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Study of the retina and optic nerve microvascular bed using optical coherence tomography-angiography in post-COVID-19 patients

Introduction. Signs of angioretinopathy are revealed in 7–27.7 % of post-COVID-19 patients. Optical coherence tomographyangiography (OCT-A) allows performing life-time evaluation of structural and microvascular retinal changes in patients after the new coronavirus infection. Aim. To investigate and to compare main microcirculatory parameters of capillary retinal and optic nerve plexuses using OCT-A in patients after COVID-19 of different severity degree. Materials and methods. The main group consisted of 54 people (108 eyes), who recovered from COVID-19 during 3 preceding months. According to the COVID-19 course severity degree, patients were divided into 3 sub-groups. 22 healthy volunteers (44 eyes) were included in the control group. All patients underwent OCT-A. In the angiography regimen, entire vascular density (VD) and that of every sector in the limits of superficial (SCP) and deep (DCP) capillary plexuses, radial peripapillary capillaries (RPC), and in the foveal avascular zone (FAZ). Results. All over parameters investigated no significant differences between control group patients and those of the sub-group with mild COVID-19 course. In patients with moderately severe infectious process course a significant decrease in VD SCP (P<0.01), as well as decrease in VD RPC (P<0.01). In patients with severe and critically severe disease course there was an decrease of VD DCP in the foveal area (P=0.016) and VD FAZ (P<0.01). VD indices correlations with thickness of retinal layers, in which these vascular plexuses are located. In any of the groups, there was no statistically significant enlargement of the FAZ area and no structural optic disc changes. Conclusion. In post-COVID-19 patients, there are signs of capillary blood flow reduction in retinal SCP and RPC, which is proportional to the prior infection severity degree. Associated to COVID-19 microangiopathy is a significant ophthalmologic sign of the new coronavirus infection. Microvascular changes of the retina could play a role of of a new biomarker reflecting the severity degree of the entire vascular system impairment in COVID-19.