Some COVID-19 Cases Result in Retinal Vascular Density Decreases, Study Shows

A medical worker takes care of a patient at the Covid-19 department of the Tor Vergata hospital, in Rome, on January 5, 2021. (Photo by Andreas SOLARO / AFP) (Photo by ANDREAS SOLARO/AFP via Getty Images)
Researchers used various imaging technologies to evaluate the foveas of patients following moderate and severe coronavirus-related pneumonia.

Retinal central vascular density (VD) is lower in moderate and severe cases of coronavirus disease 2019 (COVID-19) pneumonia than in patients who are asymptomatic or paucisymptomatic or did not have the infection, researchers found in a case-control study of adults published in the British Journal of Ophthalmology. The researchers sought to observe any retinal capillary changes associated with the prothrombotic and inflammatory state in COVID-19 as there were no previously published studies that assessed the state of retinal vascularization in patients following the disease.

The researchers included patients between 18 years and 55 years old with polymerase chain reaction (PCR)-confirmed COVID-19 infection during the last 3 months since the patient’s enrollment. They excluded patients with known prior ophthalmological records, myopia worse than -6.00 D, diabetes with any sign of retinopathy, active vascular diseases that could lead to retinopathy, such as malignant hypertension, multiple myeloma, or hyperglobulinemia.

The cases were divided into group 1 (24 symptomatic/paucisymptomatic patients who received outpatient care), group 2 (24 patients with moderate disease who required hospital admission but did not develop acute respiratory distress or respiratory failure and had interleukin 6 (IL-6) values less than 40 pg/mL during hospital stay) and group 3 (21 patients with severe disease who developed acute respiratory distress syndrome and were referred for intensive care unit (ICU) admission with IL-6 values above 40 pg/mL at any time during hospital stay). A control group of 27 patients without COVID-19 infection within 4 weeks prior to enrollment and group 1 were randomly selected and matched for age and sex.

All patients responded to a questionnaire on comorbidities, chronic medication and use of alcohol, tobacco, and illicit drugs. The researchers performed a 50° color photograph of the retina posterior pole, an automatically fovea-centered optical coherence tomography (OCT) or OCT angiography, and a macula-centered high-definition OCT (scan radial 12mm) on all patients. 

The researchers found that mean fovea-centered VD was reduced in group 2 (13.37 standard deviation (SD) 4.90) and group 3 (13.63, SD 3.78) compared with group 1 (17.16 (SD 3.48)) and control group (16.92, SD 3.10). The higher central VD in control group and group 1 was statistically significant (control group vs group 2, P =.009; control group vs group 3, P =.026; group 1 vs group 2, P =.006; group 1 vs group 3, P =.017) in ANOVA analysis after Bonferroni correction for multiple measurements.

Female and patients of Latin American origin across all groups also had lower central VD (male 16.81 vs female 14.15; P =.002) (White 15.81 vs Latino 13.25; P =.03).

Limitations of the study included small sample size and delay time between active infection and ophthalmological exam due to non-portable tomography equipment.


Zapata MA, García SB, Sánchez A, et al. Retinal microvascular abnormalities in patients after COVID-19 depending on disease severity. Br J Ophthalmol. Published online December 16, 2020. doi:10.1136/bjophthalmol-2020-317953