Currently, there is no established link connecting mRNA COVID-19 vaccines to blindness or other eye problems. However, there are a number of case reports of blindness and other ocular side effects (eye problems) that are being researched to better understand if there is a causal link or not. There have not been enough cases documented in reporting systems or studies to determine whether these side effects are due to the vaccines or due to coincidence. 

What we know so far about the potential connection between mRNA COVID-19 vaccines and side effects of the eyes comes mostly from country-level reporting systems and case reports. 

One systematic review of multiple studies, case reports, and letters found that "ocular manifestations" (an eye condition that directly or indirectly results from a disease process in another part of the body) after receiving COVID-19 vaccines may appear on the eyelid, cornea and ocular surface, retina, uvea, nerve, and vessel. The ocular manifestations occurred up to forty-two days after vaccination, and vaccine-induced immunologic responses could be responsible.

The UK's Medicines and Healthcare products Regulatory Agency (MHRA) reporting system known as the Yellow Card Scheme has had 132 self-reported cases of blindness and 6,682 overall eye disorders reported since vaccine rollouts began across about 51 million people. 

To be sure, country level reporting systems–such as the Vaccine Adverse Event Reporting System (VAERS) in the U.S. and the U.K.’s MHRA Yellow Card Scheme–are good ways of identifying a potential side effect if high numbers of an event are routinely reported, but are not good ways of establishing a definitive link. The same is true of case reports in science. 

The best way to understand a connection between a vaccine and an outcome is through a large scientific trial, and the only true way to definitively know if a vaccine causes an outcome is through a large, controlled, randomized trial (where there is a vaccine group and control group). In the original Phase 3 trials of both the Pfizer-BioNTech vaccine and the Moderna vaccines–which were large controlled, randomized studies–eye problems were not reported as a side effect. 

However, this does not mean it’s not possible that mRNA vaccines might cause eye problems in very rare cases for a number of reasons. It’s possible that certain demographics were not represented in their studies, for instance, or that the sample sizes were not large enough to catch this side effect. This is why research is ongoing to understand the connection. In the meantime, physicians should be aware of the possible associations between COVID-19 vaccines and eye symptoms for the early diagnosis and treatment of potential vision problems or other complications.

Regardless of whether the connection is causal or not, current data suggests that the incidence rate of ocular symptoms is considerably lower in vaccinated subjects than in COVID-19 patients, particularly among children. One study showed nearly one in four children treated for COVID-19 at a Chinese hospital in early 2020 had mild eye problems, including eye discharge, conjunctivitis (pink eye), eye rubbing, eye pain, and eyelid swelling. Corneal nerve damage has been associated with “long COVID” and stroke as a result of COVID-19.

There have been claims recently that the MHRA’s Yellow Card Scheme report indicates that mRNA vaccines cause blindness and other eye disorders. This link is possible but not yet established and still being explored. 

It’s worth noting that there are multiple common vaccines that are known to be associated with side effects of the eyes: - Seasonal flu vaccine: In rare cases, some patients who received the flu vaccine experienced mild eye symptoms like eye redness, eye pain and blurred vision. - Measles-mumps-rubella (MMR) vaccine: Some research has shown that optic neuritis–which is inflammation affecting the optic nerve that sends signals from the back of the eye to the brain–is a rare complication from the MMR vaccine. - Chickenpox and shingles vaccines: It’s possible that the chickenpox vaccine (for children) and the shingles vaccine (for adults) may cause corneal inflammation in rare instances. 

As clear by the above three vaccines, we have both recommended and mandated vaccines on the market that have ocular side effects, with benefits that outweigh risks. For now, the benefits of the mRNA COVID-19 vaccines continue to outweigh side effects, including potential eye problems, which are still being explored as an outcome that’s causally linked to the vaccines. This link is also being explored in individuals who received non-mRNA vaccines, particularly inactivated vaccines such as the Sinopharm vaccine which a recent study found may be linked to adverse eye side effects.