A recent study published in JAMA Ophthalmology suggests a potential connection between semaglutide, a popular medication for type 2 diabetes and weight loss, and a rare eye condition known as nonarteritic anterior ischemic optic neuropathy (NAION). This condition can cause sudden vision loss in one eye due to reduced blood flow to the optic nerve. However, the study does not confirm that semaglutide is the cause, and more research is needed.

The study found that people taking semaglutide were more likely to develop NAION than those using other treatments for diabetes or obesity. However, the researchers noted that the study only shows an association, not causation. In other words, semaglutide might not be the reason for the increased risk. It’s possible that the patients prescribed semaglutide had other health issues that made them more likely to develop NAION.

Experts have pointed out several factors to consider. Some believe the rapid improvements in blood sugar and weight caused by semaglutide might play a role in triggering NAION, rather than the medication itself. Others suggest that people prescribed semaglutide may already have been at higher risk because of underlying conditions like poorly controlled diabetes or severe obesity.

The issue has also drawn attention in Europe. Danish health officials recently reported 19 cases of NAION linked to semaglutide and called for further investigation. Novo Nordisk, the company behind semaglutide, says its own studies show no significant link between the medication and the condition.

While the findings are concerning, experts stress that NAION is very rare and the benefits of semaglutide—such as improved blood sugar control, weight loss, and reduced risk of heart problems—are well-documented. Researchers and health authorities agree that more studies are needed to understand whether semaglutide directly increases the risk of NAION and how to reduce any potential risks for patients.

Update (January 30, 2025)

New research suggests that rapid correction of hyperglycemia, rather than semaglutide itself, could play a role in triggering NAION. This hypothesis is based on case reports where vision loss occurred shortly after starting or restarting the medication. Additionally, other eye conditions, including paracentral acute middle maculopathy (PAMM) and worsening diabetic retinopathy, have been reported in patients using GLP-1 RAs.  

However, the evidence remains inconclusive. Some studies have found an increased risk of NAION, while others have not. Experts caution that selection bias and differences in study design may influence results, and more rigorous research is needed. The American Academy of Ophthalmology advises patients experiencing vision changes while on semaglutide to stop the medication and consult their doctor.  

At this point, study results are pointing in multiple directions, making it difficult to determine a clear cause. If findings were more consistent, we might be closer to identifying whether GLP-1 RAs directly contribute to NAION or if other factors, such as underlying conditions or rapid glucose reductions, are responsible. More research is needed to resolve these uncertainties.

For more information, please visit:

• Fierce Pharma for a short summary.
• Study in JAMA Ophthalmology.
• Invited Commentary for Study in JAMA Ophthalmology.

For more information about the update, please visit:

• Original Investigation in JAMA Ophthalmology.
• Invited Commentary in JAMA Ophthalmology.