People taking a popular diabetes medication called semaglutide, sold under brand names like Ozempic, Wegovy, and Rybelsus may face a small but important risk to their vision, according to new research. Semaglutide is often used to help manage blood sugar and support weight loss. However, doctors have become concerned after reports linked it to a rare eye condition that causes sudden and permanent vision loss due to damage to the optic nerve, which is the cable that sends visual information from the eye to the brain.
A group of Scientists led by Professor Anton Pottegård from the University of Southern Denmark and the Norwegian Institute of Public Health explored this possible link. Their research, published on the journal of Diabetes, Obesity and Metabolism, looked at national health records from Denmark and Norway. They studied people who started using semaglutide and compared them with others taking a different kind of diabetes drug that helps remove sugar from the body through urine.
People who took semaglutide were found to be almost three times more likely to develop this serious optic nerve issue compared to those on the other medication. Even so, the actual number of cases was very low. That means while the condition is severe, it happens rarely, and the overall risk for any individual remains low.
Results were similar in both countries and didn’t change much when tested in different ways. “Our study confirms that use of semaglutide is associated with an increased risk of non-arteritic anterior ischemic optic neuropathy, a type of vision loss not caused by inflammation but by reduced blood flow to the eye nerve, but also that the excess absolute risk is low,” said Professor Pottegård. He also noted the risk was higher among people who stayed on the same treatment without switching to another drug.
Some of the research also looked at people who used semaglutide for weight loss instead of diabetes. Although a few cases of vision loss were found in this group too, there weren’t enough to make any clear conclusions. “Although our findings do not rule out the possibility of an increased risk of non-arteritic anterior ischemic optic neuropathy when using semaglutide for obesity, the low number of observed events suggests that any potential risk is likely of limited absolute magnitude,” Professor Pottegård added.
Professor Pottegård’s team used reliable national data and a careful study design, which is the plan for how to conduct the research, to make sure the comparisons were fair. They checked hospital and prescription records to include only relevant cases. Most people who experience this kind of vision loss end up in hospital, so the researchers are confident they included nearly all cases in their study.
“Our findings support an association between use of semaglutide for type 2 diabetes and risk of non-arteritic anterior ischemic optic neuropathy, with a more than two-fold increased hazard ratio,” Professor Pottegård explained. A hazard ratio is a measure used to compare how often a health event happens in one group versus another over time. “However, the absolute risk of this condition remains low among semaglutide users. Analyses of an association between semaglutide for obesity and non-arteritic anterior ischemic optic neuropathy were inconclusive.”
Professor Pottegård and colleagues urged caution when interpreting the results. This type of study does not prove that semaglutide causes the condition—it only shows that the two appear to be linked. They also noted that the number of vision loss cases was too small to understand which groups of people might be at greater risk.
Even with these limitations, this study adds to growing efforts to better understand how safe semaglutide really is. One earlier study raised a similar concern but focused only on patients referred for special eye tests, which may not reflect the average user. The current study gives a broader picture by including everyday users from across the population.
Using semaglutide is becoming more common, not just for managing diabetes but also as a weight loss aid. This makes it even more important to understand any possible risks. Professor Pottegård say that if there is a risk, it must be weighed against the known benefits of semaglutide in helping manage long-term health conditions related to blood sugar. More studies are needed to see if the same pattern appears among people using the drug for weight loss and to explore whether certain individuals are more vulnerable than others.
Journal Reference
Simonsen E., Lund L.C., Ernst M.T., Hjellvik V., Hegedüs L., Hamann S., Jørstad Ø.K., Gulseth H.L., Karlstad Ø., Pottegård A. “Use of semaglutide and risk of non-arteritic anterior ischemic optic neuropathy: A Danish–Norwegian cohort study.” medRxiv, 2024. DOI: https://doi.org/10.1101/2024.12.09.24318574
Image Reference
About the Author
Professor Anton Pottegård is a clinical pharmacologist and pharmacoepidemiologist based at the University of Southern Denmark. With a background in pharmacy and a doctorate in pharmacoepidemiology, he leads research focused on drug safety, real-world medicine use, and the long-term effects of commonly prescribed treatments. His work often draws on large-scale health data to uncover patterns and risks in medication use across populations. Professor Pottegård has contributed extensively to public health by identifying potential side effects of widely used drugs, helping guide safer prescribing practices. He has been involved in international collaborations and advisory roles related to medicine monitoring and regulation. Known for combining rigorous science with accessible communication, he plays a key role in bridging clinical evidence with everyday healthcare decisions. Through his leadership in national registry-based studies, he continues to shed light on the benefits and risks of modern pharmacological treatments.
