The Retinal Effects of COVID-19

A recent study published in PNAS Nexus has revealed that SARS-CoV-2, the virus responsible for COVID-19, can infect the retinal pigment epithelium (RPE) and compromise its function, raising concerns about potential long-term vision effects. Conducted by researchers at UCLA, the study notes how the SARS-CoV-2 Spike protein can enter and replicate within RPE cells, inducing inflammation and mimicking characteristics of age-related macular degeneration (AMD).

Using transgenic mouse models and human cell cultures, the researchers found that SARS-CoV-2 infects RPE cells via ACE2 and TMPRSS2 receptors, causing significant alterations in cell structure and function. The infection resulted in the activation of complement pathways and the release of inflammatory cytokines, similar to those observed in AMD. These changes disrupted the RPE's ability to maintain retinal health, including its essential role in photoreceptor maintenance.

Notably, the virus also compromised the RPE’s phagocytic capacity, a disruption which could accelerate retinal damage and degeneration. Variants of SARS-CoV-2, including Delta and Omicron, exhibited different infection dynamics, with Omicron showing a delayed but prolonged inflammatory response when compared with the original strain.

The findings suggest that SARS-CoV-2 infection of the RPE could have significant long-term consequences for vision, particularly for individuals experiencing post-acute sequelae of COVID-19, also known as “long COVID.” These effects could potentially increase the risk of developing retinal degenerative conditions, such as AMD.