Evidence-graded answer
Can GLP-1 cause vision problems?
A small observational study (JAMA Ophthalmology 2024) flagged a possible association between semaglutide and NAION (non-arteritic anterior ischemic optic neuropathy) — a rare cause of sudden vision loss. Subsequent analyses have been mixed. Any sudden vision change while on GLP-1 warrants urgent ophthalmology referral.
NAION baseline rate in adults with type 2 diabetes is roughly 1-5 per 100,000 per year. The JAMA Ophthalmology 2024 case-control study reported elevated odds among semaglutide users; the absolute risk increase remains low.
Sustained-VISION (semaglutide trial in retinopathy) showed early worsening of diabetic retinopathy in patients with rapid A1c reduction — a known phenomenon, not unique to GLP-1.
Practical guidance: schedule a baseline ophthalmology exam if you have diabetes, and seek same-day care for any sudden vision loss, gray spot, or new visual-field defect.
Source: JAMA Ophthalmology 2024, JAMA Ophthalmology