Popular diabetes and weight loss drugs like Ozempic and Mounjaro are known for helping people shed those extra kgs, but could they also harm your eyes? Two new JAMA Network Open studies found that semaglutide and tirzepatide may slightly increase the risk of certain eye problems.
Semaglutide belongs to a group of drugs called GLP-1 analogues which works by acting like a natural hormone in the body called GLP-1, that helps control blood sugar and reduces appetite, helping with weight loss. Smaller doses treat type 2 diabetes, while higher doses are used for weight management.
Tirzepatide mimics both GLP-1 and another hormone called GIP, which helps the pancreas release insulin and also plays a role in controlling weight. Both medicines have been game-changers for people with diabetes and those struggling with obesity.
The eye conditions caused by weight loss drugs
The studies focused on two specific eye problems. The first is diabetic retinopathy, where high blood sugar damages the tiny blood vessels in the retina, potentially leading to vision loss or even blindness. The second is NAION, a rare condition in which reduced blood flow to the optic nerve causes sudden, painless loss of vision.
What did the studies find?
In the first study, researchers examined data from people with type 2 diabetes who were taking any GLP-1 medicine (including older versions like dulaglutide and liraglutide) and compared them with people using other diabetes drugs.
Over two years, the researchers found that people taking GLP-1 drugs had a higher risk of both diabetic retinopathy and NAION. However, they were less likely to experience complete blindness or severe complications of diabetic retinopathy, such as bleeding in the eye or abnormal blood vessel growth. In fact, those who already had diabetic retinopathy did not progress to its most advanced stages, and there was also a reduced need for medical, surgical, or laser treatments for eye problems.
The second study, however, focused specifically on people taking the most potent GLP-1 drugs, semaglutide and tirzepatide, and compared them with those on other diabetes medicines like insulin, metformin, or older GLP-1 versions.
Over the two-year study period, researchers noticed a slight increase in cases of NAION, along with a small rise in other optic nerve disorders.
Risks of semaglutide: What did researchers find?
Risks about semaglutide and its impact on eye health have been in question for almost a decade. In early trials, there were signs it might increase the risk of diabetic retinopathy, so doctors began monitoring patients more closely and avoided including those at high risk in some studies. More recently, a small study from one hospital found more cases of NAION in people using semaglutide, which pushed researchers to dig deeper into the possible link.
The European Medicines Agency now lists NAION as an extremely rare side effect affecting about 1 in 10,000 people taking semaglutide.
Should you be worried?
Experts say no one should stop taking these medicines without consulting their doctor. While there is a slight increase in certain eye risks, the benefits of GLP-1 drugs are significant. They don’t just help with diabetes and weight loss, the ongoing research shows they may also protect the heart, kidneys, and liver in people with diabetes or obesity.
What doctors recommend
If you’re starting or already taking semaglutide, tirzepatide, or similar medicines, researchers say it’s important to know the possible risks for your eyes. People who already have diabetic retinopathy should get regular eye check-ups, especially when beginning treatment or increasing their dose. Doctors also recommend raising the dose slowly to avoid sudden changes in blood sugar that could affect vision. Ideally, diabetes specialists and eye doctors should work together to keep a close watch on high-risk patients.
The researchers also believe that future clinical trials for these medicines should include eye safety checks as a standard measure.
GLP-1 drugs like semaglutide and tirzepatide are used to treat diabetes and obesity. But like all medicines, they come with potential side effects. If you’re on these medicines, don’t panic. Instead, talk to your doctor, keep up with eye exams, and watch out for any sudden changes in vision.