Ozempic blindness isn’t a real diagnosis. It’s a nickname used to describe sudden vision loss that may be linked to the weight loss drugs semaglutide (Ozempic, Wegovy) and tirzepatide (Mounjaro, Zepbound).
The main concern is a rare, serious condition called non-arteritic anterior ischemic optic neuropathy (NAION). It can cause permanent vision loss, ranging from mild to severe.
NAION isn’t new. But it’s getting more attention because some people on GLP-1 drugs developed the condition. The numbers are small, but a few recent studies show a possible connection.
Experts say the exact amount of risk isn't known, though it's very low. But there's reason for concern. In one small study, 7 out of 9 people who developed vision problems while taking semaglutide or tirzepatide were diagnosed with NAION. Other research found a slightly higher rate of NAION in people using semaglutide, both for type 2 diabetes and weight loss.
These studies show a possible link between the drugs and vision loss. “They found that the two are related, but that doesn’t mean we understand why,” says Vicente Diaz, MD, Yale Medicine ophthalmologist and assistant professor of ophthalmology and visual science at Yale School of Medicine.
Experts still think most people should take the drugs if needed. The chance of vision loss is very small. And since they may lower your risk of heart disease and other life-threatening conditions, “it makes sense to keep the recommendations as they are,” Diaz says.
Understanding the Risk of Vision Loss From Weight Loss Drugs
GLP-1 drugs like semaglutide help lower your blood sugar, slow your digestion, and curb your appetite. That can lead to weight loss and better health. But they may cause side effects. Researchers are studying their long-term effects, including impact on your vision.
In one 2024 study, researchers found people with type 2 diabetes taking semaglutide were about four times more likely to develop NAION than people with similar health conditions not on the drug. Those with overweight and obesity were about seven times as likely.
Here’s a closer look at the results:
- Among people with type 2 diabetes, 17 out of 710 semaglutide users developed NAION. In the comparison group, only six people did.
- Among those using it for weight loss, 20 out of 979 developed NAION, compared to three in the control group.
While those numbers may sound alarming, the total number of cases is still small. And not all studies found the same link, so the evidence is mixed.
“It’s not 100% clear that the drugs are associated [with NAION],” says Amanda Henderson, MD, chief of the Neuro-ophthalmology Division at the Wilmer Eye Institute and associate professor of medicine at Johns Hopkins School of Medicine. “But there does seem to be some data to suggest that they might be.”
What Is NAION?
It’s an eye condition that can lead to sudden, lasting vision loss. It happens when blood flow to your optic nerve is blocked or reduced.
To understand why that’s a big deal, think of your eyeball like a camera and your brain as a computer. “The optic nerve is the cable that connects the two,” Diaz says.
That cable needs steady blood flow to keep working. If the supply dips, even briefly, your nerve can be damaged. And unlike other tissues, nerves don’t heal well, so the damage is often permanent. “We can replace a lot of body parts, but we don’t know how to replace nerves,” Diaz says.
Experts don’t fully understand what causes NAION, whether you’re on GLP-1 drugs or not. But these health issues may raise your risk:
- Diabetes
- High blood pressure
- High cholesterol
- Obstructive sleep apnea
- Taking certain medications (PDE4 inhibitors)
- Smoking
Eye problems that can increase your risk include:
- Previous NAION in one eye
- A naturally crowded optic nerve (called “disk at risk”)
- Having prior eye surgery
You can still take semaglutide or other GLP-1 drugs if you have these conditions. But if you’ve had eye issues or blood vessel problems, talk to your doctor. They may suggest more frequent vision checks. There’s no proven way to reverse NAION, so early awareness is key.
How might GLP-1 drugs like Ozempic affect your eye?
No one knows for sure, but experts don’t think semaglutide harms your eye directly. The issue likely involves changes in your blood sugar and blood flow.
Lab studies show low blood sugar can trigger proteins that make your eye blood vessels leak. This may weaken the barrier that protects your retina. In theory, a sudden drop in your blood sugar could stress your optic nerve, Henderson says.
Doctors have seen something similar in real life. When you quickly bring your high blood sugar under control, it can sometimes make your diabetic eye disease worse. Some researchers wonder if the same thing might affect the optic nerve in people taking GLP-1 drugs.
“That’s a plausible mechanism,” Henderson says. “But it’s certainly not yet proven.”
Other theories focus on the bigger health picture. Those taking semaglutide often have other health conditions that can raise the risk of NAION.
There’s also a theory that GLP-1 drugs may activate your sympathetic nervous system (your body’s fight-or-flight response). That can narrow your blood vessels, which might limit blood flow to your optic nerve.
