Retinal tissue and microvasculature loss in COVID-19 infection

Abstract

Purpose : Post-COVID-19 infection sequelae include neurological, pulmonary, and other microvascular changes. Several reports have noted retinal findings, but these are largely anecdotal and may be due to the underlying conditions in people who developed severe COVID infections like diabetes and cardiovascular disease. Our goal was to determine if COVID caused retinal vascular change in patients without underlying conditions.

Methods : Participants were divided into three subgroups; Severe cases requiring intensive care unit admission, mild cases who received out-patient care, and normal controls who had not been infected by COVID-19. Patients who had primary or secondary hypertension, diabetes mellitus, hematologic disorders, any cancer, and any cardiovascular or respiratory disease that developed before the diagnosis of COVID-19 infection were excluded. Participants underwent comprehensive ophthalmologic examination and imaging for retinal thickness and volume measurements obtained from spectral-domain optical coherence tomography (SD-OCT) and vessel density using OCTA.

Results : Sixty-one eyes from 31 individuals were studied: 11 were classified as normal, 13 as mild, and 7 as severe COVID-19. Retinal volume was significantly decreased in the outer 3 mm of the macula in the severe COVID-19 group (0.191 mm²) compared to normal (0.199 mm²) and mild COVID-19 group (0.193 mm²) (p=0.02). Total retinal vessel density was significantly lower in the severe COVID-19 (24.2 least square mean) group compared to the normal (26.28) and mild (26.18) COVID-19 groups (p=0.004 and 0.0057, respectively). Looking at vessel segmentation, the intermediate and deep capillary plexus densities in the severe COVID-19 group were significantly lower compared to normal and mild COVID-19 groups (p<0.05).

Conclusions : Patients who recovered from severe COVID-19 after hospitalization (without underlying conditions) showed significant macular tissue loss, including inner retinal volume and vessel density, potentially due to vessel loss associated with this vasculo-tropic virus. Retinal volume and vessel density loss of this magnitude may not cause significant visual symptoms; however, this may serve as a biomarker for severe COVID or long COVID damage to the brain and other organs. Close monitoring and surveillance of patients who recovered from COVID-19 should be considered to assess for long-term sequela affecting the retina using this non-invasive imaging modality.

This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.