A new study from Mass Eye and Ear suggests that people taking semaglutide—a drug sold under the names Ozempic and Wegovy—might have a higher chance of getting a rare but serious eye disease that can cause permanent vision loss.
This condition is called NAION, which stands for non-arteritic anterior ischemic optic neuropathy. It happens when blood flow to the optic nerve is suddenly reduced. This nerve sends visual information from the eye to the brain. When it is damaged, it can cause blindness in one eye that usually doesn’t get better.
The study was led by Dr. Joseph Rizzo, an eye and brain specialist at Mass Eye and Ear and a professor at Harvard Medical School. His team found that people with diabetes who were taking semaglutide were more than four times as likely to get NAION compared to people taking other diabetes drugs.
For people using semaglutide for weight loss, the risk was even higher—more than seven times greater. The findings were published in JAMA Ophthalmology on July 3, 2024.
NAION is uncommon. It affects around 10 out of every 100,000 people. It is the second most common cause of optic nerve blindness after glaucoma. It has no cure. The vision loss usually happens without pain and develops over a few days. Once the damage is done, it rarely improves.
This study started in late 2023 when doctors noticed something unusual. In just one week, three people were diagnosed with NAION—and all three were taking semaglutide. This made the doctors curious, so they looked deeper into their records.
They reviewed medical records from more than 17,000 patients who had been treated at Mass Eye and Ear in the past six years. They compared patients with diabetes or obesity who took semaglutide to those who took other medicines for the same conditions.
Their results showed that NAION happened more often in people who used semaglutide. This raised concern that the drug may be linked to the condition.
Semaglutide was first made to help people with type 2 diabetes control their blood sugar. But doctors noticed it also helped people lose weight. So the drug became very popular for weight loss too. It was first sold as Ozempic in 2017 and later as Wegovy in 2021. Millions of people now use it for diabetes or to lose weight.
Although the study results are concerning, the researchers say this does not prove that semaglutide causes NAION. There are some limits to the study. For example, Mass Eye and Ear sees many people with rare eye problems, so their patients may not be like most people.
Also, most people in the study were white, so the results might not apply to all races or groups. Another issue is that NAION is rare, so even small changes can affect the results. The study also could not confirm whether all patients took their medications as prescribed.
Still, the researchers say this is an important finding. More studies are needed to learn more. Future research should include more people from different backgrounds and explore why the risk seems different between diabetes patients and weight-loss patients.
People who are using Ozempic or Wegovy should not panic, but they should be aware of this possible risk. Anyone who is taking these drugs—especially if they have eye problems like glaucoma—should talk to their doctor about it.
Semaglutide has many benefits for weight loss and managing diabetes. But this new study adds a new piece to think about when deciding on treatment. Doctors and patients should stay informed as more research becomes available.
If you care about weight loss, please read studies that hop extract could reduce belly fat in overweight people, and early time-restricted eating could help lose weight.
For more health information, please see recent studies about a simple path to weight loss, and results showing a non-invasive treatment for obesity and diabetes.
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