London scientists have identified markers that indicate the presence of Parkinson's in patients seven years before diagnosis, paving the way for people to be screened for the disease in the future.
Researchers from Moorfields Eye Hospital and the UCL Institute of Ophthalmology analysed data from patients who received an optical coherence tomography (OCT) scan, which is widely used in eye clinics and high-street opticians.
In less than a minute, an OCT scan produces a cross-section of the retina (the back of the eye) in vivid detail – down to a thousandth of a millimetre.
The researchers analysed figures from a dataset named AlzEye, which links eye data from Moorfields with NHS hospital admissions for 353,157 patients over a 10-year period. This analysis was then repeated on separate figures from the UK's wider Biobank database.
Artificial intelligence enabled the team to identify subtle markers of Parkinson's disease in the datasets in a fraction of the time that it would take a human team.
Their analysis uncovered differences in the INL (inner nuclear layer) of the retina in Parkinson's patients. A reduced thickness of these layers was associated with an increased risk of developing Parkinson’s disease, beyond that conferred by other factors or comorbidities.
Post-mortem examination of patients with Parkinson’s disease has previously revealed differences in the INL of the retina.
Parkinson's is a condition which causes progressive damage to the brain over a number of years. There are more than 10 million people worldwide living with the disease, according to the Parkinson's Foundation.
The use of data from eye scans has previously revealed signs of other neurodegenerative conditions, including Alzheimer's, multiple sclerosis and, most recently, schizophrenia.
Eye scans and eye data have also been able to reveal a propensity to high blood pressure, cardiovascular disease and diabetes.
Siegfried Wagner, clinical research fellow at Moorfields Eye Hospital and a researcher at the UCL Institute of Ophthalmology, said: “I continue to be amazed by what we can discover through eye scans. While we are not yet ready to predict whether an individual will develop Parkinson’s, we hope that this method could soon become a pre-screening tool for people at risk of disease.
"Finding signs of a number of diseases before symptoms emerge means that, in the future, people could have the time to make lifestyle changes to prevent some conditions arising, and clinicians could delay the onset and impact of lifechanging neurodegenerative disorders.”
Their research adds to an emerging field of research known as “oculomics”, which is investigating the ways which changes in the eye could signal future disease.
Louisa Wickham, Moorfields’ medical director, said: “Increasing imaging across a wider population will have a huge impact on public health in the future, and will eventually lead to predictive analysis. OCT scans are more scalable, non-invasive, lower cost and quicker than brain scans for this purpose.”
The study was published on Monday in the American journal Neurology. It involved collaboration between researchers at Moorfields Eye Hospital, University Hospital Birmingham, Great Ormond Street Hospital (GOSH), Oxford University Hospital, University College Hospital London and the UCL Great Ormond Street Institute of Child Health.
