we can discover through eye scans. While we are not yet ready to predict whether an individual will develop Parkinson's, we hope that this method could soon become a pre-screening tool for people at risk of the disease," Wagner added.

Researchers are hopeful the findings would pave the way for a non-invasive and low-cost diagnostic tool for diagnosing Parkinson's in the future.

"Finding signs of a number of diseases before symptoms emerge means that, in the future, people could have the time to make lifestyle changes to prevent some conditions from arising, and clinicians could delay the onset and impact of life-changing neurodegenerative disorders," Wagner said.