Researchers at the University of Missouri School of Medicine have identified a concerning effect of the virus that causes COVID-19: it can compromise the protective barrier of the retina and trigger a sustained inflammatory response within the eye. The presence of SARS-CoV-2 spike antigen in the body for extended periods may drive microaneurysms in the inner retina and lead to other serious ocular outcomes. These findings were published in PLOS Pathogens and add to the growing body of evidence about how the virus can affect eye health beyond the respiratory system.
In controlled experiments, scientists infected a cohort of laboratory mice with SARS-CoV-2. The results showed that the virus could reach the inner surface of the eye without direct exposure to ocular tissues. The researchers explained that once the virus enters the bloodstream, it can cross the blood-retinal barrier, a tight network of epithelial cells that normally blocks large molecules from entering retinal tissue via blood vessels. This breach enables viral components to reach retinal cells and potentially disrupt normal function.
Further observations revealed that prolonged retention of the SARS-CoV-2 spike antigen in the retina correlated with an inflammatory process and damage to the cells forming the blood-retinal barrier. This raises the risk of adverse retinal conditions such as microaneurysms, arterial occlusions, and bleeding within ocular vessels. The longer the viral antigens remain present in the eye, the greater the chance of experiencing meaningful declines in vision over time. The work underscores that even in individuals with otherwise healthy immune systems, the retina can be a site of viral-induced inflammation and injury, with higher likelihood in those with elevated blood pressure or diabetes where vascular health is already compromised.
These findings align with a broader understanding that immune status, vascular health, and metabolic conditions can influence how the virus impacts the eye. The Missouri study emphasizes the need for ongoing surveillance of ocular health in patients recovering from COVID-19 and for clinicians to consider retinal monitoring in at-risk groups. While the research is preliminary and conducted in animal models, it provides a crucial biological basis for why the retina could be vulnerable and why preserving retinal barrier integrity is important for protecting vision in the context of viral infections.
Past work in this area has hinted at new paths for treating hereditary blindness, but the current results specifically highlight how infectious agents might interact with ocular tissues. They invite a broader conversation about protective strategies to safeguard retinal health in the face of systemic infections and reinforce the idea that eye health should be part of comprehensive infectious disease care.