Semaglutide-based medications, particularly the higher-dose weight-loss drug Wegovy, have been associated with an increased risk of a rare but serious eye condition known as non-arteritic anterior ischemic optic neuropathy (NAION). Often referred to as an “eye stroke,” NAION can lead to sudden, painless vision loss, typically in one eye, and may result in permanent partial or complete blindness.
Understanding NAION
NAION occurs when blood flow to the optic nerve is temporarily reduced or blocked, causing damage to the nerve fibers. Unlike a traditional stroke, it is not caused by a blood clot but by insufficient circulation. The condition is uncommon in the general population, with an estimated incidence of 2 to 10 cases per 100,000 people per year. Risk factors include obesity, diabetes, high blood pressure, and sleep apnea—conditions frequently present in individuals prescribed semaglutide drugs like Wegovy, Ozempic, and Rybelsus.
There is currently no effective treatment to reverse the vision loss once NAION develops.
Key Research Findings
A 2024 study published in JAMA Ophthalmology analyzed data from over 16,000 patients and found that individuals using semaglutide for Type 2 diabetes had approximately four times the risk of NAION compared to those on other diabetes medications. The risk was even higher—about seven times—for those using it primarily for weight management.
More recent 2026 analyses of FDA adverse event reports, published in the British Journal of Ophthalmology, highlighted a stronger signal with Wegovy. The higher-dose formulation showed nearly five times the reporting odds of ischemic optic neuropathy compared to Ozempic. Additionally, the risk appeared approximately three times higher in men than in women.
Regulatory Responses
In June 2025, the European Medicines Agency (EMA) classified NAION as a “very rare” side effect of semaglutide medications, potentially affecting up to 1 in 10,000 users. The agency recommended updating product labels and advised stopping treatment if NAION symptoms occur. Similar warnings have been issued in the UK.
As of May 2026, the U.S. FDA continues to monitor the situation but has not yet mandated a specific label warning for NAION on Wegovy or related drugs.
Balancing Risks and Benefits
While the relative risk increase is notable, the absolute risk remains low given NAION’s rarity. Semaglutide drugs have demonstrated significant benefits, including substantial weight loss, improved blood sugar control in diabetes, and reduced cardiovascular risks for many patients.
Other eye-related effects associated with these medications include temporary blurry vision due to blood sugar fluctuations and potential worsening of diabetic retinopathy in patients with pre-existing eye disease, particularly during rapid glycemic improvements.
Higher-risk groups may include men, users of higher doses such as Wegovy, and individuals with multiple vascular risk factors.
Recommendations
This information is for educational purposes and does not constitute medical advice. Patients taking or considering Wegovy, Ozempic, or similar medications should consult their healthcare provider. Any sudden changes in vision should be evaluated immediately by an eye specialist. Regular eye examinations are advisable, especially for those with diabetes or other risk factors.
Ongoing research and post-marketing surveillance will continue to refine our understanding of this potential association. Individuals experiencing symptoms or concerned about risks are encouraged to discuss them openly with their doctor.
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