Optical coherence tomography-based assessment of macular vessel density, retinal layer metrics and sub-foveal choroidal thickness in COVID-19 recovered patients

Abstract

Purpose: The primary objective of the study was to assess the macular retinal vessel density, subfoveal choroidal thickness, and retinal layer metrics by optical coherence tomography angiography (OCTA), enhanced-depth imaging optical coherence tomography (EDI-OCT), and spectral domain optical coherence tomography (SD-OCT), respectively, in recovered COVID-19 patients and its comparison with the same in control subjects. The secondary objective was to evaluate differences in OCTA parameters in relation with the severity of COVID-19 disease and administration of corticosteroids. Methods: A case–control study was performed that included patients who had recovered from COVID-19 and age-matched healthy controls. Complete ocular examination including OCTA, SD-OCT, and EDI-OCT were performed three months following the diagnosis. Results: Three hundred sixty eyes of 180 subjects were enrolled between the two groups. A decreased mean foveal avascular zone area in both superficial capillary plexuses ( P = 0.03) and deep capillary plexuses ( P < 0.01), reduced average ganglion cell layer-inner plexiform layer thickness ( P = 0.04), and increased subfoveal choroidal thickness ( P < 0.001) were observed among cases in comparison to the control group. A significant correlation was found between sectoral macular vessel density in relation to disease severity and a decrease in vessel density with greater severity of the disease. Conclusion: OCTA detected retinal microvascular alterations following SARS-CoV-2 infection in subjects with the absence of any clinical ocular manifestation or systemic thrombotic events. These parameters could be used to help identify patients with a higher incidence of systemic thromboembolism on longer follow-ups and identify the impact of corticosteroids on retinal architecture.

Microvascular Alteration in COVID-19 Documented by Nailfold Capillaroscopy

“…Actually, Özbaş et al worked on a larger number of patients who recovered from SARS-CoV-2 (n = 105) compared with a healthy control group (n = 95) and found no statistically significant difference in the vessel density of the superficial and deep retinal capillary plexus; however, in this study, the patients in the COVID-19 groups presented different severities of the disease [52]. Samendra Karkhur et al clarified this point by analyzing 180 subjects in a case-control study, compared with healthy vs. recovered from SARS-CoV-2 patients, and pointed out a significant lower vessel density in the more severe form of disease; this finding agrees with Sulli and Agabiti's results on nailfold examination [30,35,53]. These results were confirmed by other studies such as the COVID-OCTA study, which was conducted in Turkey on 80 patients who had recently recovered from SARS-CoV-2 infections and an 80-patient matching age and sex control group, confirming the lower vessel density on OCTA in the first group, suggesting the use of OCT and OCTA to monitor early changes in diseases affecting microvessels [54].…”