Since the introduction of COVID-19 vaccines, there have been case reports of retinal vascular occlusion in temporal association with immunisation. This caused uncertainty among some people about the COVID-19 vaccine. Billions of doses of vaccine have now been administered worldwide. A large-scale study on this issue brings clarity.2
Several researchers have already racked their brains over this question. What mechanisms could underlie retinal vascular occlusion occurring acutely after COVID-19 vaccination? The following mechanism is conceivable: vaccine-induced immune thrombotic thrombocytopenia is a rare complication of COVID-19 vaccination with mRNA vaccines. Vaccine-induced immunothrombotic thrombocytopenia could result in systemic ischaemic and thrombotic events in various organ systems of the body and thus also affect the vascular system of the eye.2
Ian Dorney's research group recently published a scientific study on 13 April 2023 in which they investigated whether retinal vascular occlusions could be a possible complication of vaccinations. For this purpose, they examined patients in whom a new retinal vascular occlusion had occurred within 21 days after immunisation. In addition to the mRNA-COVID-19 vaccine, the following vaccines were included in the data analysis: Influenza, tetanus, diphtheria and pertussis vaccine (Tdap vaccine). They paid particular attention to the incidence of venous retinal vascular occlusion after vaccination.2
Their retrospective data analysis included the records of a total of 103 million patients. The research group used the electronic health record (EHR) research network TriNetX analytics platform for this purpose. This enabled a population-based cohort design to be created. The datasets were searched for the presence of specific vaccination codes (Common Procedural Technology). Cases of newly diagnosed retinal vascular occlusion within 21 days of vaccination were specifically searched for. Relative risks were determined via propensity score matching based on demographic characteristics (age, sex, race and ethnicity) and comorbidities such as hypertension, diabetes and hyperlipidaemia.2
In 0.003% of the 3,108,829 patients who received mRNA-COVID-19 vaccination, new retinal vascular occlusion occurred within the first 21 days after vaccination. The mean age of the patients was around 51 years. The female gender predominated with 56.4%. The research group compared this result with the occurrence of RVO after one of the other previously mentioned vaccinations. According to propensity score matching (PSM), the relative risk for the occurrence of a new RVO after the first dose of vaccination with the mRNA-COVID-19 vaccine was not significantly different from the relative risk after influenza or Tdap vaccination.
The research group concluded that RVO occurring acutely after mRNA-COVID-19 vaccination is an extremely rare diagnosis. There was no significant difference from influenza or Tdap vaccination in the incidence of RVO.2 Interestingly, the risk of RVO after mRNA-COVID-19 vaccination actually decreased after the second dose of vaccine. Thus, the relative risk for the occurrence of RVO was 2.25 times higher after the first vaccination dose than after the second vaccination dose. It should be noted that these results cannot be applied to all other COVID-19 vaccines.3