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Optic Nerve Health

Understanding the numbers

GLP-1 medicines and the risk of NAION

Reviewed by James Deom, OD, MPH, FAAO, Chief of Eye Care Services. Last reviewed: November 11, 2026.

Most of what we know comes from observational studies of health records. These can show a link but cannot prove cause and effect. Results vary by who was studied, what medicine they were compared with, and how NAION was counted. Here’s how to read them. For a full side-by-side table, including areas of agreement and disagreement, see Comparing the major studies.

How to read the numbers

  • Rate per 100,000 per year: how many people out of 100,000 develop NAION in a year.
  • Relative risk / hazard ratio (HR): how many times higher the risk is compared with another group. HR 2 means “twice the risk,” but twice a very small number is still small.
  • Absolute risk difference: the actual number of extra cases. This is usually the most useful number for a personal decision.

How common NAION is to begin with

  • About 2.3 to 10.2 per 100,000 per year, mostly in adults over 50. It’s slightly more common in men and peaks around age 60.¹
  • In a South Korean nationwide study, about 103 per 100,000 adults 40 and older had had NAION at some point (prevalence).²

Factors linked to higher or lower risk (large U.S. insurance study)³

Factor Reported association
Each additional year of age About 2% higher risk
Women compared with men About 36% lower risk
Latino compared with White ancestry About 46% lower risk
High blood pressure HR 1.62
Blood-clotting disorders HR 2.46
Diabetes with organ complications vs. uncomplicated diabetes HR 1.27
Retinal vein occlusion HR 3.94
Macular degeneration HR 1.29

What studies found in people taking GLP-1 medicines

Studies that found a higher risk with semaglutide

  • First report (2024, a Boston neuro-ophthalmology referral clinic): in people with diabetes, 8.9% vs 1.8% over 3 years (HR 4.28); in people with obesity, HR 7.64.⁴ Patients at a specialty referral clinic have higher risk than the general public, so these numbers are higher than later, larger studies found.
  • Denmark and Norway national registries: about 2.2 to 2.8 times the risk.⁵ ⁶ In Denmark, the median time from starting semaglutide to NAION was about 22 months.⁵
  • Adults 65 and older with diabetes (U.S. Medicare research letter): semaglutide HR 1.39 (95% CI 1.13–1.72) compared with other second-line diabetes medicines.⁷
  • A 2026 review pooling 5 studies: HR 2.17, an absolute extra risk of about 0.014% per year, or about 1 extra case per 7,000 people per year.⁸
  • Another 2026 review: about 2.5 times overall, and 2.41 times in people with diabetes.⁹

GLP-1 medicines as a group

  • UK study compared with DPP-4 inhibitors (another diabetes pill): 18.5 vs 7.2 per 100,000 in the first year (about 11 extra cases per 100,000). Risk was highest in the first 6 months and was higher in people under 50, men, smokers, and those whose A1c dropped by 1% or more.¹⁰
  • Semaglutide or tirzepatide (studied together): HR 1.76.¹¹ This study couldn’t separate the two drugs.
  • FDA’s review of 126 clinical trials: 6.4 vs 3.8 cases per 100,000 person-years. Only 15 probable cases occurred among more than 134,000 trial participants.¹²

Studies that found little or no added risk

  • A Swedish nationwide study found that most of the extra risk disappeared when people with similar diabetes severity were compared. This suggests other health differences explain part of the link.¹³
  • A 2024 multinational study (Chou and colleagues) found no statistically significant increase with semaglutide in type 2 diabetes, in obesity, or in both.¹⁴
  • Some large U.S. record studies also found no significant increase, including a matched TriNetX analysis. A 14-database research network found mostly non-significant differences in its main comparisons and only a modest increase (about 1.3 times) in a second type of analysis.¹⁵ In addition, a 2026 review in Ophthalmology found no consistent overall increase once results were adjusted.¹⁶
  • A U.S. Military Health System study of about 1.2 million adults, noted by AAO and NANOS, did not find a higher NAION risk with semaglutide; in people with type 2 diabetes the observed odds were actually lower. That unexpected result may reflect confounding or who was prescribed the medicine, and it should not be read as proof that the drug protects the optic nerve.¹⁷

Why the evidence is hard to interpret

  • People prescribed GLP-1 medicines often already have more NAION risk factors, such as diabetes, sleep apnea, and high blood pressure.
  • Diagnosis codes in health records are sometimes wrong, and NAION can be confused with other conditions.
  • NAION is rare, so even huge studies have few cases, which makes the estimates less precise.
  • The FDA reported that animal studies have not identified a mechanism by which these medicines would cause NAION.¹²

What regulators and professional groups say

Recommendations are not identical. See also the fuller table on the study comparison page.

