Retinal Vascular Density and Thickness Changes May Follow COVID-19 Vaccination

Individuals undergoing COVID-19 vaccination with the Pfizer-BioNTech vaccine may experience retinal vascular density and thickness changes within a 3-day period, according to a study published in Microvascular Research. These changes may be attributed to vascular endothelial damage and inflammation, the report suggests.

Researchers included 40 health care professionals (60% women; mean age, 37.65 years) in the investigation and performed optical coherence tomography-angiography (OCT-A) assessment prior to COVID-19 vaccination and within 3 days following vaccination. The team compared retinal vascular density and thickness measurements obtained before and after COVID-19 vaccination.

Compared with baseline values, participants undergoing vaccination experienced a significant reduction in total vascular (52% vs 50%; P <.0001), foveal vascular (21% vs 19.8%; P =.009), parafoveal vascular (54.4% vs 5.7%; P <.0001) and perifoveal vascular density of the superficial (51.4% vs 50.5%; P =.001) and deep capillary plexus (55.5% vs 52.1%; P =.04). Retinal foveal thickness and total retinal parafoveal thickness values increased significantly compared with pre-vaccination values (254 vs 258 µm; P =.03 and 319 vs 321 µm; P =.05, respectively).

“The etiology of the ocular side effects of the Pfizer-BioNTech vaccine has not yet been clarified,” according to the researchers. “These side effects are considered to be caused by a component of the vaccine, a hypersensitivity reaction, or autoimmunity. It has also been suggested that spike protein, human adenovirus, or other viral antigens may be responsible for such side effects.”

Study limitations include a small convenience sample, short study duration, and the inclusion of only 1 vaccine type.