Millions of people take glucagon-like peptide-1 (GLP-1) receptor agonists like semaglutide and tirzepatide to manage diabetes and obesity. These drugs have transformed weight loss and blood sugar management, but eye doctors are now noticing a potential link between these medications and serious vision problems, including conditions that can lead to blindness.
A study published in JAMA Ophthalmology presents a case series of nine patients who developed significant eye complications after starting GLP-1 drugs. Seven were diagnosed with nonarteritic anterior ischemic optic neuropathy (NAION), a condition that can result in sudden blindness and is caused by reduced blood flow to the optic nerve. One patient developed papillitis, an inflammation of the optic nerve, and one developed paracentral acute middle maculopathy, a type of blood vessel damage in the macula—the part of the retina responsible for sharp vision.
These findings align with other recent studies. Researchers at Massachusetts Eye and Ear, a specialty hospital in Boston affiliated with Harvard Medical School, reported that patients taking semaglutide had a higher likelihood of developing NAION. In Denmark, health officials have called for a European Union investigation after two studies of Danish and Norwegian patients showed similar results.
Bradley Katz, a neuro-ophthalmologist at the University of Utah and lead author of the nine-patient case review, emphasized the need for continued investigation. “Further studies are needed to test our hypothesis. However, this is an important issue for ophthalmologists as we monitor usage of these drugs and how to best be in communication with our patients about them,” he said in a statement.
A Complicated Connection
The findings do not establish that GLP-1 drugs directly cause these eye conditions, but they raise significant questions. All but one of the patients in the case series had a history of type 2 diabetes, a condition that already increases the risk of vision issues. Some researchers speculate that the drugs may contribute to these complications by rapidly lowering blood sugar levels, potentially triggering NAION in susceptible patients.
This idea is supported by previous evidence. Some instances of papillitis have been connected to sudden drops in blood sugar. If GLP-1 medications work too rapidly to correct hyperglycemia, they could indirectly result in optic nerve damage. “In this case series study, it was not possible to establish whether there is a causal link between these drugs and the reported ophthalmic complications,” the researchers wrote. However, they observed that a quick decrease in blood glucose might be linked to these conditions.
Another possibility is that GLP-1 drugs affect vision through a more direct mechanism. Some optic nerve cells have GLP-1 receptors, suggesting that these medications might impact eye function in unexpected ways. If the drugs are influencing these receptors, they could be interfering with normal nerve function and blood flow.
Regardless of the cause, the implications are serious. NAION is a rare but potentially devastating condition, as damage to the optic nerve is often permanent. Even a small increase in risk could impact thousands of people as GLP-1 drugs continue to gain popularity.
What Comes Next?
The uncertainty surrounding these findings makes further research essential. Doctors need a clearer understanding of how GLP-1 drugs might impact vision. If rapid glucose reduction is the trigger, a slower dosing approach could minimize risk. GLP-1 therapy is already typically introduced in escalating doses. However, patients who are more vulnerable to vision problems may need to be identified so that healthcare providers can take additional precautions as needed.
As the use of GLP-1 drugs continues to rise, doctors and researchers will be watching closely. The benefits of these medications are undeniable, but the risks need to be fully understood. Vision is too important to be overlooked.
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