About one in eight American adults now use a GLP-1 medication such as Ozempic, Wegovy, Mounjaro, or Zepbound for diabetes or weight management. Recent headlines and lawsuits have linked these drugs to sudden vision loss, and it has become one of the most common questions our patients ask us.
The short answer: researchers have found a possible link between semaglutide (and, in fewer studies, tirzepatide) and a rare eye condition called NAION. However, the overall risk is very small, and a direct cause has not been proven. Here is what the latest evidence shows and what we recommend for our patients.
What Is NAION?
Non-arteritic anterior ischemic optic neuropathy, or NAION, happens when blood flow to the optic nerve drops suddenly. The optic nerve carries visual signals from the eye to the brain, so when it is starved of blood, vision is affected.
NAION typically causes sudden, painless vision loss in one eye. Many people notice it when they wake up in the morning. Vision may look dim, blurry, or partly missing, often in the upper or lower half of what you see.
NAION is uncommon. It affects roughly 2 to 10 people out of every 100,000 each year, and it is most often seen in adults over 50.
What the Research Shows About GLP-1 Drugs and NAION
In May 2026, two groups published the most thorough review of the evidence so far, covering more than 40 studies. They were the American Academy of Ophthalmology and the North American Neuro-Ophthalmology Society (NANOS). Their key findings:
- A possible increase in relative risk. When results were pooled, semaglutide was associated with roughly double the relative risk of NAION. Semaglutide is the active ingredient in Ozempic, Wegovy, and Rybelsus.
- A very small increase in actual cases. Because NAION is so rare to begin with, doubling the risk still means only a small number of additional cases. For example, if 10 people out of 100,000 would normally develop NAION in a year, doubling that would mean about 20 out of 100,000.
- The evidence is mixed. Some large studies found no increased risk at all, including an analysis of 1.2 million patients in the Military Health System. Many studies also relied on billing codes rather than diagnoses confirmed by a neuro-ophthalmologist, which can make the results less precise.
- Cause has not been proven. No biological explanation has been confirmed. Some laboratory research even suggests GLP-1 activity may help protect nerve tissue.
In other words, this is an active area of research. The current data point to a possible association, not a confirmed cause.
What About Tirzepatide (Mounjaro and Zepbound)?
Tirzepatide, the active ingredient in Mounjaro and Zepbound, works a little differently than semaglutide. It is a dual-action medication that activates both GIP and GLP-1 receptors. Because it is now one of the most widely prescribed medications for weight loss, and because it was included in several of the studies reviewed, it deserves its own look.
So far, the findings for tirzepatide are limited and mixed. A large U.S. study of nearly 160,000 adults with type 2 diabetes grouped semaglutide and tirzepatide together and found a modestly higher risk of NAION, although actual cases stayed very rare: about 4 in 10,000 patients over two years, compared with 2 in 10,000 in the comparison group. A separate review of global drug safety reports found no significant link between tirzepatide and NAION.
Because there is less data on tirzepatide, researchers cannot yet say whether its risk is the same as, higher than, or lower than semaglutide. For now, the same practical guidance applies to both medications.
Should You Stop Taking Your GLP-1 Medication?
No, not without talking to your doctor first. If you take semaglutide or tirzepatide and have no vision symptoms, the Academy advises discussing any concerns with your primary care physician before making changes.
For many patients, these medications manage serious conditions such as severe obesity, hard-to-control diabetes, or heart disease. Stopping suddenly can carry more risk than a rare eye event. That is why the Academy and NANOS did not support the European Medicines Agency’s broader recommendation to stop semaglutide whenever NAION is confirmed.
If you do develop NAION while taking semaglutide or tirzepatide, the recommended approach is shared decision-making. You, your eye doctor, and your prescribing physician, such as your primary care doctor or endocrinologist, decide together whether to continue. That decision weighs your overall health, your risk factors, your treatment options, and the risk to your other eye.
Do You Need an Eye Exam Before Starting a GLP-1?
Not specifically for NAION. Current evidence does not show that a screening exam before starting a GLP-1 medication can predict or prevent NAION. For that reason, the Academy and NANOS do not recommend one for that purpose alone.
That said, a few groups should keep eye care on their radar:
- If you have diabetes, keep up with your regularly scheduled diabetic eye exams. These remain essential whether or not you take a GLP-1.
- If you have already had NAION in one eye, you do not need another screening exam, since your risk is already known. Before starting a GLP-1, talk with your doctors about the risk to your other eye. Studies suggest roughly 15 percent of people who have NAION in one eye develop it in the other eye within five years.
