A study conducted by Mass Eye and Ear, the Broad Institute at MIT, and Harvard Medical School has demonstrated links between the thinning of different retinal layers and an increased risk of disease. The work used OCT retinal images and genetic data from thousands of UK Biobank participants and could serve to advance the use of OCT to predict ocular disease and inspire further research on disease prediction beyond the eye. The researchers analyzed data from more than 44,000 UK Biobank participants who underwent OCT retinal imaging and genotyping in 2010. The participants were subsequently followed for an average of 10 years. The team performed a cross-phenotype analysis using OCT images from the UK Biobank and identified associations between retinal layer thickness and ocular, neuropsychiatric, and cardiometabolic diseases experienced by the participants during the 10-year follow-up period. (Left) Senior author Nazlee Zebardast, director of Glaucoma Imaging at Mass Eye and Ear and an assistant professor of ophthalmology at Harvard Medical School. (Right) Saman Doroodgar Jorshery (left) and Seyedeh Maryam Zekavat examine data and OCT images of retinal thickness. Courtesy of Mass Eye and Ear. The retinal images from the UK Biobank also helped the researchers gain insight into the genes and biological pathways that determine retinal health. The researchers performed genome-wide association studies, identifying inherited genetic markers that influence retinal layer thickness. They conducted a comparative analysis of phenome- and genome-wide associations to identify potential links between retinal layer thickness and ocular and systemic conditions. Through genome-wide associations, the researchers identified 259 different loci linked to retinal layer thickness. “Each layer of the retina is made up of different types of cells with diverse structures and functions, and we show that the thicknesses of these different layers are associated with different conditions,” said senior author Nazlee Zebardast, director of Glaucoma Imaging at Mass Eye and Ear and an assistant professor of ophthalmology at Harvard Medical School. The researchers observed a consistency between epidemiologic and genetic associations that indicated links between a thinner retinal nerve fiber layer and glaucoma, and between a thinner photoreceptor segment and age-related macular degeneration. They also linked poor cardiometabolic and pulmonary function with a thinner photoreceptor segment. “We’ve come to realize recently that there is a lot more information that we can get from our retina images than we thought was possible,” Zebardast said. Previous studies have revealed links between retinal health and aging, cardiometabolic diseases such as diabetes and hypertension, and neurological diseases such as dementia, stroke, and multiple sclerosis. Unlike earlier studies that focused on the genes associated with overall retinal health, the Mass Eye and Ear study addressed the role of the different cell layers that comprise the retina, in addition to investigating the genes that affect retinal health. Although retinal OCT imaging is already a standard clinical procedure in ophthalmology, the researchers believe that it could be put to broader use. Further work to establish the connection between ocular and cardiometabolic health will provide more insight into the value of retinal OCT imaging as a clinical tool. “Patients come to us for their eye health, but what if we could tell them more than that,” Zebardast said. “What if we could use someone’s retinal images to tell them, ‘You seem to have a high risk of having high blood pressure, maybe you should get screened, or maybe your primary care doctor should know about that.’” The study is part of an ongoing effort at Mass Eye and Ear to identify genetic markers of glaucoma and other ocular diseases. The research was published in Science Translational Medicine (www.doi.org/10.1126/scitranslmed.adg4517).