The latest clue to early detection of Parkinson’s disease may lie in the eye. A small study from South Korea published recently in the journal Neurology found that people with early-stage Parkinson’s show a thinning of their retinas, a layer of light-sensitive nerve cells at the back of the eye.

“Our study is the first to show a link between the thinning of the retina and a known sign of the progression of the disease — the loss of brain cells that produce dopamine,” said study author Jee-Young Lee, MD, PhD, of the Seoul Metropolitan Government — Seoul National University Boramae Medical Center, in a press release.” 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.”

The study involved 49 people diagnosed with Parkinson’s an average of two years ago and 54 control volunteers.

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’s disease also had dopamine transporter positron emission tomography (PET) imaging to measure the density of dopamine-producing cells in the brain.

The study found that people with Parkinson’s had more retinal thinning. Also, the scientists found that the thinner the retina, the more dopamine loss seen on a brain scan (DaTscan) and the greater one’s physical disability.

Scientists are looking for tests to diagnose Parkinson’s early so they can study the disease in its beginning stages, learn more about its causes, and test therapies to stop its progression.

The Michael J. Fox Foundation has funded several studies looking at the eye for early signs of disease. Some have measured structural changes in the retina. Others are looking at levels of the Parkinson’s-associated protein alpha-synuclein in the eye.

Article Source:  The Michael J. Fox Foundation for Parkinson’s research