Is there a link between weight loss drugs and vision loss?

The use of semaglutide for weight loss and diabetes, which is sold under the popular brand names Ozempic and Wegovy, may be linked to an increased risk of developing an eye condition that can lead to vision loss and blindness, a study published last week in JAMA Ophthalmology.

Compared with people prescribed other types of medications for type 2 diabetes or weight loss, those taking semaglutide were more likely to develop non-arteritic anterior ischemic optic neuropathy (NAION), which occurs when the optic nerve does not get enough blood supply.

What does this mean for people who use (or want to use) semaglutide or another type of weight-loss drug? The study authors cautioned that this was an observational study, meaning that more research is needed to confirm the extent of the increased risk of eye problems in people who take diabetes or weight-loss drugs (or if there is a risk at all). Beyond eye health, the weight-loss drug craze has ushered in a slew of different health connections — some of them positive — and researchers will need more time to iron out those associations definitively.

The JAMA study also did not investigate tirzepatide (brand names Moenjaro or Zepbound), a drug similar to semaglutide, which emerged during the Ozempic and Wegovy wave, but it works slightly differently.

Lead study author Dr. Joseph Rizzo, also director of the Neuro-Ophthalmology Service at Mass General Brigham’s Mass Eye and Ear, called the study’s results “significant but preliminary” in a report from Mass General Brigham press release.

“This is information that we haven’t had before and that we need to factor into the conversations between patients and their doctors, especially if patients have other known optic nerve problems, such as glaucoma, or if there is pre-existing significant vision loss from other causes,” Rizzo said.

Novo Nordisk, maker of Ozempic and Wegovy, did not immediately respond to a request for comment.

This is what we know now.

What is NAION?

NAION is a type of eye stroke that causes vision loss or blindness because there is not enough blood flow to the optic nerve. This nerve is located just behind the eye and carries visual information to the brain.

According to Penn Medicine, the exact cause of NAION is not fully understood, but it is more common in middle-aged or older people, and the shape of a person’s optic nerve may even play a role in the risk of eye stroke. Other risk factors for NAION include high blood pressure, diabetes, and obstructive sleep apnea.

Symptoms include loss of vision in the affected eye, especially upon waking in the morning, usually without pain. Other symptoms include blurred vision, color distortion, a gray or dark spot in your field of vision that doesn’t move, light sensitivity, and loss of peripheral vision. Vision loss may increase or change over a few weeks but should stop progressing after two months, according to the American Academy of Ophthalmologyan association of ophthalmologists and surgeons. There is currently no proven treatment for NAION, according to Penn and the AAO, but reducing your vascular risk factors – physical activity, lowering blood pressure, aiming for healthy blood sugar levels, and more – can help prevent this.

If for any reason you experience loss of vision or severe pain around your eyes, seek immediate medical attention.

Read more: 10 Simple Ways to Protect Your Eyes Every Day

Are weight loss and type 2 diabetes treatment good or bad for your eye health?

In addition to NAION, there is a proven link between diabetes and eye health. Diabetic retinopathya complication of diabetes caused by damaged blood vessels in the back of the eye is the #1 cause of blindness in American adults, according to the American Diabetes Association. It would therefore be logical to think that treat or control diabetes may reduce the risk of diabetic retinopathy, a common cause of vision loss.

The relationship is complicated, however. Some studies have found a potentially negative link between eye health and semaglutide, including one 2017 studywhich found that taking semaglutide may put patients with diabetic retinopathy at increased risk of complications when they first start taking the drug and their blood sugar and insulin levels begin to stabilize. However, in 2023, research presented at the AAO annual meeting found that this link between diabetic eye problems and rapid correction of blood sugar levels is not so important as thought.

In a press release Published Monday about the results of the latest JAMA Ophthalmology study, the AAO noted that previous studies have linked semaglutide to blurred vision, worsening of diabetic retinopathy and macular complications. The eye health organization noted that blurred vision can occur because sudden changes in blood sugar levels can change the shape of the eye, causing blurry vision. The AAO also noted that these changes are usually temporary and go away after a few months.

For some people taking semaglutide or a similar but different class of medicines called tirzepatide (Moenjaro or Zepbound) for medically recommended weight loss, their subsequent risk of developing long-term health problems such as diabetes or heart disease (vascular factors such as blood pressure also affect eye health) can be lowered in the first place. Although some experts have hypothesized that medications such as semaglutide may reduce the risk of eye diseases such as glaucoma in patients who are at higher risk due to BMI, there is not enough evidence to show a strong link between eye health and weight loss at this time, Optometry Advisor reported.

Should I be concerned about my eyes when taking semaglutide?

The AAO is not currently recommending that people stop taking semaglutide; it noted that semaglutide “has been extensively studied” and was approved for medical use in 2017. The AAO also noted that people in the study developed NAION after their first prescription of semaglutide.

You should always discuss with your doctor which medication is right for you and your health, as the “risk versus benefit” profile is different for everyone. If you have a history of eye disease or other risk factors for NAION, it may be a good idea to contact your healthcare provider to ensure that you continue to benefit from your chosen health management plan.

Learn how to protect your eyes every day, the best foods to eat for healthy vision, and why there may be unexpected links between new weight-loss drugs and health outcomes like fertility and sleep apnea.