Ozempic and NAION: Vision Loss Symptoms, Causes and Risk Factors

NAION stands for non-arteritic anterior ischemic optic neuropathy. It happens when not enough blood reaches the optic nerve, which connects your eyes to your brain. This typically leads to acute vision loss in one eye and mostly affects adults over 50, often upon waking. Research has linked Ozempic and other GLP-1 drugs containing the active ingredient semaglutide to an increased risk of NAION.

Doctors sometimes call NAION an “eye stroke” because, similar to a stroke, it is caused by a problem with blood flow. In NAION, the optic nerve is affected, not the brain. 

NAION can cause lasting vision problems, such as blurry spots, dark areas or reduced color and contrast. Some people keep good central vision but lose part of their peripheral vision. Others may have more serious vision loss.

There is no proven treatment to undo the damage from NAION. Most people’s vision remains the same after the onset of NAION, but some people’s vision improves or worsens.

The most common symptom of NAION is a sudden and painless loss of vision in one eye, which people often notice when they wake up in the morning, following a nap or while carrying out normal activities. Vision may become blurred or dimmed, and the affected eye may have a dark or grey area or a missing part of the visual field.

Vision changes are often most apparent in the lower part of the visual field, though other types of disturbances can also occur. In some cases, people experience reduced contrast or weakened color vision, a condition known as dyschromatopsia.

NAION usually starts in one eye, and studies indicate that about 15% to 25% of people who develop NAION in one eye will also develop it in the other.

When to Seek Emergency Care

If you experience a sudden change in vision, seek immediate medical attention. See an ophthalmologist or go to the emergency room, especially if the vision loss is sudden, occurs in one eye or is accompanied by other new symptoms.

Although no proven treatment for NAION can restore lost vision, early evaluation can help identify the cause. Rule out other serious conditions and address risk factors that might affect your remaining vision.

The European Medicines Agency’s safety committee (PRAC) has concluded that NAION is a very rare side effect of semaglutide. According to the regulatory agency, findings from several large epidemiological studies suggest that adults with Type 2 diabetes who take semaglutide may have twice the risk of developing NAION compared with those who do not take the medication.

The American Optometric Association’s Comprehensive Adult Eye and Vision Examination considers people taking GLP-1 RAs “at risk” patients.

Many of the health problems linked to NAION are also reasons why people might take Ozempic or other GLP-1 medicines. These include Type 2 diabetes, high blood pressure, high cholesterol, sleep apnea and obesity.

Ellen Relkin, an attorney representing people with NAION in lawsuits against Novo Nordisk, pointed to an eye exam that can spot one risk factor.

“There is a condition called ‘disc at risk,’ which is a crowded optic disc,” Relkin told Drugwatch. “Go to an optometrist, get an eye exam to see if you have this crowded disc at risk. And if you do, you should know that and discuss it with your doctor. Make an informed decision.”

The rise of Ozempic and other GLP-1 drugs has focused scientific scrutiny on these popular diabetes and weight loss drugs.

Overall, studies show that people taking semaglutide might have a higher risk of NAION, but the amount of risk changes from study to study. These differences may reflect the study population, comorbidities and study design.

Hathaway et al., JAMA Ophthalmology (2024)

A 2024 JAMA Ophthalmology study reviewed records from over 16,000 patients at an eye clinic in Massachusetts. Researchers compared people with Type 2 diabetes and people who were overweight or obese.

The study found that people with diabetes who took semaglutide had a much higher risk of NAION than those on other diabetes medicines. People who are overweight on semaglutide also had a higher risk than those using other weight-loss drugs. The scientists said more studies are needed to determine whether semaglutide causes NAION.

Danish Cohort Study (2024)

A Danish study followed over 424,000 people with diabetes from 2018 to 2024. Some took semaglutide every week, and some did not.

After several years, 218 people in the study developed NAION. People taking semaglutide had a significantly higher rate of NAION than those not taking it. After making adjustments for other factors, taking semaglutide was linked to about twice the risk of NAION.

Cai et al., JAMA Ophthalmology (2025)

A 2025 study in JAMA Ophthalmology examined health records from more than 37 million adults with diabetes across multiple countries. Researchers found a small increase in NAION cases among people using semaglutide — with a risk about 1.3 to 1.5 times higher — depending on how NAION was defined.

Researchers noted this risk was smaller than in previous studies, but additional studies are needed to establish causality.

As of October 2026, the FDA has not listed NAION as a warning for Ozempic. Novo Nordisk has updated its European labels to state that semaglutide may cause NAION in up to 1 in 10,000 people.

The label warns about another eye problem, diabetic retinopathy, and tells patients to talk to their doctor if they notice changes in their vision.

The FDA collects reports from doctors and patients about vision problems and other side effects from Ozempic and Wegovy. These reports can help identify safety issues, but they do not prove that the medicine caused the problem or show how often it occurs.

Ozempic has not been recalled. The FDA still approves it, and doctors can prescribe it. Right now, the FDA is investigating whether a special warning about NAION should be added to the label.

Some people who developed NAION after taking Ozempic or Wegovy have filed lawsuits. They say the drug companies did not do enough to warn about the risk of sudden vision loss. These lawsuits are in the early stages, and no trials have occurred yet.

Federal Ozempic lawsuits have been combined into a single litigation in Pennsylvania. This process is called multidistrict litigation, or MDL, and it lets one court handle many similar lawsuits together, making the process more efficient. You do not have to live in Pennsylvania to file a vision loss lawsuit.

The GLP-1 vision loss lawsuits are in MDL 3163. This is different from MDL 3094, which deals with claims about Ozempic side effects resulting in gastrointestinal injuries, such as gastroparesis, that are linked to GLP-1 medications.

Meanwhile at the state level, hundreds of Ozempic vision loss lawsuits have been grouped into a multicounty litigation in New Jersey.