Yes, rare cases of vision issues have arisen in people taking popular GLP-1 weight loss drugs, but the jury's out on whether the medications caused the eye trouble, according to a new small study.
The study reviewed the cases of nine people who developed sight-robbing issues, such as dysfunction in blood vessels around the eye's optic nerve, after taking a GLP-1.
“We’re trying to elucidate if being on these drugs can increase your risk,” said study co-author Dr. Norah Lincoff. She's a neuro-ophthalmologist and professor of neurology at the University at Buffalo.
The study, published recently in JAMA Opthalmology, focused on nine patients, all in their 50s or 60s, who were taking GLP-1s such as semaglutide (Wegovy/Ozempic) and tirzepatide (Mounjaro/Zepbound).
Seven of the nine patients developed a condition known as nonarteritic anterior ischemic optic neuropathy (NAION). This occurs when blood vessels fail to supply enough blood to the optic nerve, which is crucial for sight. In NAION, damage to the nerve can lead to a sudden and permanent partial loss of vision.
Lead study author Dr. Bradley Katz, of the John A. Moran Eye Center at University of Utah Health in Salt Lake City, first noted the issue in a patient who experienced a sudden and painless loss of vision in one eye after starting seamglutide. The patient briefly halted use of the drug, but when they resumed use, vision loss occurred in the other eye.
Alarmed, Katz used a listserve to ask other ophthalmologists if they'd noticed anything similar in their patients. That query resulted in the nine case reports outlined in the new study.
While seven of the nine patients appeared to have NAION, one other patient had developed a "maculopathy"— a blind spot — in their vision after taking a GLP-1. Another developed papillitis, an inflammation of the head of the optic nerve.
The researchers point out that very rare cases of NAION have previously been linked to the use of erectile dysfunction meds or drugs used to ease irregular heartbeats.
On the other hand, common chronic illnesses, such as diabetes, heart disease or obesity, have also been known to help bring on vision trouble. The authors note that all nine patients were taking a GLP-1 because they were battling obesity and/or diabetes.
So it's unclear if the vision troubles were linked to use of a GLP-1 or one of the underlying medical conditions the patients may have had, the researchers said.
It's even possible that, in rare cases, sudden, steep and healthy reductions in blood sugar levels that can come with GLP-1 use might make a person's eyes more vulnerable, Lincoff said.
“So are these drugs increasing the risk for an episode of visual loss?” Lincoff asked. “The message to the patient is that we are still investigating if these drugs put them at higher risk of ischemic optic nerve damage."
As for doctors, she offered this advice: "If a patient on one of these medications calls you and says that there is blurring or vision loss, have them see their ophthalmologist as soon as possible. Don’t wait. Maybe it’s a fluctuation in glucose or it could be something more serious.”
In the meantime, anyone already on a GLP-1 shouldn't panic, the researchers said. Cases of vision trouble linked to the drugs are very rare, but if issues do arise, check with your doctor.
“We have other ways to control diabetes and weight loss,” Lincoff concluded. “There are many options for patients.”