In recent months, weight-loss injections such as Mounjaro (tirzepatide) and Ozempic (semaglutide) have gained widespread popularity—not just among people managing type 2 diabetes but also those seeking substantial weight reduction. However, growing medical reports suggest these GLP‑1 receptor agonists may carry a small—but concerning—risk of serious eye complications, including age-related macular degeneration (AMD) and optic neuropathy. Here’s what recent findings and health agencies are saying.
1. The Canadian Study on Macular Degeneration
A major observational study from Ontario, Canada, examined health records from over one million adults with diabetes between 2020 and 2023.
The key finding: patients using GLP‑1 drugs like Ozempic or Wegovy were about twice as likely to develop neovascular (wet) age‑related macular degeneration (nAMD) compared to non-GLP‑1 users (0.2% vs. 0.1%).
While the absolute risk remains small, experts warn that long-term users—especially older patients with existing conditions—should have regular retinal screenings and report any vision changes immediately. The risk increases further in those on treatment for over 30 months.
2. Rare but Serious: NAION, or “Eye Stroke”
Another critical concern is non‑arteritic anterior ischemic optic neuropathy (NAION)—often described as an “eye stroke.” It results from reduced blood flow to the optic nerve and can cause sudden, often permanent vision loss. Reports from JAMA Ophthalmology have linked at least nine patients experiencing NAION or related conditions (like papillitis and retinal damage) after using semaglutide or tirzepatide.
Individual patient stories add to the alarm. For example, mechanic James Norris, aged 56, reported vision loss while on Mounjaro, later diagnosed as NAION. However, medical authorities stress that causality isn’t confirmed, and the overall rate of NAION remains low.
3. Regulatory Alerts from EMA and TGA
Health authorities are actively responding:
- The European Medicines Agency’s PRAC issued a warning that NAION is a “very rare” but documented adverse effect of semaglutide (in Ozempic, Wegovy, Rybelsus) and recommended updates to product information. Patients are urged to stop treatment and seek an ophthalmologist if sudden vision loss occurs.
- Australia’s Therapeutic Goods Administration (TGA) reported over 40 cases of optic nerve disorders (including some blindness) linked to Ozempic and Wegovy between 2020 and early 2025.
A Reuters report summarized recent data showing that Ozempic doubled the risk of NAION after two years, reinforcing similar findings reported in Europe.
4. What Experts Say: Balancing Risk and Benefit
Ophthalmologists and endocrinologists emphasize that while the relative risk doubles, the absolute risk remains small—for instance, rising from 0.1% to 0.2%. But they advise:
- Careful patient monitoring, especially among those with preexisting eye conditions, high blood pressure, or a history of strokes.
- Routine eye exams, including self-tests, to detect early signs.
- Prompt action: stop the medication at the first sign of sudden vision changes.
Novo Nordisk and Eli Lilly—the pharmaceutical companies behind Ozempic, Wegovy, and Mounjaro—maintain that benefits outweigh risks, but they also stress the importance of heightened awareness among doctors and patients.
5. How Patients Are Reacting
Real-world accounts show mixed responses:
A UK user on Facebook shared they experienced only smelly burps and tiredness after losing over 100 lb—but didn’t mention eye issues.
Others recount gastrointestinal discomfort, but vision changes are rare. Still, when they occur—like sudden blindness—they tend to attract considerable media coverage.
6. The Biological Unknown: What Might Be Happening?
Researchers are still trying to understand why GLP‑1 agonists might affect the eye:
They could potentially impact blood vessels in the retina or interfere with optic nerve blood flow, especially in patients with diabetes and hypertension.
Some metabolic changes or rapid glucose reductions might indirectly stress the eye, but the mechanisms are not yet fully understood.
A large-scale, ongoing five-year study in the US is exploring this issue further.
7. Final Thoughts and Recommendations
If you’re using Mounjaro or Ozempic—or thinking about starting—here are the key things to keep in mind:
- The risk of vision problems is low, but it can be serious. There’s no need to panic, but it’s important to stay informed.
- If you’re over 50 or have diabetes, make sure to have regular eye check-ups.
- If you experience sudden vision changes, such as blurriness or loss of vision, stop taking the medication and see a doctor immediately.
- Before starting treatment, talk to your healthcare provider about the potential risks and benefits, especially if you already have eye problems or high blood pressure.
- Health agencies are continuing to monitor these medications, and more data is still being collected to understand the risks better.
8. Where Science Goes From Here
Future priorities include:
- Confirming whether GLP‑1s directly cause these eye conditions or simply exacerbate preexisting risk.
- Identifying who is most susceptible—for example, age, coexisting diseases, and duration of use.
- Exploring alternative dosing schedules, dual therapies, or protective strategies to minimize risk.
- Continuing surveillance via regulatory and pharmacovigilance systems.
The current evidence shows a modest but real signal linking GLP‑1 weight-loss drugs like Ozempic and Mounjaro to rare but serious eye conditions—particularly in long-term users or those with other risk factors. The recommended approach: stay informed, get regular eye exams, act quickly on visual symptoms, and always weigh individual benefits against possible risks.
