Want to know more about your future risk of developing heart or lung problems? Your retinal thickness might hold important clues.
Using data from 44,828 participants, an international research team found that having thinner retinas was correlated with an increased risk of ocular, neurological and cardiovascular diseases. Most notably, this is the first study to find that a thinner retina increases someone’s risk of developing a lung condition like bronchitis or emphysema later in life.
The data came from the UK Biobank, an enormous medical database that contains anonymous details about the health and genetics of around half a million people in the UK. The retinal images included in the data were captured using a non-invasive procedure called optical coherence tomography. Ophthalmologists routinely use this technique to determine a patient’s risk for various eye conditions, including macular degeneration and glaucoma. The procedure captures information about the retina – which is usually 0.5 millimetres thick – and its internal layers.
Nazlee Zebardast at Harvard Medical School, one of the study authors, hopes the study will eventually expand how optical coherence tomography is used. Beyond simply giving details about the eyes, she would like to see it become a tool for providing future health information about the whole body.
“We have patients coming to our eye clinic all the time,” she says. “Wouldn’t it be great if we could tell from someone’s retinal image, ‘you look like you might have a high risk of sleep apnoea’, or ‘you might have a high risk of developing diabetes’?”
While exciting, this technology is still “a long way off” from immediate clinical application, says Anthony Khawaja at University College London. Researchers are still unsure why retinal biology might correspond to systemic health, or what kind of mechanism might be driving the associations seen in this study and others. What’s more, Zederbast and her colleagues point out in the paper that a lack of genetic diversity within the UK Biobank sample limits the universal applicability of their conclusions: 94 per cent of the people who contributed their data to the database have white European ancestry.
Still, Zebardast is optimistic about the study’s implications. She says researchers will first need to carry out prospective studies, tracking people for years to see whether a thinner or thicker retina actually does correspond to an elevated risk of developing conditions like heart disease or pneumonia. But if such research confirms these hypotheses, then retinal imaging could emerge as a useful and non-invasive method for routine health screening.