Ozempic and Mounjaro Drug Class Linked to 35% Higher NAION Vision Loss Risk

Researchers are calling on doctors to monitor patients taking GLP-1s, to watch for early signs of non-arteritic anterior ischemic optic neuropathy (NAION).

A new study provides more evidence that side effects of diabetes and weight loss drugs like Ozempic and Wegovy may cause a rare eye condition, which results in sudden and possibly permanent vision loss.

Researchers from Veterans’ Affairs published data in JAMA Network Open late last month, which appears to confirm previous findings linking GLP-1 medications with an increased risk of non-arteritic anterior ischemic optic neuropathy (NAION). The condition damages the optic nerve, potentially resulting in problems ranging from blurred vision to blindness.

GLP-1 NAION Risks

GLP-1 receptor agonists have become widely popular in recent years. Originally introduced as treatments for Type 2 diabetes, including Ozempic and Mounjaro, the drugs saw a rapid rise in use after they were linked to weight loss and a lower risk of certain metabolic conditions. That demand led to weight-loss formulations such as Wegovy and Zepbound. Other medications in the same class include Trulicity, Rybelsus, Saxenda and Victoza.

However, concerns about the vision loss risks emerged in June 2024, when Harvard researchers published a study linking GLP-1 use to NAION. Those findings warned that the research team had detected a seven-fold increased risk of the debilitating vision condition, particularly among users of Ozempic and Wegovy, both of which are based on the active ingredient semaglutide.

Since the revelation, more studies have backed those findings and manufacturers Novo Nordisk and Eli Lilly now face dozens of GLP-1 vision loss lawsuits, alleging that the companies knew, or should have known, about the potential NAION risks. The lawsuits say the manufacturers placed their desire for profits over patient safety by failing to warn patients or the medical community.

GLP-1 NAION Study

In the new study, researchers with the VA St. Louis Health Care System in Missouri looked at nationwide electronic VA health records. Led by Taeyoung Choi, MS, the team compared the three-year risk of NAION between GLP-1 users and those who took sodium-glucose cotransporter-2 (SGLT2) inhibitors. SGLT2 drugs are an older class of diabetes medications that includes Jardiance, Invokana and Farxiga.

Out of 588,168 participants, 139,546 started GLP-1 treatment, while 448,622 took a form of SGLT2 inhibitors. According to the findings, three years of follow-up revealed that NAION affected 39 per 10,000 persons taking drugs like Ozempic and Mounjaro, compared to just 29 per 10,000 persons taking Jardiance or Invokana and similar drugs, resulting in what researchers determined was a 35% increased risk among GLP-1 users.

The researchers noted that they found that ratio persisted regardless of the type of NAION diagnosis used, and that GLP-1 medications were not linked to an increased risk of any other vision disorders that they could detect.

They concluded that GLP-1 use was linked to a “modestly increased risk of NAION,” though they noted that the absolute risk remained low. The researchers called for heightened vigilance among health care providers for early signs of NAION among GLP-1 users.

GLP-1 NAION Lawsuits

Over the past year, several dozen GLP-1 NAION lawsuits have been filed in federal courts nationwide and consolidated before U.S. District Judge Karen Marston in the Eastern District of Pennsylvania for coordinated discovery and pretrial proceedings as part of a multidistrict litigation (MDL).

To help manage the litigation, the judge is expected to schedule a series of bellwether trials that will help the parties determine how juries could respond to evidence and testimony likely to be repeated throughout the litigation. However, before such trials can be held, Judge Marston will be asked to rule on a number of pretrial motions, which will involve complex pharmaceutical and medical issues.

Judge Marston has scheduled a “Science Day” for June 2, 2026, to help bring the court up to speed on research, like this latest study, linking NAION to Ozempic and Wegovy in a non-adversarial setting.

GLP-1 Stomach Paralysis Lawsuits

The same judge is overseeing a similar, but separate MDL involving more than 3,000 GLP-1 stomach paralysis lawsuits, which began to be filed after the drugs were linked to increased risks of gastroparesis and bowel obstruction.

Judge Marston indicates she also plans to hold a series of bellwether trials for this litigation. 

After the bellwether trials and pretrial proceedings are concluded, if the parties have not reached a GLP-1 settlement agreement or other resolution, Judge Marston is likely to begin remanding cases back to their originating districts for individual trial dates.

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