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 treatment of diabetes and obesity as dramatically as GLP-1 receptor agonists. Semaglutide and related medications can provide meaningful metabolic and cardiovascular benefits for many patients.

At the same time, widespread use gives physicians and researchers an opportunity—and an obligation—to identify uncommon effects that may not have been apparent in the original clinical trials.

One question ophthalmologists are following involves non-arteritic anterior ischemic optic neuropathy, or NAION. Several observational studies have reported an association between semaglutide or GLP-1 receptor agonist use and NAION. Other evidence, including analyses of randomized trials, has been less conclusive.

For patients in Virginia Beach and throughout Hampton Roads, the practical message is not to panic or stop treatment because of a headline. It is to understand the evidence, know the symptoms and make medication decisions with the physicians who know your health history.

What Is NAION?

The optic nerve connects the eye to the brain. It carries the visual information captured by the retina so the brain can interpret what you see.

NAION occurs when blood flow to the front portion of the optic nerve becomes insufficient, injuring the nerve. It typically causes sudden, painless vision loss in one eye. A patient may notice blurring, dimming, cloudiness or a missing area of vision. The change is sometimes first noticed upon waking.

NAION is called “non-arteritic” because the reduced circulation is not caused by the blood-vessel inflammation seen in arteritic ischemic optic neuropathy. That distinction requires medical evaluation; it is not something a patient can determine at home.

Optic nerve injury from NAION may produce permanent vision loss. Any sudden loss or rapid worsening of vision requires prompt medical attention, whether or not the person uses a GLP-1 medication.

Why Are GLP-1 Medications Being Studied?

The discussion accelerated in 2024, when a retrospective study from a neuro-ophthalmology practice reported a higher rate of NAION among patients prescribed semaglutide than among comparison patients receiving other medications for diabetes or obesity. Because the study came from a specialty referral population and included relatively few events, the authors emphasized that it identified a signal rather than proving causation.

Larger observational studies have since examined the question in broader populations. Their estimates have varied, but several have continued to find a higher rate of NAION in patients using semaglutide or GLP-1 receptor agonists.

Regulatory responses also differ by region. In 2025, the European Medicines Agency concluded that NAION should be listed as a very rare adverse effect of semaglutide. The United Kingdom issued similar semaglutide guidance in February 2026. In July 2026, Australia updated product warnings across GLP-1 medications marketed there. In the United States, the FDA has publicly listed NAION as a potential GLP-1 class safety signal under evaluation; that designation is not the same as a final finding that every medication in the class causes NAION.

How Large Is the Potential Risk?

A 2026 study of nearly 588,000 U.S. veterans with type 2 diabetes compared patients who began a GLP-1 receptor agonist with those who began an SGLT2 inhibitor.

Over three years, NAION was recorded in approximately 39 per 10,000 GLP-1 users and 29 per 10,000 SGLT2 inhibitor users—an absolute difference of about 10 cases per 10,000 people. The study found a relative increase, but the absolute number of events remained low. Its population was also older and predominantly male, which limits how directly the estimate applies to every patient.

That context matters. A relative increase can sound alarming without the absolute numbers. At the same time, a low absolute risk does not make sudden vision loss unimportant.

Both statements can be true:

• NAION is uncommon.

• The potential association deserves awareness and further study.

Is This About Semaglutide or the Entire GLP-1 Class?

The strongest and most consistent evidence currently involves semaglutide, the active ingredient in Ozempic, Wegovy and Rybelsus.

Some newer studies and regulatory actions have evaluated GLP-1 receptor agonists or medications with GLP-1 activity more broadly, including tirzepatide, liraglutide and dulaglutide. However, the evidence is not equally strong for every medication, and differences in the treated populations, doses, formulations and study methods make simple class-wide conclusions difficult.

The most accurate statement today is:

Research supports a possible association between GLP-1 treatment and NAION, with the clearest regulatory and observational signal involving semaglutide. The size, mechanism and class-wide extent of the risk remain under study.

Why Is Cause and Effect Difficult to Prove?

Many people prescribed GLP-1 medications already have conditions linked with NAION, including diabetes, obesity, high blood pressure, elevated cholesterol, cardiovascular disease and obstructive sleep apnea.

That creates a scientific challenge:

• Is a medication contributing to the risk?

• Are underlying metabolic and vascular conditions driving the risk?

