COVID-19 pandemic linked to no significant change in retinal vascular occlusion incidence at a Swiss eye hospital.

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Frontiers in Medicine Published April 27, 2026 Medically reviewed April 27, 2026 DOI ↗ By Dr. Lars van Dijk, PhD · Surgical, Procedural & Diagnostic

Key Takeaway

Note that population-level trends do not support a strong association between COVID-19 and retinal vascular occlusion incidence.

This retrospective cohort study examined new diagnoses of retinal vascular occlusions at the Jules-Gonin Eye Hospital in Lausanne from January 1, 2019, to December 31, 2020. The study compared cases from 2019 (pre-pandemic) to 2020 (during the early COVID-19 pandemic) to assess incidence changes.

In 2019, there were 66 retinal vein occlusions and 20 arterial occlusions. In 2020, there were 49 retinal vein occlusions and 21 arterial occlusions. The incidence rate ratio for vein occlusions was 0.73 (95% CI 0.51–1.05; p=.093), indicating a non-significant decrease. For arterial occlusions, the IRR was 1.04 (95% CI 0.57–1.90; p=.896), showing no significant change.

A secondary analysis found no significant temporal association between monthly COVID-19 case counts and retinal vascular events (p=.08). Safety data were not reported, as this was an epidemiological survey of diagnostic trends.

Key limitations include the study period reflecting natural infection exposure, as COVID-19 vaccination in Switzerland began only on December 23, 2020. The findings are observational and do not establish causality.

Practice relevance is limited to population-level trends, which do not support a strong association between COVID-19 and retinal vascular occlusive events. Clinicians should interpret these results cautiously, given the non-significant p-values and retrospective design.

Study Details

Study typeCohort

EvidenceLevel 3

PublishedApr 2026

View Original Abstract ↓

PurposeTo evaluate whether the COVID-19 pandemic was associated with changes in the incidence of retinal vascular occlusions. MethodsWe 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.ResultsIn 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).ConclusionsIn 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.