Group Position (short version)
FDA (Nov 9, 2026)¹² All GLP-1 labels must mention a potential increased risk of rare NAION. After NAION, consider stopping the medicine unless the benefits clearly outweigh the risk.
European Medicines Agency (June 2025)¹⁸ NAION is a “very rare” side effect of semaglutide (up to 1 in 10,000). Stop semaglutide if NAION is confirmed.
American Optometric Association (June 2025)¹⁹ Comprehensive dilated exam within 12 months before starting, or a baseline exam within one month after.
American Academy of Ophthalmology and NANOS (2026)¹⁷ Do not recommend a routine exam solely to predict NAION. Keep diabetic eye exams on schedule. If NAION occurs, use shared decision-making rather than automatically stopping the medicine.

All four agree that sudden vision changes need prompt evaluation.

Dr. Deom’s recommendation (his clinical opinion / practice recommendation)

Dr. James Deom recommends that everyone starting or taking a GLP-1 medication have a comprehensive dilated eye exam with OCT, OCT angiography (OCTA), and retinal photography (fundus photos with autofluorescence) as a baseline and for follow-up, and seek same-day care for sudden vision loss.

This is his opinion and practice recommendation, not a society mandate.

Why he recommends each test — to keep a record, not to predict NAION:

  • OCT is a scan that measures the thickness of the nerve-fiber and ganglion-cell layers and shows the shape of the optic nerve, so there is a baseline to compare if vision changes later.
  • OCT angiography (OCTA) is a scan that documents blood flow around the optic nerve and in the central retina (the macula), as a baseline record.
  • Retinal photographs, including autofluorescence, record how the optic nerve and retina look, including whether the disc is crowded or has drusen, and can show other retinal disease.

These tests have not been shown to predict or prevent NAION. Eye-specialist groups (the American Academy of Ophthalmology and the North American Neuro-Ophthalmology Society) do not recommend an exam only to try to predict NAION, and a normal exam cannot rule out future NAION. Dr. Deom still recommends this exam and imaging as his practice approach so that a baseline exists, other eye conditions can be found, and the appearance of the optic nerve is documented.

Dr. James Deom’s personal clinical thought

This is his opinion, not established evidence. It is not a finding from the studies or a position of the FDA, EMA, AAO, NANOS, or AOA.

As people lose weight and get healthier on GLP-1 medicines, their blood pressure and cholesterol medicines are often not reviewed or adjusted. Blood pressure treatment that is no longer matched to a person’s needs may lead to low blood pressure (hypotension). Low blood pressure can be more pronounced at night and could reduce blood flow to the optic nerve during sleep. That possibility would fit the typical way NAION presents: vision loss noticed on waking.

Dr. Deom recommends that people taking a GLP-1 medicine also work on exercise and diet, and keep regular visits with their usual doctors — even if that doctor did not prescribe the GLP-1 — so the rest of their care, including blood pressure, is maintained. Do not start, stop, or change a blood pressure or cholesterol medicine on your own; talk with the clinician who prescribes it.

Putting it in perspective

Several observational reviews suggest about 1 to 2 additional NAION cases per 10,000 people treated with semaglutide for a year.⁶ ⁸ That’s a study estimate, not a personal prediction. The benefits for diabetes, weight, and certain heart, kidney, and sleep apnea conditions can be substantial. The right balance depends on your medicine, why you take it, and your health history. Please don’t combine these different numbers into a single personal risk. Your doctors can help put them in context.

A comprehensive eye exam can find existing eye disease and guide follow-up, but no scan or exam schedule has been proven to predict or prevent NAION. All five offices have OCT, OCT angiography (OCTA), and fundus photography with autofluorescence, the imaging set in Dr. Deom’s recommendation above. Common questions, including whether to stop a medicine, are on the GLP-1 patient page.

