GLP-1 Medications and NAION: What We Know About the Potential Vision Risk

Table of contents

1. What is NAION?

2. Why are GLP-1 medications being studied?

3. How large is the potential risk?

4. Semaglutide or the entire GLP-1 class?

5. Association versus causation

6. NAION symptoms

7. NAION risk factors

8. Should patients stop a GLP-1 medication?

9. Eye exams and screening

10. Frequently asked questions

GLP-1 Medications Have Changed Medicine. Now We Are Learning More About Their Effects on the Eye.

Few medication classes have changed the conversation around diabetes and weight management as dramatically as GLP-1 receptor agonists.

Medications such as semaglutide have provided meaningful benefits for many patients. At the same time, whenever a medication begins being used by millions of people, we have an opportunity—and an obligation—to learn more about effects that may have been too uncommon to detect in the original clinical trials.

One of the questions ophthalmologists are now following closely involves a condition called non-arteritic anterior ischemic optic neuropathy, or NAION.

Several observational studies have identified an association between semaglutide use and NAION. More recent research has also examined GLP-1 receptor agonists as a broader class. The important word is association. Research increasingly suggests there may be a real signal, but the magnitude of risk is small, individual risk varies, and not every study has reached the same conclusion. (JAMA Network)

So what should patients actually do with this information?

Not panic.

Not ignore it.

Understand it.

What Is NAION?

The optic nerve is the connection between your eye and your brain. It carries the visual information captured by the retina and allows the brain to interpret what you see.

NAION occurs when blood flow to the front portion of the optic nerve becomes insufficient, resulting in injury to that nerve.

It typically causes sudden, painless vision loss in one eye. Patients may notice blurring, dimming or a missing portion of their visual field, sometimes upon waking. NAION is one of the most common causes of sudden optic-nerve-related vision loss in older adults. (National Eye Institute)

Unfortunately, damage to the optic nerve can be permanent.

That is why sudden vision loss deserves prompt evaluation regardless of whether a patient is taking a GLP-1 medication.

Why Are We Talking About GLP-1 Medications?

The conversation accelerated in 2024 when a study published in JAMA Ophthalmology reported a higher rate of NAION among patients prescribed semaglutide compared with patients receiving other medications for diabetes or obesity.

The investigators were appropriately cautious. Their study demonstrated an association, not proof that semaglutide directly caused the condition. (JAMA Network)

Since then, much larger datasets have been studied.

A 2025 multicenter analysis involving data from millions of patients with type 2 diabetes found additional evidence of an association between semaglutide exposure and NAION, but the estimated increase in risk was considerably smaller than that reported in the original study. (JAMA Network)

Then, in April 2026, investigators analyzing nearly 588,000 U.S. veterans with type 2 diabetes found GLP-1 receptor agonist use was associated with a modest increase in NAION compared with SGLT2 inhibitors. At three years, NAION occurred in approximately 39 per 10,000 GLP-1 users versus 29 per 10,000 SGLT2 inhibitor users—an absolute difference of about 10 cases per 10,000 people. (JAMA Network)

That is an important number because it provides perspective.

A relative increase in risk can sound alarming.

The absolute risk remains low.

Both facts can be true at the same time.

Is This a Semaglutide Problem or a GLP-1 Problem?

We do not have a complete answer yet.

The strongest body of evidence currently involves semaglutide, the active ingredient in medications including Ozempic, Wegovy and Rybelsus.

In June 2025, the European Medicines Agency's safety committee concluded that NAION should be considered a very rare side effect of semaglutide, estimated at up to approximately 1 in 10,000 patients taking the medication. (European Medicines Agency (EMA))

There is also emerging research involving other medications.

A 2025 analysis of patients with type 2 diabetes found that patients prescribed semaglutide or tirzepatide had a higher rate of NAION than matched patients receiving other diabetes medications, although the overall incidence remained low. The authors also noted that previous studies have produced inconsistent results. (JAMA Network)

And this is exactly where we need to be precise.

It would be premature to say:

“GLP-1 medications cause NAION.”

The better statement is:

There is a growing body of evidence suggesting an association—particularly with semaglutide—and the relationship continues to be studied.

Science benefits from precision.

Why Is It So Difficult to Determine Cause and Effect?

This is where the story becomes more complicated.

Many patients taking GLP-1 medications already have conditions associated with NAION.

Diabetes, obesity, hypertension, elevated cholesterol, cardiovascular disease and obstructive sleep apnea have all been associated with NAION risk. (JAMA Network)

And those are also conditions commonly present in people who are prescribed GLP-1 therapies.

That creates an important scientific problem:

Is the medication increasing the risk?

Are the underlying health conditions increasing the risk?

Or are both contributing?

Well-designed observational research attempts to account for those differences, but it cannot eliminate every possible confounding factor.

That is one reason different studies have produced somewhat different estimates.