Routine comprehensive eye exams are still one of the best ways to protect your vision over time, especially after age 50.
Known Risk Factors for NAION
NAION has well-established risk factors that have nothing to do with GLP-1 medications. People with diabetes are already at higher risk. This makes it harder for researchers to separate the effect of the condition from the effect of the drug.
- Diabetes and high blood pressure, both of which can affect the small blood vessels that supply the optic nerve.
- Low blood pressure overnight, which can reduce blood flow to the optic nerve during sleep. In some patients, taking blood pressure medication in the morning instead of at night can help, under a doctor’s guidance.
- Untreated sleep apnea, which causes repeated drops in oxygen during sleep.
- A small optic nerve cup, a natural anatomical feature sometimes called a “disc at risk.” An eye doctor can see it during a dilated exam.
- Age over 50.
An ophthalmologist can review these factors with you and help you work with your other doctors to reduce the ones that can be managed.
Warning Signs: When to Call an Eye Doctor
Sudden vision loss of any kind should be treated as urgent. Call an ophthalmologist right away if you notice:
- Sudden dimming, blurring, or loss of vision in one eye, even if it is painless
- A dark or missing area in the upper or lower part of your vision
- Vision changes you first notice after waking up
Go to the emergency room immediately if sudden vision loss comes with any of these: a new headache, jaw pain when chewing, scalp tenderness, weakness, numbness, or trouble speaking. These can signal other serious conditions, such as stroke or giant cell arteritis, that need emergency care.
Prompt evaluation matters. It allows your eye doctor to confirm the cause and rule out other conditions. It also lets them coordinate with your physicians about next steps, including your medications.
Our Perspective at Eye Consultants of Delaware
We understand why these headlines are concerning, and we take every question about vision safety seriously. At the same time, GLP-1 medications offer real, well-documented benefits for many patients. The current evidence does not support stopping them out of fear of a rare eye condition.
Our approach is to look at each patient as an individual. You may take a GLP-1 medication, have risk factors for NAION, or have already had vision loss in one eye. In any of those cases, we are happy to review your eye health. We can then share our findings with your primary care physician or endocrinologist so your care team can make the best decision together.
And if you ever experience sudden vision changes, do not wait. Call our Wilmington office the same day.
Frequently Asked Questions
Does Ozempic cause blindness?
There is no evidence that Ozempic causes total blindness. Research shows a possible link between semaglutide and NAION, which usually affects one eye and can cause partial, lasting vision loss. The overall risk remains very low, and a direct cause has not been established.
Do Mounjaro and Zepbound carry the same risk?
Tirzepatide, the active ingredient in Mounjaro and Zepbound, has been included in some studies, but far less data is available than for semaglutide. One large study that grouped the two medications together found a small increase in NAION risk, while a review of global drug safety reports found no significant link for tirzepatide. If you take tirzepatide, the same guidance applies: do not stop on your own, and talk with the doctor who prescribed it about any concerns.
Is vision loss from NAION permanent?
Often, some degree of vision loss remains. Some people regain part of their vision in the months after an episode. However, there is currently no proven treatment that reverses NAION. That is why managing risk factors and getting prompt care matter.
I have diabetes and take a GLP-1. How often should I see an eye doctor?
Most people with diabetes should have a dilated diabetic eye exam at least once a year, or as often as your eye doctor recommends. Taking a GLP-1 does not change that schedule. Still, it is a good idea to let your eye doctor know about all the medications you take.
Questions About Your Medications and Your Eyes? We Can Help
If you take a GLP-1 medication and want to talk through your eye health, our team at Eye Consultants of Delaware is here for you. Call us at 302-998-2333 or book an appointment online through our scheduler.
Source: American Academy of Ophthalmology and North American Neuro-Ophthalmology Society, “What The Data Say About GLP-1 Drugs and Vision Loss,” May 2026.
About the Author: Dr. Heather Dealy
Dr. Dealy is a board-certified ophthalmic surgeon specializing in cataract and glaucoma care. She earned her BA from Bucknell University and her MD from Thomas Jefferson Medical College. After completing her internship at Yale and residency at SUNY Upstate, she completed a glaucoma fellowship at the Scheie Eye Institute, University of Pennsylvania. Practicing in Wilmington, Delaware since 2004, she joined Promise in Sight in 2020 to provide humanitarian eye care in Central America. She is a member of several ophthalmology societies and enjoys racquet sports, gardening, traveling, and reading.
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