GLP-1 Drugs Tied to Small Rise in Rare Vision-Loss Condition, Rutgers Study Finds

A study published this week in the Annals of Internal Medicine links widely prescribed GLP-1 receptor agonist medications, including Ozempic, Wegovy, Mounjaro, and Zepbound, to a modest increase in the risk of ischemic optic neuropathy, a rare condition that can cause sudden and potentially permanent vision loss.

The condition, known as ION, occurs when blood flow to the optic nerve is reduced. Because the optic nerve carries visual signals from the eye to the brain, damage to it can produce rapid partial or complete loss of sight in the affected eye.

Researchers at Rutgers University used U.S. insurance claims data on adults aged 18 to 65 with Type 2 diabetes, covering the years 2017 through 2022, according to a summary released by the university. They compared new users of GLP-1 drugs against new users of two other diabetes drug classes: SGLT2 inhibitors and DPP4 inhibitors. The study included more than 161,000 GLP-1 users, more than 122,000 SGLT2 inhibitor users, and more than 86,000 DPP4 inhibitor users, as reported by Inside Precision Medicine.

The 18-month ION rate was 8.5 per 10,000 among GLP-1 users versus 5.5 per 10,000 among SGLT2 inhibitor users, a risk difference of 3.0 additional cases per 10,000 patients, according to figures published in the Annals of Internal Medicine. Against DPP4 inhibitor users, the gap was 3.6 additional cases per 10,000 over the same period.

The absolute numbers are small. But who showed up in those 81 ION events matters clinically: 85 percent were older than 50, and about 70 percent were men, according to data in the Annals paper. That's a skew that prescribers should have in mind when counseling patients in that demographic.

"Although ischemic optic neuropathy was rare, it is clinically important because it can involve sudden vision loss," said Chintan Dave, a core faculty member at Rutgers' Center for Pharmacoepidemiology and Treatment Science, in a statement reviewed by ScienceDaily. Dave added that the risk increase was small but that clinicians and patients should be aware of the potential association.

The researchers are careful about what the data can and cannot say. The study used claims records, not clinical charts, and lacked diagnostic codes specific to the most common ION subtype, NAION. Missing data on body mass index and diabetes duration are also noted as limitations in the Annals of Internal Medicine paper. The authors flag residual confounding as a real concern, meaning sicker patients may have been more likely to receive a GLP-1 drug in the first place, and sicker patients may also carry a higher baseline optic nerve risk.

That caveat matters. When the researchers looked only at patients on metformin monotherapy, a marker for less severe disease, the risk difference shrank. That suggests some of what the study detected could reflect the underlying health of the patients rather than the drugs themselves.

The Rutgers findings don't stand alone. The UK's Medicines and Healthcare products Regulatory Agency issued a Drug Safety Update in February 2026 advising that semaglutide, the active ingredient in Ozempic and Wegovy, had been very rarely reported in association with the same eye condition. The MHRA called for urgent ophthalmological referral for any patient on semaglutide who reports sudden vision loss, according to that agency document.

A separate nationwide cohort study from Sweden, also published in the Annals of Internal Medicine, found a roughly 1.9-fold higher relative risk of the condition in GLP-1 users compared with SGLT2 inhibitor users, though absolute risks remained below 0.1 percent at one year, according to the journal's published abstract.

For patients currently taking these medications, the practical guidance is straightforward: sudden or painless blurring or dimming in one eye is worth an urgent call to a clinician, not a wait-and-see. That's true whether you're on a GLP-1 drug or not, but given how many millions of people now take these medications, it's a symptom pattern that primary care physicians and pharmacists need to be naming out loud at the point of prescribing.

Sources cited:
- Annals of Internal Medicine (Rutgers target trial emulation) (https://doi.org/10.7326/ANNALS-25-00860)
- ScienceDaily / Rutgers University press release (https://www.sciencedaily.com/releases/2026/10/261014015521.htm)
- Inside Precision Medicine (https://www.insideprecisionmedicine.com/topics/translational-research/glp-1-treated-patients-with-diabetes-have-raised-risk-for-eye-condition/)
- Annals of Internal Medicine (Swedish nationwide cohort) (https://doi.org/10.7326/annals-25-02096)
- UK MHRA Drug Safety Update, February 2026 (https://assets.publishing.service.gov.uk/media/69847cb7468d351e1406b4d2/DSU_-_Semaglutide_and_NAION_-_5_Feb_2026.pdf)