Key Takeaways

• Patients with type 2 diabetes taking semaglutide or tirzepatide had a higher relative risk of developing a rare optic nerve disorder linked to sudden vision loss, though the overall risk remained very low
• Researchers found cases of NAION occurred in 0.04% of patients using the GLP-1 drugs, compared with 0.02% of patients taking other diabetes medications
• The study was observational and does not prove the drugs cause eye damage, but investigators say additional research is needed as use of GLP-1 medications continues to grow

Patients with type 2 diabetes who take the blockbuster weight-loss and diabetes drugs semaglutide or tirzepatide may face a slightly higher risk of developing certain optic nerve disorders, including nonarteritic anterior ischemic optic neuropathy (NAION), according to a large new study published in JAMA Network Open.¹ The overall risk remained very low.

Researchers examined a population-based database of US patient electronic health records of more than 1.5 million patients from December 2017 to January 2023. Models were adjusted by propensity score matching. Eligible patients had type 2 diabetes and no prior diagnosis of eye disorders and were prescribed semaglutide, tirzepatide, or other antidiabetic medications. The study population comprised 159,398 matched patients with type 2 diabetes, including 79,699 patients in the semaglutide or tirzepatide group, and 79,699 patients in the comparison group. 

During the 2-year follow-up, there were 35 patients (0.04%) with NAION in the semaglutide or tirzepatide group and 19 patients (0.02%) with NAION in the matched comparison group (hazard ratio, 1.76 [95% CI, 1.01-3.07]). There were 93 patients (0.12%) with other optic nerve disorders in the semaglutide or tirzepatide group and 54 patients (0.07%) with other optic nerve disorders in the matched comparison group (hazard ratio, 1.65 [95% CI, 1.18-2.31]). No association was found with other disorders of the optic nerve or visual pathways.

NAION is considered the most common acute optic nerve injury in adults over 50. It occurs when blood flow to the optic nerve is reduced, potentially causing sudden and painless vision loss. Diabetes, obesity, hypertension, and sleep apnea are already known risk factors for the condition.

The research comes amid soaring use of GLP-1 receptor agonists, which have transformed treatment for obesity and diabetes because of their effectiveness in lowering blood sugar and promoting substantial weight loss. The drugs have also been associated with cardiovascular and kidney benefits.

Still, the findings add to growing scrutiny over potential side effects linked to the medications. Previous studies examining the connection between semaglutide and NAION have produced conflicting results, and a prior meta-analysis of randomized clinical trials did not find a clear association.

The authors cautioned that their study was observational and cannot prove the drugs directly cause optic nerve damage. They also noted limitations tied to electronic health record data, including possible diagnostic inaccuracies and the inability to measure medication adherence. Researchers said additional studies are needed to confirm the findings, determine whether some patients face higher susceptibility, and better understand the biological mechanisms involved.

Reference

1. Wang L, Volkow ND, Kaelber DC, Xu R. Semaglutide or Tirzepatide and Optic Nerve and Visual Pathway Disorders in Type 2 Diabetes. JAMA Netw Open. 2025;8(8):e2526327. doi:10.1001/jamanetworkopen.2025.26327.