According to the study:
"Retinal vein occlusion (RVO) is the second most prevalent cause of visual loss related to retinal vascular diseases, after diabetic retinopathy. RVO is related to thromboembolism caused by vessel compression, vasospasm, or degeneration of vascular walls."
The study included 7,318,437 people from the TriNetX network divided into vaccinated and unvaccinated individuals, and they concluded that "individuals with COVID-19 vaccination had a higher risk of all forms of retinal vascular occlusion in 2 years after vaccination, with an overall hazard ratio of 2.19 (95% confidence interval 2.00–2.39)."
This is one of the first large scale studies published that examined COVID-19 vaccination side effects which are continuing more than 2 years following a COVID-19 injection.