Persistent Retinal Microvascular Impairment in COVID-19 Bilateral Pneumonia at 6-Months Follow-Up Assessed by Optical Coherence Tomography Angiography.

The purpose of this study was to evaluate the long-term evolution of retinal changes in COVID-19 patients with bilateral pneumonia. A total of 17 COVID-19 patients underwent retinal imaging 6 months after hospital discharge with structural optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA). The parafoveal retinal nerve fiber layer (RNFL) and ganglion cell layer (GCL) were significantly thinner in COVID-19 patients at 6 months compared to 0 months (p = <0.001 in both cases). In the optic nerve analysis, a significantly thinner RNFL was observed (p = 0.006) but persisted significantly thickened, compared to controls (p = 0.02). The vascular density (VD) at 6 months persisted significantly decreased when compared to the control group, and no significant differences were found with the 0 months evaluation; in addition, when analyzed separately, women showed a worsening in the VD. Moreover, a significantly greater foveal area zone (FAZ) (p = 0.003) was observed in COVID-19 patients at 6 months, compared to 0 months. The cotton wool spots (CWSs) observed at baseline were no longer present at 6 months, except for one patient that developed new ones. This study demonstrates that some of the previously known microvascular alterations resulting from COVID-19, persist over time and are still evident 6 months after hospital discharge in patients who have suffered from bilateral pneumonia.