About 6% of adults in the United States take GLP-1 agonists for Type 2 diabetes or weight loss.

Because GLP‑1 agonists are becoming more widely used, scientists are now studying an important question: How do these medications affect eye health?

How GLP‑1 Agonists Work

GLP‑1 is a hormone your body naturally makes. Since these medications mimic this natural hormone, they can:

• Reduce appetite and help manage blood sugar
• Help the pancreas release the right amount of insulin
• Slow how quickly food leaves the stomach, which helps you feel full longer

Many GLP‑1 agonists are taken as injections. Common examples include:

• Semaglutide (brand names Ozempic®, Wegovy® and Rybelsus®)
• Dulaglutide (brand name Trulicity®)
• Tirzepatide (brand name Mounjaro®)
• Liraglutide (brand name Saxenda®)

How GLP‑1s May Affect Your Eyes

For most people, GLP-1 agonists are safe and effective. But a small number of people may experience eye-related side effects, especially if they already have certain eye conditions.

Conditions being studied

Scientists are looking at how GLP‑1 agonists impact:

• Progression of diabetic retinopathy, a diabetes-related eye disease that can cause blurriness and blindness

• While initial studies indicated that diabetic retinopathy could worsen while taking this medication, more recent, large-scale data suggests that there is no increased risk.
  
  
• Age-related macular degeneration (AMD), an eye disease that causes loss of sharp vision, making it difficult to see fine details during activities like reading and driving
  
• Studies here also present conflicting findings, but more recent research shows that GLP-1 agonists may actually lower the risk of developing dry AMD. More research is needed to understand whether these medications can help protect against AMD.
  

• Non‑arteritic anterior ischemic optic neuropathy (NAION), a rare but serious condition that affects the optic nerve and can cause permanent vision loss

• NAION is a leading cause of sudden, painless loss of vision in one eye, often described as an “eye stroke.” It affects up to 1 in 10,000 people.
• “Although this side effect from taking GLP-1 agonists is rare, studies show an increased risk of developing NAION in people taking GLP-1 medications,” says Manjot K. Gill, MD, an ophthalmologist at Northwestern Medicine. “There are no known treatments to reverse this type of vision loss.”

• Experts aren’t yet sure why this happens but continue to study this closely. One theory is that a rapid drop in blood sugar could affect the tiny blood vessels that supply the optic nerve.

“More studies are needed to confirm how GLP-1 agonists affect vision and long-term eye health, but being aware of symptoms and keeping up with regular eye exams can help identify these problems early,” says Dr. Gill.

Signs of NAION To Watch For

Contact your eye doctor right away if you notice:

• Sudden vision loss in one eye that doesn’t cause pain
• Missing or dim areas in your side or central vision
• Blurry or hazy vision
• Colors looking faded or less vibrant
• One pupil reacting differently to light
• Swelling of the optic nerve (found during an eye exam)

Dr. Gill says if NAION is confirmed, consult with your full medical team, including your ophthalmologist, neurologist, primary care physician and endocrinologist, to make a well-informed decision on whether to continue or stop the GLP-1 medication.

Who May Be at Higher Risk of Developing Vision Issues?

Many people who start a GLP-1 medication already have certain risk factors. You may have a higher risk of eye-related side effects if you have:

• Existing eye conditions, especially diabetic retinopathy
• Diabetes-related eye disease
• High blood pressure
• High cholesterol
• Sleep apnea

“These conditions may also have an impact on vision, which makes it difficult to fully understand the impact of GLP-1 medications,” says Dr. Gill. “If you have an eye condition, it doesn’t mean you can’t take GLP-1 agonists, but it does mean that regular eye check-ups are especially important since these medications may increase the risk of NAION in some people.”

Your eye doctor may recommend closer follow-up to keep your vision safe.

Balancing Benefits and Risks

For most people with Type 2 diabetes or obesity, the benefits of GLP-1 agonists outweigh the rare eye-related risks. These medications may even help protect the retina. However, because NAION is a possible — though uncommon — side effect, it’s important to pay attention to any vision changes.

“Overall, the findings suggest using caution, not alarm, since most people do well on GLP-1 treatment,” says Dr. Gill. “The health benefits of GLP-1 medications for people with diabetes and weight loss are significant. But anyone experiencing any vision changes should contact their doctor immediately.”

Before Starting GLP‑1 Agonists

• Tell your eye doctor you are starting a GLP-1 agonist and schedule a baseline eye exam before you start taking the medication.
• Ask about A1C goals. A safer, gradual improvement in blood sugar control may lower your risk of extreme changes.
• Know the warning signs and seek care immediately if you develop symptoms.
• Keep up with routine eye screenings, especially if you have an eye condition.

Plan close follow-up with your care team, such as your primary care physician, endocrinologist and ophthalmologist, in the first 12 to 18 months of taking a GLP-1 agonist, especially if your A1C is likely to drop quickly. Your care team may adjust your treatment plan based on your risk factors.