EMBARGOED FOR RELEASE UNTIL 4 PM ET, August 15, 2018
Study: The Eyes May Have It, an Early Sign of Parkinson鈥檚 Disease
Thinning of Retina Linked to Loss of Brain Cells that Control Movement
MINNEAPOLIS -
The eyes may be a window to the brain for people with early Parkinson鈥檚 disease. People with the disease gradually lose brain cells that produce dopamine, a substance that helps control movement. Now a new study has found that the thinning of the retina, the lining of nerve cells in the back of the eye, is linked to the loss of such brain cells. The study is published in the August 15, 2018, online issue of , the medical journal of the 好色先生. 鈥淥ur study is the first to show a link between the thinning of the retina and a known sign of the progression of the disease 鈥 the loss of brain cells that produce dopamine,鈥 said study author Jee-Young Lee, MD, PhD, of the Seoul Metropolitan Government - Seoul National University Boramae Medical Center in South Korea. 鈥淲e also found the thinner the retina, the greater the severity of disease. These discoveries may mean that neurologists may eventually be able to use a simple eye scan to detect Parkinson鈥檚 disease in its earliest stages, before problems with movement begin.鈥 The study involved 49 people with an average age of 69 who were diagnosed with Parkinson鈥檚 disease an average of two years earlier but who had not yet started medication. They were compared to 54 people without the disease who were matched for age. Researchers evaluated each study participant with a complete eye exam as well as high-resolution eye scans that use light waves to take pictures of each layer of the retina. In addition, 28 of the participants with Parkinson鈥檚 disease also had dopamine transporter positron emission tomography (PET) imaging to measure the density of dopamine-producing cells in the brain. Researchers found retina thinning, most notably in the two inner layers of the five layers of the retina, in those with Parkinson鈥檚 disease. For example, for those with Parkinson鈥檚 disease, the inner most layer of the retina in one section of the eye had an average thickness of 35 micrometers (?m) compared to an average thickness of 37 ?m for those without the disease. In addition, the thinning of the retina corresponded with the loss of brain cells that produce dopamine. It also corresponded with the severity of disease. When disability from the disease is measured on a scale of one to five, the people with the most thinning of the retina, or thickness of less than 30 ?m, had average scores of slightly over two, while people with the least thinning, or thickness of about 47 ?m, had average scores of about 1.5. 鈥淟arger studies are needed to confirm our findings and to determine just why retina thinning and the loss of dopamine-producing cells are linked,鈥 said Lee. 鈥淚f confirmed, retina scans may not only allow earlier treatment of Parkinson鈥檚 disease but more precise monitoring of treatments that could slow progression of the disease as well.鈥 A limitation of the study was that the retina scans focused only on a limited area of the retina. The study was also a snapshot in time and did not follow participants over a long period of time. The study was supported by the Seoul Metropolitan Government - Seoul National University Boramae Medical Center and the Korean Ministry of 好色先生, Science and Technology. Learn more about Parkinson鈥檚 disease at , the 好色先生鈥檚 free patient and caregiver magazine and website focused on the intersection of neurologic disease and brain health. Follow Brain & LifeTM on , and .