Parkinson's Disease Could Be Predicted With Eye Scan, Study Suggests

They say the eyes are the window to the soul—but they could also reveal our risk of developing Parkinson's disease according to a small study.

Every year, around 50,000 people in the U.S. are diagnosed with the neurodegenerative condition. Currently, Parkinson's disease is generally not picked up until symptomslike tremors, stiffness of the limbs and trunk, slow movement and a loss of balance and coordination—become obvious, according to the Department of Health.

The team behind the research, published in the journal Neurology, believe thinning of the retina could be an early sign of brain cells dying away.

For the small study, the researchers recruited 49 people with an average age of 69 who had been diagnosed with Parkinson's disease an average of two years prior. None of the patients were taking medication for the condition. The team also enrolled a group of 54 people without the disease who were matched for age.

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Each participant underwent an eye test and high-resolution eye scan where light waves captured an image of each layer of the retina. Of the total participants with Parkinson's disease, the researchers used a special imaging technique on 28 to map the density of dopamine-producing cells in the brain.

Those with the neurodegenerative disease were found to have thinner retinas, particularly in the two inner layers of the five layers of the tissue. This was also associated with the depletion of brain cells that create dopamine, which in turn appeared to correspond with the severity of an participants' symptoms.

Dr. Jee-Young Lee, of the Seoul National University Boramae Medical Center, said in a statement this is the first study to show a link between the retina wearing away and the onset of Parkinson's.

Thinning retinas were linked to Parkinson's disease in a study. Getty Images

"These discoveries may mean that neurologists may eventually be able to use a simple eye scan to detect Parkinson's disease in its earliest stages, before problems with movement begin."

As the study was small, however, the researchers acknowledged a larger project is needed to confirm if a thinning retina and the loss of dopamine-producing cells are linked.

Other downfalls included the fact the scans honed in on a limited part of the retina, and the participants were not followed up over a long period of time.

"If confirmed, retina scans may not only allow earlier treatment of Parkinson's disease but more precise monitoring of treatments that could slow progression of the disease as well," said Lee.