Australians using popular weight-loss and diabetes medications including Ozempic, Wegovy and Mounjaro are being urged to watch for sudden vision changes after the country's medicines regulator issued a formal safety warning linking the drugs to a rare eye disorder that can cause permanent blindness.
The Therapeutic Goods Administration (TGA) has flagged a condition known as non-arteritic anterior ischaemic optic neuropathy (NAION) — a disruption to blood flow in the optic nerve that can lead to sudden, irreversible vision loss. The regulator stressed that once the condition develops, no treatment has been shown to restore sight.
Which medicines are affected and how common is the risk?
The warning covers the class of drugs known as GLP-1 receptor agonists (GLP-1 RAs), which are widely prescribed for type 2 diabetes and obesity. The medicines named include Ozempic, Wegovy, Mounjaro, Trulicity and Saxenda — household names that have gained widespread public attention in part due to their significant weight-loss effects.
According to the TGA's Database of Adverse Event Notifications, 36 cases of optic ischaemic neuropathy have been reported in Australia among people taking GLP-1 medicines. Of those, 23 involved semaglutide (the active ingredient in Ozempic and Wegovy), 10 involved tirzepatide (Mounjaro), and three involved liraglutide (Saxenda). No cases were directly linked to dulaglutide (Trulicity), though one patient who developed the condition while taking semaglutide had previously used that drug.
Optometry Australia's chief clinical officer described the overall risk as rare, noting it may affect up to one in 10,000 users. He emphasised that GLP-1 medicines continue to deliver meaningful health benefits for many people managing diabetes and obesity, and that the warning should not be read as a reason to stop medication without medical guidance.
What the TGA is telling patients and doctors
The regulator is urging anyone taking one of the listed GLP-1 medicines to remain alert to any sign of vision change. Its advice is direct: "If any changes are noted, stop using the medicine and seek prompt medical attention."
Health professionals have separately been advised to instruct their patients to seek urgent medical care if they experience sudden or partial vision loss. NAION typically presents as sudden, painless vision loss, often affecting one eye — a presentation that can easily be mistaken for something less serious.
Updated safety information for Ozempic and Wegovy now notes that some studies suggest an increased risk of NAION, although regulators have identified no specific time interval after which the condition might develop following the start of treatment.
Who may be at greater risk?
The TGA has highlighted that people born with a particular optic nerve structure — referred to as a "disc at risk" — face an elevated likelihood of developing NAION. This structural feature can be detected during a comprehensive eye examination carried out by an optometrist or ophthalmologist, meaning a routine eye check could identify those most vulnerable before any symptoms appear.
A range of pre-existing health conditions are also considered established risk factors for the disorder. These include diabetes, cardiovascular disease, high blood pressure, high cholesterol, obstructive sleep apnoea and smoking — conditions that overlap significantly with the patient populations most likely to be prescribed GLP-1 medicines in the first place.
What patients should watch for
Clinical experts say it is entirely reasonable for patients to seek reassurance from their doctor or eye care provider following the TGA's warning. Key warning signs to watch for include:
- Sudden loss of vision in one or both eyes
- Partial vision loss or a darkened area in the visual field
- Any unexplained change in eyesight, even if painless
Anyone experiencing these symptoms while taking a GLP-1 medicine should stop the medication and seek urgent medical attention immediately, in line with the TGA's guidance.
