Millions of people take GLP-1 drugs like Ozempic and Wegovy for diabetes and weight loss, and most of the conversation has been about what they do for blood sugar and appetite. This week, U.S. regulators added something new to the list of things to know, which is a rare eye condition that can cause permanent vision loss.
The U.S. Food and Drug Administration announced on November 9 that it will require a warning about this possible side effect on the labels of every GLP-1 drug sold in the U.S., Global News reports. That includes Ozempic, Wegovy, Rybelsus, Mounjaro, and Zepbound, whether injected or taken as a pill. The condition is called non-arteritic anterior ischemic optic neuropathy, or NAION, a painless loss of vision caused by reduced blood flow to the optic nerve.
Key takeaways
The FDA now requires a warning about a rare, painless cause of vision loss on every GLP-1 drug label in the U.S.
In an FDA review of 126 trials, the condition occurred in about 6.4 of every 100,000 people taking a GLP-1 for a year, compared with 3.8 among people who were not.
Health Canada is reviewing the same risk for Ozempic, Rybelsus, and Wegovy, but has not changed Canadian labels yet.
Sudden blurriness, a blind spot, or washed-out colours in one eye deserve a same-day check.
Do not stop or change your dose on your own. Talk with the person who prescribes it first.
Why is the FDA adding the warning now?
The FDA began looking into the link after a 2024 study in JAMA Ophthalmology found a higher risk of the condition among people prescribed semaglutide, the drug in Ozempic and Wegovy. The agency then reviewed clinical trials, animal research, and its own reports of side effects, and concluded there is a potential increased risk, while noting that it could not find how the drugs might cause it.
According to the FDA's review of 126 trials, the condition occurred in about 6.4 of every 100,000 people taking a GLP-1 for a year, compared with 3.8 per 100,000 among people who were not. The FDA is now requiring manufacturers to add the risk to the Warnings and Precautions section of every label. European regulators reached a similar conclusion for semaglutide last year and called it a very rare side effect.
Where does Health Canada stand on it?
Canada has its own drug regulator, and Health Canada sets labelling rules here. Global News reports that last month, Health Canada said it had identified a potential safety risk related to Ozempic, Rybelsus, and Wegovy, with this eye condition as the issue under review. Its findings have not been published yet, so there is no Canadian vision loss warning on these labels for now.
The question matters more each month in Canada, since generic versions of semaglutide were authorized this year, as our report on what a generic Wegovy means for Canadians explains.
How rare is the new risk?
Plain numbers show how rare the risk is. The difference in the FDA review was fewer than 3 extra cases for every 100,000 people taking one of these drugs for a year, which sits alongside real benefits for many people living with diabetes or obesity.
For most people, the new vision loss warning changes what to watch for more than whether to take the drug. If you are on a GLP-1, eating less also makes it easier to fall short on protein, which our guide to whether you are eating enough protein covers, and our explainer on how weight-loss drugs work gives the wider picture.
Which vision changes should send you for a same-day check?
According to the FDA, vision changes to watch for include sudden vision loss in one eye, often noticed on waking, blurred or hazy patches, blind spots, and colours that look washed out or distorted. Because the condition is painless, it is easy to brush off, which is exactly why knowing the signs matters.
Not every change in vision points to this. Gradual blurring has many everyday causes, which our guide to blurry vision after 50 walks through, but a sudden change in one eye should be checked the same day.
What should you ask your prescriber?
The new label does not mean you should stop your medication. Bring it up with your prescriber at your next visit, and in the meantime, these steps keep you covered.
Keep taking it as prescribed. Do not stop or change your dose on your own because of this news.
Ask whether the risk applies to you. Your prescriber can weigh your own eye health and other risk factors against the benefits you are getting.
Tell your optometrist. Make sure your eye care provider knows you take a GLP-1, and book a regular eye exam if it has been a while, especially if you have diabetes.
Act fast on sudden changes. Get checked the same day for sudden blurriness, a blind spot, or washed-out colours in one eye.
Report side effects. If you think you had a side effect from any medication, report it to Health Canada, which uses those reports to spot safety problems.
Frequently asked questions
Does the warning cover Mounjaro and Zepbound too?
The FDA's new vision loss warning applies to every GLP-1 drug sold in the U.S., including tirzepatide, the drug in Mounjaro and Zepbound, as well as semaglutide in Ozempic, Wegovy, and Rybelsus. The FDA said cases had been reported with all of the GLP-1 drugs currently on the market.
Should I stop my GLP-1 because of this?
Health experts advise against stopping or changing your dose on your own. The added risk is very small, and these drugs bring real benefits for many people. Talk with your prescriber about your own situation, and if you ever develop sudden vision loss, discuss with your doctor whether to continue the medication.
Is the vision loss permanent?
Vision loss from this condition can be permanent. It often causes lasting vision loss in the affected eye, and there is no proven treatment to reverse it, which is why fast assessment matters. A same-day exam can confirm what is happening, rule out other causes, and guide what to do about your medication next.
Your next step
Have questions about your GLP-1 or a change in your vision? A pharmacist can talk through your medication, and an optometrist can check your eyes. The Medimap Health Hub has more on medications and eye health, and you can book an optometrist near you.
Disclaimer: This article is for general information only and is not medical advice. It does not replace a conversation with a doctor or other qualified health professional who knows your history. If you think you are having a medical emergency, call 911 or go to the nearest emergency department.
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