A study published in the British Journal of Ophthalmology found that Wegovy users may face nearly five times the risk of developing ischemic optic neuropathy (ION), including non-arteritic anterior ischemic optic neuropathy, or NAION, compared to patients taking Ozempic.

If you or a loved one experienced sudden vision loss or were diagnosed with NAION after taking Wegovy, Ozempic, or another GLP-1 medication, you may qualify to file a lawsuit and receive compensation.  

Find out whether you qualify or start your claim today by contacting the lawyers at Hissey Mulderig & Friend today. You can speak with an attorney by calling our office toll-free at 1-866-806-8117 or by filling out our free claim submission form on the right side of this page. 

What the British Journal of Ophthalmology Study Found

The study, titled “Ischemic optic neuropathy with semaglutide: global observational analysis of sex- and formulation-specific risk,” was conducted by researchers at the University of Ottawa and the University of Toronto. The team, led by Moiz Lakhani and Dr. Edward Margolin, analyzed more than 30 million adverse event reports submitted to the FDA’s Adverse Event Reporting System (FAERS) between 2017 and 2024. 

Among approximately 31,774 reports involving semaglutide, the researchers found that semaglutide was the only GLP-1 drug in the study associated with a significant safety signal for ischemic optic neuropathy. But the risk was not evenly distributed across semaglutide products. 

Wegovy, the higher-dose injectable semaglutide approved for weight loss, showed the strongest association with ION. The adjusted odds of ION were nearly five times higher for Wegovy compared to Ozempic.  

Why Wegovy May Carry a Higher NAION Risk Than Ozempic

Ozempic and Wegovy both contain semaglutide, but they are prescribed at different doses. Ozempic is available in injectable doses up to 2 mg per week and is FDA-approved for type 2 diabetes. Wegovy is approved for weight loss at doses up to 2.4 mg per week. 

The study’s authors suggest that the difference in NAION risk between the two drugs may be related to dosage. Higher doses of semaglutide can lead to faster weight loss and more rapid metabolic changes, which may in turn cause shifts in blood volume, blood pressure drops during sleep, and changes in blood flow to the optic nerve.  

Dr. Margolin, one of the study’s co-authors, stated that NAION is likely a real side effect of semaglutide, and that more aggressive weight loss may increase the physiological stress that leads to sudden vision loss. 

This proposed dose-dependent relationship is significant because it suggests that the millions of Americans who take Wegovy specifically for weight loss, often at higher doses than those prescribed for diabetes, may be at greater risk for vision problems than previously understood.  

Earlier research, including a 2024 study published in JAMA Ophthalmology, had already found that semaglutide users were up to eight times more likely to be diagnosed with NAION. The new British Journal of Ophthalmology findings build on that research by identifying dose and formulation as key variables in determining risk. 

Men Face Three Times the Risk of Women

The study also revealed important differences between men and women. In analyses adjusted for age and sex, the risk of ION was approximately three times higher in men than in women.  

The highest reporting odds of all were found among men taking Wegovy, while Ozempic-related cases were more frequently reported among women. 

These findings could be relevant for patients and their doctors when weighing the risks and benefits of GLP-1 medications, particularly for male patients taking high-dose semaglutide for weight management. 

What Is NAION and Why Is It So Serious?

NAION, or non-arteritic anterior ischemic optic neuropathy, occurs when blood flow to the optic nerve is suddenly reduced or cut off, causing rapid vision loss. The condition is sometimes called an “eye stroke.” Vision loss from NAION typically strikes one eye, is painless, and often occurs upon waking. In many cases, the damage is permanent. There is currently no proven treatment to restore vision lost to NAION. 

The condition is the second most common cause of optic nerve-related vision loss in adults over 50. People with diabetes, high blood pressure, sleep apnea, and other cardiovascular risk factors (the very populations most likely to be prescribed GLP-1 medications) are already at elevated baseline risk for NAION.  

Symptoms of this condition may include: 

• Sudden blindness in one eye 
• Blurry vision 
• Dimming of vision, and  
• Weakened color perception.  

About 15 percent of NAION patients eventually experience vision loss in their other eye as well. Because NAION cannot currently be reversed, early recognition of symptoms and prompt medical evaluation are critical.  

For answers to common questions about NAION and its connection to GLP-1 drugs, see our NAION FAQ. 

What This Means for the GLP-1 NAION Litigation

The British Journal of Ophthalmology study is the latest in a growing body of research linking GLP-1 drugs to NAION, and it arrives at a critical moment in the legal landscape.  

In December 2025, the U.S. Judicial Panel on Multidistrict Litigation created MDL No. 3163, a dedicated federal proceeding to consolidate lawsuits brought by patients who developed NAION after taking GLP-1 drugs including Ozempic, Wegovy, Mounjaro, and others.  

As of April 2026, 73 cases are pending in that MDL, with more expected as awareness of the link between semaglutide and vision loss continues to grow. A Science Day hearing, in which both sides will present scientific evidence about GLP-1 drugs and NAION to the presiding judge, is scheduled for June 2, 2026. 

Meanwhile, European regulators have already acted. In June 2025, the European Medicines Agency classified NAION as a “very rare” side effect of semaglutide and recommended label updates for Ozempic, Wegovy, and Rybelsus.  

The UK’s Medicines and Healthcare products Regulatory Agency (MHRA) published a similar safety update in February 2026, advising that patients who experience any sudden change in vision while taking semaglutide should be urgently referred for an eye examination.  

As of this writing, the U.S. FDA has not yet added a specific NAION warning to semaglutide drug labels, although its Sentinel System is actively monitoring the issue.  

The lawsuits in MDL 3163 allege that manufacturers Novo Nordisk and Eli Lilly failed to adequately warn patients and prescribers about the NAION risk associated with their GLP-1 drugs. 

Contact Hissey Mulderig & Friend About Your GLP-1 Vision Loss Claim

If you or someone you love experienced sudden vision loss, blindness, or a diagnosis of NAION while using a GLP-1 drug, you may be entitled to compensation. 

Our law firm, Hissey Mulderig & Friend, currently represents clients across the United States who developed NAION or other serious eye problems after taking Ozempic, Wegovy, or other GLP-1 medications. 

Our attorneys work on a strict contingency basis. This means you will never have to pay legal fees or other costs associated with filing a lawsuit unless we are able to successfully recover damages in your case. 

To learn more about your legal rights, talk with a lawyer, or to start the process of filing your claim today, contact Hissey Mulderig & Friend by calling our office toll-free at 1-866-806-8117. You can also submit your information online by filling out our free Ozempic and Wegovy claims evaluation form, located at the top of this page.