Retinal findings of COVID-19 patients using Ocular coherence tomography angiography two to three months after infection

• The retina uniquely allows direct, non-invasive investigation of the microvasculature, providing a valuable window into the microvascular changes of diseases • Recovered COVID-19 patients have significantly increased peripapillary (whole image), and macular vessel density (superficial and deep) compared to healthy normal subjects. • Recovered COVID-19 patients have significantly higher peripapillary retinal nerve fiber layer thickness, and inner and total foveal thickness compared to healthy normal subjects. The aim of this study was to evaluate the ocular disorders in COVID-19 patients, two to three months after infection. In this cross-sectional, historically controlled study, fifty-one COVID-19 patients were compared with thirty-seven age, and gender-matched healthy individuals. After complete ophthalmological examination, all participants underwent peripapillary and macular optical coherence tomography, and optical coherence tomography angiography (OCTA) measurements (OptoVue Inc, Freemont, CA, USA). The time between the initial onset of symptoms, and ophthalmologic examination was 63.31±15.21 (40-95 days). Ophthalmic examination of all the recovered COVID-19 patients was within normal range. None of the peripapillary and macular OCTA parameters were significantly different between the two groups with pairwise comparisons, but after adjusting for age, gender, axial length, and signal strength index (SSI), recovered COVID-19 eyes showed a significant increase in peripapillary retinal nerve fiber (RNFL) thickness, superficial, and deep macular vessel densities in parafoveal and perifoveal regions compared with healthy control eyes (p<= 0.05). Inner retinal thickness overall is higher in recovered COVID-19 eyes compared to healthy eyes after adjustment. Patients with moderate-intensity SARS-CoV-2 pneumonia had altered peripapillary and macular vessel density compared to healthy subjects. Further investigation is warranted to analyze the correlation of these changes with disease severity as well as evolution of these changes over time.