Recent research suggests GLP-1 receptor agonists, popular medications for type 2 diabetes and weight loss, may carry a small increased risk of a rare eye condition called nonarteritic anterior ischemic optic neuropathy (NAION). However, two major studies published in the Annals of Internal Medicine emphasize that while the relative risk increased, the actual number of people affected remains extremely low, and the medications' proven benefits for heart health, kidney function, and blood sugar control continue to outweigh this potential concern.

What Is NAION and How Does It Relate to GLP-1 Use?

NAION is an uncommon eye condition that causes sudden, painless vision loss when blood flow to the optic nerve is disrupted. It is the most common form of optic neuropathy in adults over age 50. Researchers have been investigating whether GLP-1 drugs, which include medications like semaglutide (found in Ozempic and Wegovy), might increase the risk of developing this condition.

A U.S. study led by researchers at Rutgers University analyzed healthcare data from more than 18,000 adults aged 18 to 65 with type 2 diabetes who started glucose-lowering medication. When comparing people taking GLP-1 drugs to those taking other diabetes medications such as SGLT-2 inhibitors or DPP-4 inhibitors, the GLP-1 group showed a higher relative risk of developing NAION over an 18-month period.

A separate Swedish study examined nationwide healthcare data from over 293,000 adults aged 35 to 84 with type 2 diabetes between 2013 and 2024. Researchers compared people who started GLP-1 drugs with those who started SGLT-2 inhibitors and found similar results: a higher relative risk among GLP-1 users, though the absolute risk remained very low in both groups.

How Rare Is This Vision Loss Risk in Real Numbers?

The key takeaway from both studies is understanding the difference between relative risk and absolute risk. While the relative risk appeared to double in some comparisons, the actual number of people affected was remarkably small. In the U.S. study, the increased risk over 18 months amounted to approximately three to four additional cases per 10,000 patients treated with GLP-1 medications. This translates to roughly one additional case for every 2,778 to 3,333 patients treated.

The Swedish study found similar numbers: after one year of follow-up, the risk of NAION was 0.04% among people taking a GLP-1 medication and 0.02% among those taking an SGLT-2 inhibitor. In practical terms, this corresponds to approximately four cases per 10,000 people taking a GLP-1 drug over one year, compared with two cases per 10,000 people taking an SGLT-2 inhibitor.

"Patients and physicians should interpret these numbers as a demonstration that the risk of having NAION can increase with use of a GLP-1 receptor agonist medication. The risk, however, is still quite low," said Benjamin Bert, a board-certified ophthalmologist at MemorialCare Orange Coast Medical Center.

Benjamin Bert, MD, Board-Certified Ophthalmologist at MemorialCare Orange Coast Medical Center

The U.S. study also found that the signal was concentrated among adults aged 50 to 65 years and men, who accounted for approximately 85% and 70% of events, respectively. This suggests that certain groups may face a slightly higher risk than others.

What Should People Taking GLP-1 Medications Do?

Both research teams emphasized that their findings should not change current prescribing practices or prompt people to stop taking these medications. The researchers noted that the studies were observational, meaning they cannot prove that GLP-1 drugs directly caused the increase in risk. Instead, the findings may highlight underlying differences between people taking GLP-1s and those taking other diabetes medications, such as more advanced cardiovascular risk factors that are independently associated with optic nerve disease.

"I would not recommend stopping a GLP-1 medication solely because of this study. These medications have substantial benefits for diabetes, cardiovascular disease, kidney disease, and weight management, and the potential excess risk identified in our study was very small," explained Chintan Dave, Associate Professor of Pharmacy and Epidemiology at Rutgers Ernest Mario School of Pharmacy and Rutgers School of Public Health.

Chintan Dave, PharmD, PhD, Associate Professor of Pharmacy and Epidemiology at Rutgers Ernest Mario School of Pharmacy and Rutgers School of Public Health

Steps to Monitor Your Vision While Taking GLP-1 Medications

Although the risk of vision problems remains very low, experts recommend staying alert to any changes in your eyesight. Here are key warning signs and preventive steps:

• Sudden Vision Changes: Watch for dimming or blurring in one eye, loss of part of the visual field, or sudden vision loss. These symptoms warrant urgent, same-day evaluation by an ophthalmologist or emergency department visit.
• Regular Eye Exams: Maintain routine eye appointments with your eye care provider, especially if you are in a higher-risk age group (50 to 65 years) or are male, as these groups showed slightly elevated risk in the studies.
• Open Communication with Your Doctor: Discuss any vision concerns with both your endocrinologist and eye doctor. They can help determine whether your symptoms are related to your GLP-1 medication or another cause.
• Ongoing Monitoring: Continue taking your GLP-1 medication as prescribed unless your doctor advises otherwise. The proven benefits for blood sugar control, weight loss, and cardiovascular health remain substantial.

The research also highlights the importance of understanding that further investigation is still necessary to fully clarify the association between GLP-1 use and NAION risk, as well as the role of confounding variables that may influence the findings.

Why Do These Medications Remain Beneficial Despite the Risk?

GLP-1 receptor agonists are a class of medications that work by mimicking a hormone called glucagon-like peptide-1, which helps regulate blood sugar levels. For people with type 2 diabetes, these drugs offer multiple proven benefits: improved blood glucose control, weight loss, and significant reductions in the risk of cardiovascular disease and kidney disease.

Type 2 diabetes accounts for approximately 90 to 95% of all diabetes cases worldwide. It develops when the body's cells become less responsive to insulin (a condition called insulin resistance) and the pancreas gradually struggles to keep up with the increased demand for insulin. Over time, the pancreas may produce less insulin than the body needs.

The condition is strongly associated with overweight and obesity, physical inactivity, age, family history, and certain ethnic backgrounds. South Asian populations, including people of Indian origin, have a particularly high risk and tend to develop type 2 diabetes at lower body weights and younger ages than some other populations.

For most people with type 2 diabetes, the study authors conclude that the proven benefits of GLP-1 drugs substantially outweigh the potential safety signal identified in these studies. The key is maintaining open communication with your healthcare team and staying alert to any unusual vision changes while continuing to benefit from these effective medications.