Persistent reduction of retinal microvascular vessel density in patients with moderate and severe COVID-19 disease

Abstract

ObjectiveThis study aims to analyse the possible recovery or worsening in retinal microvasculature after 8 months in a previously studied COVID-19 cohort.Methods and analysisA cross-sectional case–control study and a prospective longitudinal cohort study. Participants were the subjects of our previous study who re-enrolled for a new examination including a fundus photograph (retinography), an optical coherence tomography (OCT) scan and an OCT angiography. COVID-19 diagnosed patients were divided into three groups: group 1: mild disease, asymptomatic/paucisymptomatic subjects who received outpatient care; group 2: moderate disease and group 3: severe disease, both of which required hospital admission because of pneumonia. Statistical analyses were performed using SPSS software (V.23.0). Cross-sectional intergroup differences were analysed by means of analysis of variance for normally distributed variables and the Kruskal-Wallis test for non-normally distributed ones. In reference to the prospective part of the study (intragroup differences, baseline with 8-month comparison), a paired t-test was used for normally distributed data and Wilcoxon signed ranks sum for non-normally distributed data.ResultsThe fovea-centered superficial and deep vascular densities were significantly diminished in severe cases compared with mild cases (p=0.004; p=0.003, respectively, for superficial and deep) and to controls (p=0.014; p=0.010), also in moderate cases to mild group (p=0.004; p=0.003) and to controls (p=0.012; p=0.024). In the longitudinal study, no significant statistical differences were found between baseline and 8-month follow-up vessel density values.ConclusionWe demonstrated persistent reduction in the central vascular area over time in patients with moderate and severe COVID-19.

The Comparison of Retinal Microvascular Findings in Acute COVID-19 and 1-Year after Hospital Discharge Assessed with Multimodal Imaging—A Prospective Longitudinal Cohort Study

“…Notably, we also found no differences when comparing acute COVID-19 patients with a healthy control group [ 16 ]. While some of the previous studies are in line with our results [ 17 , 18 ], a decreased VD and an enlarged FAZ area were reported [ 18 , 19 , 20 , 21 , 46 ] and the observed differences were either stable [ 47 ] or more pronounced after a 3–8 month follow-up [ 21 , 21 , 22 , 23 , 23 ]. However, none of the studies reported any macroscopic changes on OCTA images, suggestive of either thromboembolisms or ischemia.…”

Use of Imaging Technology to Assess the Effect of COVID-19 on Retinal Tissues: A Systematic Review

“…Their control cohort consisted of 27 age- and sex-matched patients. Garcia et al [ 47 ] re-imaged the same cohort of patients imaged in Zapata et al's study 8 months after the baseline visit. This study provides evidence of lower central retinal VD persistence in patients with moderate and severe COVID-19 pneumonia.…”

Update on coronavirus disease 2019: Ophthalmic Manifestations and Adverse Reactions to Vaccination

“…46 Differences in vascular density between patients with COVID-19 and healthy controls have been observed, and these may last for months postinfection. 47 Some research shows reduced vascular density in both superficial and deep capillary plexuses (DCP) at foveal and parafoveal levels among patients with COVID-19, whereas other studies find these changes mainly in peripheral areas. Some research also shows an enlarged foveal avascular zone and increased choroidal capillary plexus blood flow, likely due to hypoxia and inflammation-induced vasodilation.…”

“…These changes may be attributed to the infection and systemic conditions like hypertension or medical treatments 46 . Differences in vascular density between patients with COVID-19 and healthy controls have been observed, and these may last for months postinfection 47 . Some research shows reduced vascular density in both superficial and deep capillary plexuses (DCP) at foveal and parafoveal levels among patients with COVID-19, whereas other studies find these changes mainly in peripheral areas.…”