- A new study has found that the GLP-1 drug Wegovy is linked with a higher risk of “eye stroke,” especially in men.
- Ischemic optic neuropathy (ION) is a rare but serious condition that can cause vision loss or even blindness.
- Semaglutide drugs like Wegovy may pose a greater risk of ION than Ozempic due to higher doses used for weight loss.
- Doctors say the risk is small, but there are steps you can take to reduce the risk even further.
A new study has raised concerns about a rare but serious eye condition linked to a popular class of used to treat obesity and diabetes, especially those containing semaglutide.
Ischemic optic neuropathy (ION), known colloquially as an “eye stroke,” can cause sudden vision loss and even blindness.
The study found that certain formulations of semaglutide, particularly Wegovy, the higher-dose version, may carry a higher risk of this vision-threatening side effect, especially in men.
The authors called for further research to better understand the safety of these drugs, which are widely prescribed for weight loss.
This database collects reports from patients, doctors, and drug manufacturers about side effects and complications experienced after taking medications.
The researchers focused on reports where a GLP-1 receptor agonist was suspected to be involved in cases of ischemic optic neuropathy.
Semaglutide comes in different forms, including Ozempic, a weekly injection used primarily for type 2 diabetes; Wegovy, a weekly injection for obesity at a higher dose; and Rybelsus, a daily pill for type 2 diabetes.
The study examined each formulation separately to see if the risk of vision problems differed. They also looked at tirzepatide, a newer drug that works on similar pathways but in a slightly different way, as well as common diabetes medications like metformin and insulin for comparison.
The team used statistical methods designed to detect whether a particular drug was reported more frequently with ischemic optic neuropathy than would be expected by chance.
They also adjusted their analysis to account for differences in age and sex, helping to clarify whether certain groups might be more vulnerable. This approach allowed researchers to identify patterns in the data despite the rarity of the condition and the complex background of patients using these drugs.
Out of the tens of millions of reports examined, about 31,000 involved semaglutide.
The obesity drug Wegovy showed the strongest link to ischemic optic neuropathy, even though it had fewer overall reports than Ozempic, the diabetes formulation.
The higher dose of Wegovy likely plays a role, as it leads to greater systemic exposure and faster weight loss, which might affect blood flow to the optic nerve.
Males appeared to be at higher risk than females, with the data showing a notably stronger association in male patients taking Wegovy.
No cases were reported with the oral form of semaglutide (Rybelsus), which is absorbed more slowly and in smaller amounts, suggesting that the way the drug is delivered and its dose matter.
Tirzepatide, another drug in this class but with a different mechanism, showed no significant association with vision problems despite achieving even greater improvements in blood sugar and weight. This may be because tirzepatide acts on two receptors, potentially balancing out effects on blood flow and reducing the chance of ischemic injury to the optic nerve.
The study also found no increased risk with other commonly used diabetes medications like metformin and insulin. This specificity points toward a unique effect of semaglutide, especially at higher doses, rather than a general risk from improving blood sugar or losing weight.
Researchers believe that high dose semaglutide may reduce blood flow to the optic nerve through factors such as fluid loss, low blood pressure — especially at night — and shifts in the body’s vascular system. These changes could make the optic nerve more vulnerable to damage. However, the exact biological link remains to be confirmed in future studies.
Because the FDA’s database relies on voluntary reporting, the numbers do not reflect how often the problem actually occurs. Still, the clear pattern seen with Wegovy and the higher risk in men suggest that doctors should monitor patients carefully, especially those receiving the higher doses for obesity.
More detailed studies are needed to understand who is most at risk and how to prevent this serious complication.
Hector Perez, MD, a board certified bariatric surgeon at Renew Bariatrics and an advisor at BestSurgeons.com, who was not involved in the study, said that while the risk for ION is worth monitoring, the study is very small.
“Untreated obesity, diabetes, and vascular disease damage vision far more commonly than semaglutide does,” he told Healthline.
However, Perez noted that there are still several steps you can take to reduce your risk for this side effect.
He advised that you avoid extremely rapid early weight loss. “Gradual caloric reduction helps prevent sudden drops in blood pressure or perfusion,” he said.
Perez further stated the importance of staying well hydrated, explaining that when people’s appetites are suppressed, they often tend to reduce their fluid intake as well. However, this can worsen optic nerve perfusion, he said.
“Excessively low nocturnal BP is a known risk factor for optic nerve ischemia,” he cautioned.
Diala Alatassi, MD, an obesity medicine physician at TeleSlim Clinic, who was also not a part of the study, added that if you have multiple health conditions along with obesity, it’s wise to start low and titrate your dose up slowly.
She further noted that it’s best to consult with an experienced weight loss doctor rather than purchasing medications online and self-titrating.
Alatassi recommended staying up to date with your eye health. “Patients, especially diabetics, should get yearly eye exams to get a baseline prior to starting such medications,” she said.
Finally, Alatassi, stressed the importance of always following your doctor’s instructions.
“These are prescription medications,” she said. “Just like other medications, if used inappropriately, they can have unfortunate outcomes.”
