Study Finds No Link Between COVID-19 Vaccination and Retinal Vascular Occlusion

Study Finds No Link Between COVID-19 Vaccination and Retinal Vascular Occlusion

April 19, 2023

Researchers from Case Western Reserve University and the Cleveland Clinic in Cleveland, Ohio, conducted an investigation into the possible connection between new-onset retinal vascular occlusion (RVO) and the COVID-19 vaccine.

The study compared the association with two previously used vaccines and analyzed data from over 3 million patients. The results, which were published in JAMA Ophthalmology, indicate that there is no link between mRNA COVID-19 vaccination and newly diagnosed RVO.

The purpose of the study, titled "Risk of New Retinal Vascular Occlusion After mRNA COVID-19 Vaccination Within Aggregated Electronic Health Record Data," was to address recent literature documenting acute cases of RVO following mRNA COVID-19 vaccination. Given that RVO can cause vision loss or blindness, conducting an epidemiological investigation to assess this possible correlation is critical for public health. The same journal issue includes an Invited Commentary by Lee M. Jampol and Maureen G. Maguire.

It's crucial to emphasize that numerous studies, like this one, are necessary to distinguish the actual disease data from the chaos of a global medical event. There will inevitably be associations between COVID-19 mass vaccinations and various illnesses. However, the primary factor in these correlations is the shared experience of people getting vaccinated, which is happening almost everywhere all at once.

For example, the vaccine might be linked to individuals around 40 years old requiring glasses for the first time. While this age group experiences the need for glasses every year, only by comparing this to the shared medical event (vaccination) could the occurrences seem related, even though they are not.

This phenomenon was a significant reason for people's concern over childhood vaccinations, as autism symptoms often emerge around the same period that children receive vaccinations. Furthermore, an increase in awareness and early diagnosis of autism, coupled with active campaigns spreading misinformation about the trace amounts of mercury used as a stabilizer, led people to believe there was a link when there was none.

After the medical community removed mercury from vaccines, the diagnosis rates for autism still rose due to advancements in recognition and diagnosis. If we were to base conclusions on correlative thinking, one might falsely assume that the trace amounts of mercury stabilizer in the vaccines helped prevent certain autism cases. This is precisely why correlations alone do not constitute science, and correlations in studies are not indicative of causation. Therefore, a study that demonstrates a null result, a lack of a link between a vaccine and a specific disease, can be an invaluable public health service, even if the only curative discovery is providing accurate information.

Researchers conducted a study to determine how frequently patients were newly diagnosed with RVO shortly after receiving the mRNA COVID-19 vaccine. To accomplish this, they compared the present data with previous vaccines for influenza, tetanus, diphtheria, and pertussis (Tdap).

The study employed a retrospective population-based cohort design, utilizing the TriNetX Analytics platform, an electronic health record research network with the deidentified data of over 103 million patients. Researchers searched the data of patients within the 103 million for instances of vaccinations and newly diagnosed RVO within 21 days of vaccination.

Out of the 3,108,829 age-appropriate patients who received the mRNA COVID-19 vaccine, only 104 (0.003%) patients received a new diagnosis of RVO within 21 days of vaccination. When compared to the yearly statistical diagnosis rate for RVO (approximately 150 per 100,000 individuals), 0.003% is approximately one-third of what one would expect to find in a 21-day span (about 58 per 100,000 individuals per year).

The rate of new RVO diagnosis after the first dose of mRNA COVID-19 vaccination was not significantly different from that after influenza or Tdap vaccinations, but it was more than double the rate after the second dose of the mRNA COVID-19 vaccine. However, this does not indicate a correlation between the mRNA COVID-19 vaccine and reduced RVO diagnoses.

Cohort comparison

Comparisons of New International Statistical Classification of Diseases and Related Health Problems, Tenth Revision (ICD-10) Diagnoses of Retinal Vein Occlusion (RVO) Occurring Within 21 Days of Vaccinations After Propensity Score Matching. (mRNA indicates messenger RNA; Tdap, tetanus, diphtheria, pertussis.) a) For the first-dose mRNA COVID-19 cohort, n = 1 180 006. There were 45 patients (0.004%) with a new RVO diagnosis. For the second-dose mRNA COVID-19 cohort, n = 1 180 006. There were 93 patients (0.006%) with a new RVO diagnosis. b) For the first-dose mRNA COVID-19 cohort, n = 1 470 351. There were 69 patients (0.005%) with a new RVO diagnosis. For the influenza cohort, n = 1 470 351. There were 20 patients (0.002%) with a new RVO diagnosis. c) For the first-dose mRNA COVID-19 cohort, n = 718 400. There were 27 patients (0.004%) with a new RVO diagnosis. For the Tdap cohort, n = 718 400. There were 27 patients (0.004%) with a new RVO diagnosis. Credit: JAMA Ophthalmology (2023). DOI: 10.1001/jamaophthalmol.2023.0610

It is possible that the low numbers of RVO diagnoses could be due to the fact that RVO symptoms can begin subtly, and visiting the eye doctor during a pandemic might not have been a priority.

Additionally, the agreed-upon rate at which RVO occurs may be too high, and capturing data from millions of individuals around an arbitrary time point could be revealing this.

Alternatively, it could be that rare diseases with low occurrence rates do not fall neatly into arbitrary 21-day timeframes, which implies a risk in conducting a study like this. It is essential to note that had the statistical clustering been reversed with RVO diagnosis rates 3 or 6 times greater than expected, the study could have been interpreted as confirming an association that did not exist.

Based on the results, it can be concluded that the risk of newly diagnosed RVO after mRNA COVID-19 vaccination is extremely low, and there is no evidence indicating a link between the vaccine and RVO.

However, it is important to note that other diseases may still be subject to similar correlative studies, and it is essential to remember that correlation does not necessarily imply causation. In the event that such correlations are found, researchers, clinicians, science reporters, and the general public should remind themselves that correlation does not imply causation, repeating this statement three times in a calm, authoritative voice.


Ian Dorney et al, Risk of New Retinal Vascular Occlusion After mRNA COVID-19 Vaccination Within Aggregated Electronic Health Record Data, JAMA Ophthalmology (2023). DOI: 10.1001/jamaophthalmol.2023.0610

Lee M. Jampol et al, No Red Flags for Risk of Retinal Vascular Occlusion After mRNA COVID-19 Vaccination, JAMA Ophthalmology (2023). DOI: 10.1001/jamaophthalmol.2023.0925