Retinal vascular occlusions during COVID-19: an epidemiological survey

To evaluate whether the COVID-19 pandemic was associated with changes in the incidence of retinal vascular occlusions.

We performed a retrospective cohort study at the Jules-Gonin Eye Hospital (Lausanne). All new diagnoses of central retinal vein occlusion (CRVO), branch retinal vein occlusion (BRVO), central retinal artery occlusion (CRAO), and branch retinal artery occlusion (BRAO) between January 1, 2019 and December 31, 2020 were included. Regional COVID-19 case counts were obtained from public health records. Incidence rate ratios (IRR) comparing 2019 cases versus 2020 were calculated using official population data. Pearson correlation was used to explore temporal associations between monthly COVID-19 cases and retinal vascular events. The study period largely reflects natural infection exposure, as COVID-19 vaccination in Switzerland began on December 23, 2020.

In 2019, 66 retinal vein occlusions (38 CRVO, 28 BRVO) and 20 arterial occlusions (9 CRAO, 11 BRAO) were recorded. In 2020, 49 retinal vein occlusions (34 CRVO, 15 BRVO) and 21 arterial occlusions (14 CRAO, 7 BRAO) were recorded. The IRR for 2020 versus 2019 was 0.73 for vein occlusions (95% CI 0.51-1.05; p=.093) and 1.04 for arterial occlusions (95% CI 0.57-1.90; p=.896). Monthly analysis showed no significant temporal association between COVID-19 incidence and retinal vascular events (p=.08).

In this regional study, we did not observe an increase in retinal vascular occlusive events during the early phase of the COVID-19 pandemic. While biologically plausible mechanisms have been proposed, these population-level trends do not support a strong association.