Retinal microvascular impairment in COVID-19 patients: A meta-analysis

The coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has led to a global pandemic in an unprecedented time frame. Systemic vascular involvement in COVID-19 has been identified, and SARS-CoV-2 has also been found to cause multiple organ ischemia and posterior ocular segment disease in mammals, raising concerns about the human retinal microvascular involvement in SARS-CoV-2.

To objectively assess the presence of retinal microvascular impairment in COVID-19 patients by optical coherence tomography angiography (OCTA), so as to facilitate the clinical system management of COVID-19 patients.

We searched PubMed, Cochrane Library, EMBASE, Ovid, CBM to collect eligible studies. The main outcomes included the vessel density (VD), area or perimeter of foveal avascular zone (FAZ), central foveal thickness (CFT), subfoveal choroidal thickness (SCT) in our meta-analysis.

We eventually included five studies with a total of 401 participants. Our meta-analysis showed that nonacute infectious COVID-19 or post-COVID-19 patients presented significantly lower foveal VD of deep capillary plexus (WMD = -4.22, 95% CI [-8.00, -0.43]) and thinner SCT (WMD = -10.33, 95% CI [-19.08, -1.57]) than healthy controls. The foveal VD and parafoveal VD of superficial capillary plexus, parafoveal VD of deep capillary plexus, CFT, area, and perimeter of FAZ showed no significant differences between the groups.

The patients of nonacute infectious COVID-19 or post-COVID-19 displayed alterations in the retinal microvasculature and choroidal vessels, including a significantly lower foveal VD in deep capillary plexus and thinner SCT. The impairment may be a medium to long-term process. Close ophthalmic surveillance is necessary for COVID-19 patients or post-COVID-19 patients.