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COVID-19 findings show increased microvascular vessel changes in the retina between infected and non-infected patients

Researchers in the Luigi Sacco Hospital, Milan, have reported that important changes in the retina in COVID-19 patients were significantly different compared to non-COVID-19 subjects.  In addition, it appears that retinal changes in the microvasculature showed direct correlation in disease severity and seemed to affect patients early in the disease course.  It is not clear whether the retinal changes were caused by the SARSCoV-2 virus or by the patient’s immune response.  Regardless, the Italian research team stated that “if our data will be confirmed, retinal veins diameter could represent a useful parameter to monitor the inflammatory response and/or the endothelial damage in COVID-19”.   The report of the study was published in the journal EClinicalMedicine, 27 (2020) 100550.


As of November 3rd 2020, the pandemic of Severe Acute Respiratory Syndrome-Coronavirus-2 (SARSCoV-2) has now infected almost 48 million people globally, and caused an estimated 1.2M deaths.  While most infections show mild to moderate symptoms, approximately 20% of patients with a diagnosis may require hospital admission, and of those, an estimate of 16% of patients require intensive care.  Some researchers have suggested that the cytokine storm may be in part due to an underlying mechanism leading to acute respiratory distress syndrome (ARDS).  Blood hypercoagulability has also been reported and further several studies have shown diffuse endothelial damage in COVID-19 patients and thromboembolic events.  In a current study, non-invasive nature of fundus examination has been proposed that the screening of patients with SARS-CoV-2 infection, potentially useful to assess the possible correlations with the clinical parameters.


54 COVID-19 patients and 133 unexposed subjects were recruited in a study entitled: “ScrEening the Retina in Patients wIth COVID-19” (SERPICO-19).  The study was measured by the mean artery diameter (MAD) and the mean vein diameter (MVD).  MAD and MVD were higher in COVID-19 patients compared to unexposed subjects (98.3 ± 15.3 µm vs 91.9 ± 11.7 µm, p = 0.006 and 138.5 ± 21.5 µm vs 123.2 ± 13.0 µm, p<0.0001, respectively).  In addition, multiple regression accounting for covariates MVD was positively associated with COVID-19 both in severe (coefficient 30.3, CI 95% 18.1 – 42.4) and non-severe (coefficient 10.3, CI 95% 1.6 – 19.0) cases compared to unexposed subjects. In COVID-19 patients MVD was negatively correlated with the time from symptoms onset (coefficient -1.0, CI 95% -1.89 to – 0.20) and positively correlated with disease severity (coefficient 22.0, CI 95% 5.2 – 38.9). In summary, retinal veins diameter seems directly correlated with the disease severity.