Bottom line: We don’t know yet how, or if, GLP-1 drugs cause NAION or other eye problems. But early research points to a possible link.
And while the condition is called Ozempic blindness, it’s not just about Ozempic. Any drug in this class could potentially carry this risk. That’s why it’s important to know the signs.
What Are the Symptoms of Ozempic Blindness?
If you develop NAION, you may have sudden vision changes in one eye. It’s usually painless and affects the lower half of what you see.
One of Henderson’s patients described it this way: “I woke up, and it seemed like I had on my glasses, and there was a smudge over the bottom half of the lens, but it didn’t go away.”
That’s the most common pattern (called inferior altitudinal vision loss), but it’s not the only one. You might lose vision in the center, near your nose, or in curved or patchy areas. It depends on which part of your optic nerve is affected.
Symptoms include:
- Sudden blurry vision
- A dark or gray area in your field of vision
- Trouble seeing colors clearly (called dyschromatoposia)
- A shadowy spot or blind spot
- Loss of peripheral (side) vision
- Loss of contrast or light sensitivity
- A “brownout” or dimming that may come and go
If you notice any of these changes, get emergency care right away. Vision loss from NAION often can’t be reversed, but acting fast may help in some cases. “If there’s something to be done, then the time period to do it is maybe within the first one or two hours,” Diaz says.
Can Ozempic Cause Other Eye Problems?
Yes. NAION isn’t the only eye problem showing up in people taking GLP-1 drugs. While most recent studies focused on NAION, doctors have reported other vision-related issues, too. So when you hear someone say, “Ozempic blindness,” they may be referring to different things.
Other eye conditions may include:
- Papillitis – swelling of your optic nerve
- Paracentral acute middle maculopathy – a rare type of retinal damage
- Wet age-related macular degeneration – new, leaky blood vessels under your retina
In addition, fast changes in your blood sugar (especially when you start a GLP-1 drug) can temporarily affect the shape of your eye. This can cause blurry vision.
When you start taking semaglutide, you may notice a short-term worsening of existing eye conditions, such as:
- Retinopathy (damage to blood vessels in your eye)
- Macular edema (swelling in the center of your retina)
These vision changes usually happen in the first few months of treatment and often improve over time. If you already have an eye condition, your doctor may recommend regular checkups with an ophthalmologist while you’re on a GLP-1 drug.
What’s the Risk of Ozempic Blindness?
After taking a look at current research, the European Medicines Agency said NAION may affect up to 1 in 10,000 people taking semaglutide. But there are no exact numbers on how often it happens in people taking GLP-1 drugs.
“We don’t know what the exact risk is,” Henderson says. “It’s hard to tell if this is truly related to the drug or if it’s just that people with diabetes and obesity are already at risk for NAION.”
Should I be worried about going blind if I’m taking Ozempic?
If you don’t have a history of eye problems, the risk of sudden vision loss while taking GLP-1 drugs like Ozempic is “exceedingly low,” Henderson says.
Uncontrolled diabetes and obesity are risk factors for NAION. They can also raise your chances of other serious eye problems, like diabetic retinopathy, which can also cause blindness.
If you have symptoms like dim or blurry sight, get medical help right away. There may be a short window (one or two hours) to prevent more damage.
Always talk to your doctor about your health risks and needs before you start or stop any drug. They’ll help you weigh the pros and cons of treatment.
Takeaways
Ozempic blindness refers to vision loss that may happen while taking GLP-1 drugs like semaglutide (Ozempic, Wegovy) or tirzepatide (Mounjaro, Zepbound). Some studies show a possible link between these drugs and eye issues like NAION, but the risk is very low. NAION is a rare and serious condition that can cause permanent vision loss. There’s no proof these drugs harm your eye on their own. And most people who take them will not have vision changes.
Ozempic Blindness FAQs
Does semaglutide affect your vision?
Maybe, but more research is needed. Studies show a possible link between semaglutide and NAION, a rare condition that can cause sudden vision loss. However, most people don’t have vision changes on this medication.
What are the long-term side effects of Ozempic?
Side effects include reflux, nausea, vomiting, abdominal cramping, constipation, diarrhea, wrinkles, and sagging skin on your face. Researchers are also looking into possible problems like pancreatitis, gallbladder issues, thyroid tumors, hypoglycemia, kidney failure, and vision changes. On the plus side, semaglutide may help protect your heart when you have diabetes or obesity.
Does vision get better after stopping Ozempic?
There’s no proof Ozempic affects your vision. But if you get NAION while taking it, you can’t reverse your vision loss by stopping the drug.
