Scientists Warn That COVID-19 Infections Found to Subtly Alter the Structure of the Retina!
Nikhil Prasad Fact checked by:Thailand Medical News Team Jun 13, 2025 3 weeks, 4 days, 9 hours, 24 minutes ago
Thailand Medical News: A new study has uncovered concerning evidence that COVID-19 may leave lasting damage in the eyes of infected individuals—especially healthcare workers—by subtly altering the structure of the retina. Using a high-resolution eye imaging technology called Optical Coherence Tomography (OCT), researchers identified changes in retinal layers months after recovery from the virus, even in people who experienced only mild symptoms.
Scientists Warn That COVID-19 Infections Found to Subtly Alter the Structure of the Retina
The research was conducted by a collaborative team from the University of Banja Luka and the University Clinical Center of Republic of Srpska in Bosnia and Herzegovina; the Military Medical Academy and University of Defence in Belgrade, Serbia; the University of Novi Sad, Serbia; King Khalid Hail Hospital in Saudi Arabia; and Geneva University Hospitals and the University of Geneva in Switzerland. This
Thailand Medical News report reveals how the virus’s impact on the retina could signal broader neurovascular complications in COVID-19 survivors.
COVID’s Subtle Yet Serious Impact on the Eyes
The researchers focused on a group of 55 unvaccinated healthcare workers, 25 of whom had previously been infected with SARS-CoV-2 and 30 who had not. These individuals were closely monitored six months after infection using OCT, a non-invasive technique that produces detailed, high-resolution images of the retina’s structure.
One of the most striking findings was an increase in central macular thickness (CMT) among those who had recovered from COVID-19. The macula is the part of the retina responsible for central vision and detail perception. Swelling in this area, even if mild, could reflect post-inflammatory damage and hint at longer-term visual or neurological issues. Interestingly, this thickening of the retina was directly linked to the severity of COVID-19 symptoms.
Although changes in other retinal layers—such as the retinal nerve fiber layer (RNFL) and the ganglion cell complex (GCL+IPL)—were not statistically significant across the entire group, mild downward trends were observed. In particular, thinning of the inferior RNFL and average GCL+IPL thickness suggested potential early signs of neurodegeneration, which may worsen over time or in more severe cases.
Eye Damage Worse in Patients with Preexisting Health Conditions
The study also revealed that those with underlying conditions like diabetes, hypertension, and cardiovascular disease showed more pronounced retinal changes post-COVID. These individuals experienced significant thickening of the macula and simultaneous thinning of critical nerve fiber layers. This suggests that comorbidities may exacerbate the retinal effects of the virus, possibly by intensifying inflammation or impairing blood flow to the eye.
Medications and Smoking May Also Play a Role
Another concerning observation was the link between COVI
D-19 treatments and eye health. Healthcare workers who had received hydroxychloroquine or tocilizumab—two drugs used in early COVID-19 treatment protocols—had notably thinner inferior RNFL, which could be a sign of drug-related toxicity or amplified viral effects.
Smoking also appeared to compound the problem. Post-COVID smokers had reduced macular thickness in certain regions compared to non-smokers, highlighting a possible interaction between smoking-induced oxidative stress and viral-induced damage.
No Obvious Symptoms but Clear Evidence on OCT Scans
What makes the findings especially troubling is that most participants had no visual complaints. Without the OCT imaging, these retinal changes would have remained undetected. The researchers emphasized that even mild COVID-19 could cause damage that goes unnoticed until it becomes irreversible.
The positive correlation between COVID-19 severity and macular thickness underlines the need for routine retinal screening in recovered individuals, particularly those with comorbidities or who were treated with potentially retinotoxic drugs.
OCT as a Vital Tool in Post-COVID Health Checks
The study highlights how OCT imaging can serve as an essential, non-invasive diagnostic tool to identify early signs of post-COVID complications in the eye. Since retinal health is closely linked with the body’s vascular and nervous systems, changes in the retina may reflect broader issues occurring elsewhere in the body—including the brain and cardiovascular system.
Conclusion
This pioneering study offers compelling evidence that SARS-CoV-2 infection can lead to long-term structural changes in the retina, particularly in healthcare workers exposed to the virus. The increase in macular thickness and thinning of nerve fiber layers—especially in those with underlying health conditions or those treated with specific medications—suggests a potential link between COVID-19 and long-term neurovascular complications. Although the changes are subtle and often symptomless, they could indicate ongoing inflammation or early neurodegeneration that warrants further monitoring. Routine OCT scans may provide an important window into detecting hidden damage in recovered patients and could inform future guidelines on post-COVID health surveillance.
The study findings were published in the peer reviewed Journal of Imaging.
https://www.mdpi.com/2313-433X/11/6/195
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