Nikhil Prasad Fact checked by:Thailand Medical News Team Sep 11, 2026 21 minutes ago
COVID-19 may have lasting consequences for the eyes of people with type 2 diabetes, with a massive multicenter study finding that patients with recorded SARS-CoV-2 infection had a substantially higher subsequent risk of diabetic retinopathy, including potentially vision-threatening forms of the disease.
COVID-19 was associated with increased subsequent diabetic retinopathy risk among adults with type 2 diabetes
Diabetic retinopathy develops when diabetes damages small blood vessels in the retina and is a major cause of preventable vision loss. Researchers investigated whether COVID-19 could be associated with this complication beyond the acute infection period.
More Than 1.5 Million Matched Patients
Researchers analyzed electronic health records from the TriNetX Global Collaborative Network, which included 177 participating healthcare organizations. After propensity-score matching, the analysis included 773,768 adults with type 2 diabetes who had COVID-19 and an equal number of matched controls.
The researchers were Kuo-Chuan Hung from the Department of Anesthesiology, Chi Mei Medical Center, Tainan, Taiwan; Ting-Sian Yu from the Department of Anesthesiology, E-Da Hospital, I-Shou University, Kaohsiung, Taiwan; and Su-Zhen Wu and I-Wen Chen from the Department of Anesthesiology, Chi Mei Hospital, Liouying, Tainan, Taiwan.
Striking Increase in Retinal Disease
This
Thailand Medical News report highlights that diabetic retinopathy was recorded in 2.17% of COVID-19 patients compared with 1.64% of controls. COVID-19 was associated with a 51% higher relative hazard of diabetic retinopathy.
More concerning was the pattern among specific forms of retinal disease. Non-proliferative diabetic retinopathy showed a 53% higher hazard, while proliferative diabetic retinopathy—an advanced form associated with serious vision complications—showed a 67% higher hazard. Diabetic macular edema had the strongest association, with a 75% higher hazard.
The findings remained consistent when researchers restricted analyses to survivors, patients receiving healthcare, and patients with documented eye-care visits. In the two-year landmark analysis, the hazard of overall diabetic retinopathy was 92% higher. Severe COVID-19 was separately associated with increased hazards of overall retinopathy, proliferative disease, and macular edema.
Why COVID-19 Could Matter
Researchers cautioned that the study cannot establish that COVID-19 directly causes retinal damage. Possible explanations include post-COVID endothelial dysfunction, inflammation, immunothrombosis, microvascular injury, and episodes of unstable blood glucose. These remain hypotheses rather than proven mechanisms.
Conclusions
The results suggest COVID-19 history could represent an additional retinal risk marker in people with type 2 diabetes, particularly because associations extended to vision-threatening disease. However, observational data, diagnostic coding, unmeasured confounding, and differences
in ophthalmic surveillance mean prospective studies using standardized retinal imaging are needed before screening recommendations should change.
The study findings were published in the peer reviewed journal: Frontiers in Endocrinology.
https://www.frontiersin.org/journals/endocrinology/articles/10.3389/fendo.2026.1914361/full
Read Also:
https://www.thailandmedical.news/articles/coronavirus
https://www.thailandmedical.news/articles/long-covid
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