Should I Stop Taking Ozempic, Wegovy or Another GLP-1 Medication?

For most patients, do not stop a prescribed GLP-1 medication simply because you read about NAION online.

These medications can provide significant benefits for diabetes, obesity and cardiovascular risk, and treatment decisions need to consider the whole patient—not one uncommon potential adverse effect.

The American Academy of Ophthalmology has similarly cautioned against blanket discontinuation of GLP-1 therapy solely because of the possible association with NAION. (AAO)

Instead, talk with the physician who prescribed your medication, particularly if you have significant eye disease, a history of NAION or other risk factors.

Medicine is rarely about asking whether something has any risk.

The more useful question is:

What is the balance of benefit and risk for this particular patient?

What If I've Already Had NAION?

This is a more individualized conversation.

A previous episode of NAION changes the risk discussion because the patient's underlying anatomy and systemic risk factors may already make the optic nerve vulnerable.

That does not mean a patient should independently discontinue a medication.

It means the prescribing physician and eye care team should know the complete history and make a decision together.

The European regulatory recommendation for semaglutide states that treatment should be discontinued if NAION occurs, while U.S. ophthalmology guidance emphasizes individualized discussion between patients and their treating physicians. (European Medicines Agency (EMA))

What Symptoms Should GLP-1 Patients Watch For?

This is perhaps the most practical takeaway.

If you take a GLP-1 medication and experience sudden vision loss or a sudden unexplained change in vision, seek prompt medical evaluation.

Symptoms can include:

• Sudden painless loss of vision in one eye
• Sudden dimming or blurring
• A new dark or missing area of vision
• Loss of part of the visual field
• A significant unexplained difference between the vision in your two eyes

Do not assume a sudden visual change is a medication side effect.

There are multiple retinal, optic nerve and vascular conditions that can cause acute vision loss, and some require urgent treatment.

The symptom tells us something has changed. The examination tells us why.

If you take a GLP-1 medication and are noticing any change in your vision, don't wait for your next scheduled appointment. Contact Wagner Kapoor Institute at 757-481-4400 to be evaluated promptly.

Should Everyone Starting a GLP-1 Medication Get an Eye Exam?

We do not currently have evidence supporting a special NAION screening program for every patient taking a GLP-1 medication.

But if you have diabetes, maintaining appropriate eye care is already important.

And if you have known optic nerve disease, diabetic retinopathy, significant vascular risk factors or a previous history of NAION, it is reasonable to make sure both your prescribing physician and your eye doctor know your complete medical history.

The FDA has also identified NAION as a potential safety signal being evaluated for the GLP-1 receptor agonist class, reflecting the continuing evolution of the evidence. (U.S. Food and Drug Administration)

The Right Response to New Medical Evidence Is Perspective

When new medication risks make headlines, the natural response is to ask:

“Should I be worried?”

I think there is a better question.

“What does this information mean for me?”

For most patients taking GLP-1 medications, NAION remains uncommon. At the same time, the emerging association—particularly with semaglutide—is significant enough that ophthalmologists, primary care physicians, endocrinologists and patients should be aware of it. (AAO)

We will undoubtedly learn more as additional data become available.

Until then, our responsibility is to neither minimize new evidence nor exaggerate it.

Understand the risk. Know the symptoms. Communicate with your physicians. And never ignore a sudden change in vision.

At Wagner Kapoor Institute, we provide advanced ophthalmic care to patients throughout Virginia Beach, Norfolk, Chesapeake, Suffolk, Hampton, Newport News and the greater Hampton Roads region.

If you experience a sudden change or loss of vision, seek prompt medical attention.

To contact Wagner Kapoor Institute, call 757-481-4400.

Sources

• Choi et al., GLP-1 receptor agonists or SGLT2 inhibitors and NAION, JAMA Network Open (2026)

• Heberer et al., new-onset NAION and semaglutide initiation in U.S. veterans, JAMA Ophthalmology (2026)

• PLOS Medicine systematic review and meta-analysis of observational studies (2026)

• U.S. FDA potential safety signals, October–December 2024

• European Medicines Agency: NAION as a very rare semaglutide side effect

• UK MHRA semaglutide and NAION safety guidance (2026)

• Australian TGA GLP-1 RA and rare vision disorder safety update (2026)

Author

Kapil G. Kapoor, MD, FACS, FICS, FASRS Dr. Kapil G. Kapoor, is a board certified ophthalmologist specializing in vitreoretinal surgery. He is Co-Founder and President of the Wagner Kapoor Research Institute which has been actively engaged in over 75 clinical trials, often one of the only sites in the region offering sight-saving treatment. He has been passionately involved in ophthalmology research as part of his mission to deliver the best care possible to his patients. With over a decade’s experience in the field, Dr. Kapoor is a progressive leader in the healthcare space.