Researchers at Seoul National University Boramae Hospital demonstrated for the first time in the world the link between structural changes in retinas and in the density of cells that produce dopamine in the brain for Parkinson’s.
Parkinson's disease is the most common degenerative brain disease that occurs after dementia. It is caused by the gradual loss of dopamine-releasing neurons in a specific region of the brain called the “black body” located in the midbrain.
The disease is one of the hardest conditions to diagnose as it is difficult to pinpoint the onset of the illness that occurs mainly in older people and progresses very slowly. Also, as there is no current treatment, finding an early diagnosis method has become an important issue.
The research team, led by Professors Kim Tae-wan of the department of ophthalmology and Lee Jee-young of the department of neurology at the hospital, investigated the relationship between the reduction of dopamine-producing cells in the brain and the reduction of retinal thickness in patients with the early stage of Parkinson's disease.
The team selected 49 Parkinson's disease patients with an average age of 69 who had not yet started treatment. The team then conducted an eye examination and scanned five layers of the patients’ retina, while also measuring the density of cells producing dopamine in the brain via positron emission tomography (PET).
As a result, the researchers found that the participants had a thinner retinal thickness of 35 μm compared to the average retinal thickness of 37 μm in the same age group. Also, the thinning of the retina was consistent with the loss of brain cells producing dopamine and the severity of Parkinson's disease.
“The study found that the thinner the retina is, the severity of the Parkinson's disease increased,” Professor Lee said.
Professor Kim said that the team expects its study will open a new possibility of early diagnosis of Parkinson’s disease by just eye scanning.
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