Ozempic and Wegovy May Cause Optic Nerve Blindness

Key Points

• People taking semaglutide are more likely to develop a rare eye disease, according to a 2024 study.
• Non-arteritic anterior ischemic optic neuropathy is the leading cause of optic nerve blindness after glaucoma in the United States.
• Scientists could not prove without a doubt that semaglutide causes optic nerve problems, so more research is needed.

Semaglutide—the active ingredient in the brand-name drugs, Ozempic and Wegovy—is famous for helping people with obesity achieve their weight loss goals.

However, semaglutide, which is also used to manage type 2 diabetes, carries some potential risks. In addition to temporary vision changes, people taking semaglutide may be more likely to develop a rare eye disease that causes sudden blindness, indicated a 2024 study.

Can Ozempic or Wegovy affect your eyesight?

Temporary visual changes—mainly blurry vision—are a known side effect of semaglutide that usually lasts three to four months.

Some previous research has also suggested people taking semaglutide are more likely to develop new or worsening diabetic retinopathy or macular problems, according to the American Academy of Ophthalmology (AAO).

The latest study indicates a link between semaglutide and non-arteritic anterior ischemic optic neuropathy (NAION).

Researchers at Massachusetts General Brigham analyzed data from six years of medical records and 16,827 patients in the 2024 study published in JAMA Ophthalmology.

Of the study participants, who were mostly female, 710 had diabetes and 979 were overweight or obese. People in the diabetes cohort were 59 years old on average, while those in the remaining group were 47.

Doctors had prescribed semaglutide to 194 patients with type 2 diabetes and 361 patients who were overweight or obese. Another 516 people with diabetes received prescriptions for other antidiabetic medications, whereas 618 people in the overweight group received different types of weight loss medications.

The researchers found people with diabetes who took semaglutide were more than four times as likely to develop NAION as people with diabetes who didn't take the medication.

Specifically, 17 people taking semaglutide developed it, compared to six people taking other medications.

People taking semaglutide to lose weight were seven times more likely to develop NAION than those taking other weight loss drugs. Among this group, 20 people taking semaglutide and three taking other drugs were diagnosed with NAION.

Patients were most likely to develop NAION within the first year of taking the medication.

Non-arteritic anterior ischemic optic neuropathy affects roughly 2.3 to 10.3 people in every 100,000 people in the United States each year. It is the second leading cause of optic nerve blindness after glaucoma, according to the AAO.

This painless condition usually affects one eye because of a lack of blood flow to the optic nerve, which connects the eye to the brain, according to Brigham and Women's Hospital.

"Our findings should be viewed as being significant but tentative, as future studies are needed to examine these questions in a much larger and more diverse population," explained lead researcher Joseph F. Rizzo, M.D., director of neuro-ophthalmology at Boston's Massachusetts Eye and Ear in a news release.

"This is information we did not have before and it should be included in discussions between patients and their doctors, especially if patients have other known optic nerve problems like glaucoma or if there is pre-existing significant visual loss from other causes," Rizzo said.

How does semaglutide cause blindness?

This retrospective, observational study demonstrates a correlation between NAION and semaglutide use but does not prove cause and effect.

"It is premature to conclude that the association is causal. More research is necessary to test the hypothesis. Until then, patients should be aware of this information and, in consultation with their care team, make a careful, informed choice based on their individual risk profile," said neuro-ophthalmologist Andrew Lee, M.D., chair of the Blanton Eye Institute, department of ophthalmology at Houston Methodist Hospital in Houston, Texas and is professor of ophthalmology, neurology and neurosurgery at Weill Cornell Medicine.

The cause of NAION is unknown, but people with diabetes, high blood pressure and sleep apnea are more likely to develop it, according to Brigham and Women's Hospital. Smoking is another risk factor.

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Scientists don't fully understand the relationship between glucose-lowering medications like semaglutide and how they might affect eyesight, but changes in blood sugar levels can change the shape of the eye lens, according to the American Academy of Ophthalmology.

Semaglutide supports weight loss and helps manage type 2 diabetes by increasing levels of GLP-1, a hormone that stimulates insulin production, reduces hunger and increases satiety.

By prompting the body to create more insulin, semaglutide helps reduce blood sugar levels, which may cause temporary vision changes, such as blurriness.

Novo Nordisk, the manufacturer of Ozempic, is also investigating the potential link between semaglutide and diabetic retinopathy in a clinical trial.

Abnormally high blood sugar levels may cause blood vessels in the eye to leak, leading to diabetic retinopathy and vision loss, according to the AAO. A 1987 study published in January 1987 suggested that, in some cases, semaglutide may make diabetic retinopathy worse.

"For the majority of people, this won't be a problem and symptoms are manageable," said Raj Maturi, MD, F.A.S.R.S., founder of Retina Partners Midwest, operating three medical ophthalmology clinics in Indiana.

"Make sure to let your ophthalmologist know of any medications you are using and get your eyes checked regularly. They will track any vision changes and recommend potential treatments," Maturi said.

Can people become blind after taking semaglutide medications?

Researchers at Massachusetts General Brigham conducted their study after noticing an unusually high number of patients—about 100 a year—were developing NAIOA and that most of these people had been prescribed semaglutide.

Still, the condition is rare even among people taking semaglutide. Most experts agree the medication's benefits generally outweigh the potential risks.

"The use of these drugs has exploded throughout industrialized countries, and they have provided very significant benefits in many ways, but future discussions between a patient and their physician should include NAION as a potential risk," Rizzo said.

"It is important to appreciate, however, that the increased risk relates to a disorder that is relatively uncommon."

Visual changes are one of many potential side effects of semaglutide. Ozempic can cause erectile dysfunction, while other research has linked the medication to kidney damage, among other issues.

However, severe side effects are rare, and another recent study concluded that Ozempic doesn't increase suicidal thoughts risk as once thought. More common complaints, such as diarrhea and nausea, usually subside within a few weeks.

The bottom line

Taking semaglutide may raise your risk of several potential side effects, including visual changes. However, serious complications, such as optic nerve blindness, are rare.

Talk to your doctor if you're considering semaglutide as part of a medical solution to determine any risks.