Study links popular diabetes drugs to serious eye disorder

Patients using semaglutide, found in medications like Ozempic and Wegovy, might have a higher chance of developing a serious eye condition known as non-arteritic anterior ischemic optic neuropathy (NAION).

This is according to a recent study by researchers from Mass General Brigham and Harvard Medical School, which notes that the condition can lead to sudden vision loss and even blindness in severe cases.

Published in July 2024 in JAMA Ophthalmology, the study analysed patients taking Ozempic and Wegovy who were more likely to develop NAION.

The researchers reviewed records from patients who hadn't had NAION before and were seen by eye specialists between 2017 and 2023. The study reviewed records from over 16,800 patients in Boston, focusing on 1,700 with diabetes, overweight, or obesity. It compared those using semaglutide with those who weren't over 36 months.

According to the research, among 200 diabetes patients using semaglutide, 17 developed NAION, which was four times more than those not using the drug. In the obesity group, 20 out of 361 patients on semaglutide developed NAION, a rate seven times higher than those not on the drug.

However, the findings were refuted by Novo Nordisk, the maker of these medications, which said the study was not enough to prove semaglutide causes NAION.

"We prioritise patient safety and take reports of side effects seriously," the company noted.

Doctors have seen cases where patients using semaglutide developed NAION, but they caution against concluding that the drug directly causes this condition and stress the need for a large, well-controlled study to establish a clear link.

NAION is a significant concern because it's the second most common optic nerve disease in the U.S., affecting up to 10 in 100,000 people and a leading cause of sudden blindness. Dr. Joseph Rizzo, the study's lead author, described NAION as a "stroke of the optic nerve." It's a permanent condition with no known treatment.

Dr. Rizzo emphasised that because the study was observational, it cannot definitively prove semaglutide causes NAION, hence the need for a large-scale, controlled study to confirm any connection.

Dr. Andrew Lee, a neuro-ophthalmologist, noted that while some patients on semaglutide developed NAION, it's unclear if this is a direct cause. People with Type 2 diabetes already face higher risks of eye problems like NAION and diabetic retinopathy, a leading cause of blindness.

Other factors like sleep apnea and hypertension, common in obese people, also raise NAION risks, and complicate the study's findings, underscoring the need for caution and more research as the study only shows a connection, not a definite cause.