Researchers have found what may be a direct link between the diameter of retinal veins and the severity of Covid-19, suggesting measuring retinal veins could form an important part of diagnosis and disease management.
Given that Covid-19 is already associated with microvascular alterations in other areas of the body, and because retinal alterations are commonly seen in patients with viral diseases, a team led by Dr Alessandro Invernizzi, Luigi Sacco Hospital, Milan, Italy, decided to investigate retinal and vasculature changes and assess possible correlations with clinical parameters.
The team’s cross-sectional, single-centre study included 54 confirmed SARS-CoV-2 patients admitted to Luigi Sacco Hospital, while the control group was comprised of 133 hospital and university staff not exposed to the virus. Researchers used fundus photographs to determine the mean diameters of the arteries and veins while considering age, sex, ethnicity, body mass index, smoking/alcohol consumption, hypertension, hyperlipidemia and diabetes.
Findings showed Covid-19 patients’ mean arterial and venous diameters were significantly greater compared to unexposed subjects, while multiple regression analysis confirmed a positive association between the venous diameters and severe Covid-19 and non-severe cases compared with unexposed subjects.
“In summary, we found that Covid-19 can induce important changes at the level of the retina, most of them affecting the retinal vasculature and particularly the veins,” said researchers. “The entity of such changes was correlated directly with the disease severity and seemed to affect patients early in the disease course.”
The team could not determine if the retinal changes resulted from the virus or if they were due to the immune response of the host, however, so recommended further prospective studies to understand retinal changes and their possible applications in the diagnosis and management of Covid-19.
The full results of the Screening the retina in patients with Covid-19 (SERPICO-19) study were published in The Lancet EClinical Medicine.