• Does individual optic nerve anatomy matter?

• Are several factors interacting?

Observational studies use statistical methods to make comparison groups more similar, but they cannot remove every unmeasured difference. Randomized trials reduce many forms of bias, but NAION is so rare that even large trials may record too few events to provide a definitive answer.

For a deeper explanation of how researchers weigh conflicting evidence, read Does Ozempic Cause Vision Loss? Why Association Is Not the Same as Causation.

What Are the Symptoms of NAION?

NAION usually causes sudden, painless loss or dimming of vision, often in one eye. Symptoms may include:

• Sudden painless vision loss in one eye

• Rapid, unexplained blurring, dimming or cloudiness

• A new dark, gray or missing area in the visual field

• Loss of the upper or lower portion of vision

• A marked, unexplained difference between the two eyes

These symptoms do not automatically mean NAION. Retinal detachment, retinal vascular occlusion, inflammation and other neurologic or ophthalmic conditions can also cause acute visual changes.

The symptom tells us that something changed. The examination helps determine why.

For a focused symptom and action guide, read NAION Symptoms: When Sudden Vision Loss Requires Urgent Care.

Sudden vision change? Do not wait for a routine appointment. Seek urgent ophthalmic or emergency medical evaluation. Patients in Hampton Roads may call Wagner Kapoor Institute at 757-481-4400 for guidance, but emergency symptoms should never be delayed while waiting for an online response.

Who May Have a Higher Baseline Risk of NAION?

Risk does not exist in isolation. Factors associated with NAION include:

• Age, particularly after age 50

• Type 2 diabetes

• High blood pressure

• High cholesterol

• Obstructive sleep apnea

• Cardiovascular or cerebrovascular disease

• Smoking

• Certain optic nerve anatomy, sometimes described as a small or “crowded” disc

• A previous episode of NAION in either eye

Having one or more risk factors does not mean a person will develop NAION or cannot use a GLP-1 medication. It means the benefit-risk conversation should be individualized.

See NAION Risk Factors: Who May Need a More Individualized GLP-1 Discussion? for patient scenarios and questions to discuss with your care team.

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

Do not stop a prescribed GLP-1 medication on your own because of an article or social media post. These medications may provide important benefits for diabetes, obesity and cardiovascular risk. Abruptly changing treatment without a plan can also create risk.

Instead, speak with the clinician who prescribed the medication. Make sure that clinician knows about any history of NAION, optic nerve disease or major vascular risk factors. Your ophthalmologist should also have an accurate medication list, including medications obtained through telehealth or a private weight-management service.

If sudden vision loss occurs, seek urgent evaluation. If NAION is confirmed, medication decisions should be made promptly with the treating clinicians and in light of current product guidance.

What If I Have Already Had NAION?

A previous episode of NAION changes the discussion because it may indicate vulnerable optic nerve anatomy or a combination of systemic risk factors.

It does not create a universal answer for every patient. The reason for GLP-1 treatment, expected health benefit, medication alternatives, control of sleep apnea and vascular risk factors, optic nerve findings and vision in the other eye may all matter.

This is exactly the kind of decision that benefits from communication between the prescribing clinician and the eye care team.

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

There is no universally adopted U.S. recommendation for a special NAION screening examination for every person starting a GLP-1 medication. An examination also cannot predict every future case.

However, routine eye care remains important—especially for people with diabetes—and a baseline or updated examination may be reasonable when a patient has previous NAION, known optic nerve disease, diabetic eye disease or multiple risk factors. The purpose is to understand the patient’s existing eye health, not to promise that screening will eliminate risk.

At Wagner Kapoor Institute, our ophthalmologists evaluate complex retinal, vascular and optic nerve concerns for patients from Virginia Beach, Norfolk, Chesapeake, Suffolk, Hampton, Newport News and communities throughout Hampton Roads.

The Right Response to New Evidence Is Perspective

The evidence surrounding GLP-1 medications and NAION is still evolving. Observational studies and international regulators have identified a meaningful signal, especially for semaglutide. Randomized-trial evidence has not yet produced a definitive answer, in part because NAION is rare.

For most patients, the responsible response is neither alarm nor dismissal.

Understand the potential risk. Know the warning symptoms. Share your complete history with your physicians. Never ignore sudden vision loss.

To schedule a specialty eye evaluation with 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.