By Linda Conlin, Pro to Pro Managing Editor

We know that the eye can reveal clues to not only eye disease, but many systemic diseases, such as hypertension, diabetes, MS, Alzheimer’s, and more. The use of data from eye scans is known as oculomics. Oculomics analyzes imaging to identify the specific ophthalmic biomarkers of systemic diseases with the goal of developing rapid, noninvasive, cost-effective methods to screen and diagnose systemic diseases and prioritize treatment. Now, researchers at University College, London, found markers that indicate the presence of Parkinson’s disease (PD) in patients on average seven years before clinical presentation by using AI to analyze ocular coherence tomography (OCT) data.

Parkinson's disease is a brain disorder that causes unintended or uncontrollable movements, such as shaking, stiffness, and difficulty with balance and coordination. Signs and symptoms of Parkinson’s disease occur when nerve cells in the basal ganglia, an area of the brain that controls movement, become impaired and/or die. Normally, these neurons, produce an important brain chemical known as dopamine. When the neurons die or become impaired, they produce less dopamine, which causes the movement problems associated with the disease. In the retina, those neurons are known as amacrine cells.

According to a research article published in Neurology®, Retinal Optical Coherence Tomography Features Associated With Incident and Prevalent Parkinson Disease, (Neurology Aug 2023, 10.1212/WNL.0000000000207727; DOI: 10.1212/WNL.00000000002077270) postmortem examinations have found reduced dopamine content in the retinas of people with PD, and researchers sought to find indications of reduced dopamine in living patients through AI analysis of OCT. They analyzed OCT data from two studies for a total of more than 200,000 patients spanning 2006 to 2018. They found that individuals with PD have reduced thickness of two to three layers of the retina several years before other signs and symptoms of the disease presented, compared to the control group, as well as significantly reduced dopamine producing amacrine cells.

OCT is now a routine part of a comprehensive eye examination. It’s a quick and noninvasive procedure that yields images of a highly detailed cross section of the retina down to one-thousandth of a millimeter. Combine that detail with a type of AI known as machine learning, and computers are now able to uncover hidden information about the whole body from these images alone in a fraction of the time it would take a human. Oculomics, the association of ophthalmic biomarkers with systemic health and disease, offers a unique opportunity to further our understanding of eye-body relationships and support the development of diagnostic tools and ability to predict the likely outcome of a disease through non-invasive means.