  • Hazleton Eye Specialists: 281 Airport Road, Hazle Township, PA 18202 · 570-453-2020
  • Stroudsburg Eye Specialists: 2942 Route 611, Suite 5, Tannersville, PA 18372 · 570-421-3342
  • Nanticoke Eye Specialists: 233 S. Prospect St., Nanticoke, PA 18634 · 570-735-6000
  • Pottsville Eye Specialists: 541 West Bacon Street, Pottsville, PA 17901 · 570-628-3937
  • Bangor Eye Specialists: 385 Bangor Junction Rd., Bangor, PA 18013 · 610-588-0129

All locations →

Medical disclaimer. This page is for general education only. It is not medical advice and does not replace an examination or a conversation with your own doctors. Do not start, stop, or change any medicine without talking to the clinician who prescribes it. If you have sudden vision loss, seek same-day care from an eye doctor or an emergency department. Information is current as of the “last reviewed” date and may change as new research is published.

References

  1. Gabbay et al. PLoS One. 2024. https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0313098 (and FDA DSC, ref 12)
  2. Prevalence and incidence of NAION in South Korea. Br J Ophthalmol. 2018;102(7):936. https://bjo.bmj.com/content/102/7/936
  3. Cestari DM, et al. Ophthalmology. 2016. https://pubmed.ncbi.nlm.nih.gov/27659545/
  4. Hathaway JT, et al. JAMA Ophthalmol. 2024;142(8):732-739. https://jamanetwork.com/journals/jamaophthalmology/fullarticle/2820255
  5. Grauslund J, et al. Int J Retina Vitreous. 2024. https://link.springer.com/article/10.1186/s40942-024-00620-x
  6. Danish–Norwegian cohort. Diabetes Obes Metab. 2025;27(6):3094-3103. https://pubmed.ncbi.nlm.nih.gov/40098249/
  7. McDonald CJ, Fung KW. GLP-1 RAs and risk of NAION in older patients with diabetes. JAMA Ophthalmol. 2025. https://jamanetwork.com/journals/jamaophthalmology/fullarticle/2836771
  8. Chrzanowski J, et al. PLoS Med. 2026;23(5):e1005064. https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1005064
  9. Dhivagaran T, et al. Neurology. 2026;106(10):e214864. https://www.neurology.org/doi/10.1212/WNL.0000000000214864
  10. Noh Y, et al. Diabetes Care. 2026;49(5):763-771. https://diabetesjournals.org/care/article/49/5/763/164499/
  11. Semaglutide or tirzepatide and optic nerve disorders in T2D. JAMA Netw Open. 2025. https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2837377
  12. U.S. FDA Drug Safety Communication, Nov 9, 2026. https://www.fda.gov/drugs/drug-safety-communications/fda-requires-safety-labeling-changes-glucagon-peptide-1-receptor-agonists-glp-1-ras-due-potential
  13. Ueda P, et al. Ann Intern Med. 2026;179(9):1232-1243. https://www.acpjournals.org/doi/10.7326/ANNALS-25-02096
  14. Chou CC, et al. Association between semaglutide and NAION: a multinational population-based study. Ophthalmology. 2024. https://www.aaojournal.org/article/S0161-6420(24)00685-7/fulltext · Also: Abbass NJ, et al. TriNetX matched cohort. Am J Ophthalmol. 2025. https://www.ajo.com/article/S0002-9394(25)00094-7/fulltext
  15. Cai CX, et al. (OHDSI). JAMA Ophthalmol. 2025. https://jamanetwork.com/journals/jamaophthalmology/fullarticle/2830475
  16. Semaglutide and the risk of NAION: meta-analysis. Ophthalmology. 2026. https://www.aaojournal.org/article/S0161-6420(26)00082-5/fulltext
  17. AAO & NANOS. What the data say about GLP-1 drugs and vision loss. Sep 22, 2026. https://www.aao.org/newsroom/news-releases/detail/what-data-say-about-glp-1-drugs-vision-loss · Military Health System study: Lieberman RA, et al. Mil Med. 2026;191(5-6):e1020. https://academic.oup.com/milmed/article/191/5-6/e1020/8320596
  18. EMA PRAC, Jun 6, 2025. https://www.ema.europa.eu/en/news/prac-concludes-eye-condition-naion-very-rare-side-effect-semaglutide-medicines-ozempic-rybelsus-wegovy
  19. AOA clinical report, June 2025. https://www.aoa.org/AOA/Documents/Practice%20Management/Clinical%20Guidelines/AOA%20GLP-1_EBO_clinical-report.pdf