Health
FDA warns of rare eye‑loss risk with GLP‑1 diabetes and weight‑loss drugs
By Ravi Hari
The U.S. Food and Drug Administration has cautioned that glucagon‑like peptide‑1 receptor agonist (GLP‑1 RA) medications, used for type 2 diabetes and obesity, may increase the risk of a rare eye condition that can cause sudden, permanent vision loss. The condition, non‑arteritic anterior ischemic optic neuropathy (NAION), can cause painless loss of vision in one eye and may first be noticed upon waking. Symptoms include blurred vision, blind spots, tunnel vision, colour distortion and reduced central sharpness. The FDA urged patients on GLP‑1 RAs to watch for these signs and to contact a health professional immediately if they occur. Following a comprehensive safety review, the agency now requires all GLP‑1 RA manufacturers to add a warning about the potential NAION risk in the ‘Warnings and Precautions’ section of their product labels.
GLP‑1 drugs mimic a natural hormone that regulates blood sugar after meals and influences appetite. They are widely prescribed for type 2 diabetes, weight loss, and to reduce cardiovascular events, kidney disease progression, obstructive sleep apnoea, and metabolic dysfunction‑associated steatohepatitis.
In an analysis of 126 randomised controlled trials involving 134,253 participants, the FDA found 15 probable NAION cases: 10 among GLP‑1 RA users and five among placebo recipients. No cases occurred in participants taking other non‑GLP‑1 glucose‑lowering drugs. The incidence rate was 6.4 cases per 100,000 person‑years for GLP‑1 RA users versus 3.8 for the comparator group. The general population incidence for adults over 50 is 2.3–10.2 per 100,000 per year.
A retrospective study using the FDA’s Sentinel Real‑World Evidence Data Enterprise examined adults with type 2 diabetes who started GLP‑1 RAs or other common diabetes medications between 2019 and 2024. NAION rates were 30–32 per 100,000 person‑years for GLP‑1 RA users, 31 for SGLT‑2 inhibitor users, and 26 for DPP‑4 inhibitor users. The study did not find a statistically significant difference between GLP‑1 RAs and SGLT‑2 inhibitors, but did find a higher risk compared with DPP‑4 inhibitors.
The FDA noted that NAION has been reported with all marketed GLP‑1 RA products. Individuals who have had NAION once are at higher risk of recurrence and of developing the condition in the other eye. Other risk factors include smoking, diabetes, high blood pressure, sleep apnoea, anaemia and kidney disease.
Healthcare professionals are advised to inform patients of this potential risk and to instruct them to report sudden, painless vision loss or visual field defects immediately. Doctors should refer suspected cases to an ophthalmologist promptly and consider discontinuing GLP‑1 RA therapy if NAION develops, unless the benefits clearly outweigh the risks.
Frequently asked questions
What is NAION and how does it affect vision?
NAION is a rare eye condition that can cause sudden, painless loss of vision in one eye, often first noticed upon waking, with symptoms like blurred vision, blind spots, tunnel vision, colour distortion, and reduced central sharpness.
What is the risk of NAION with GLP‑1 RA drugs compared to other diabetes medications?
In a retrospective study, NAION rates were 30–32 per 100,000 person‑years for GLP‑1 RA users, 31 for SGLT‑2 inhibitor users, and 26 for DPP‑4 inhibitor users; no significant difference between GLP‑1 RAs and SGLT‑2 inhibitors, but higher risk compared with DPP‑4 inhibitors.
What should patients and doctors do if NAION is suspected?
Patients should report sudden, painless vision loss or visual field defects immediately; doctors should refer suspected cases to an ophthalmologist promptly and consider discontinuing GLP‑1 RA therapy if NAION develops, unless benefits outweigh risks.