Semaglutide has rapidly become one of the most prescribed medications in modern medicine, but its ophthalmic risk profile remains incompletely characterized. A case report published in Survey of Ophthalmology raises a clinically important signal: GLP-1 receptor agonist therapy may be implicated in non-arteritic anterior ischemic optic neuropathy (NAION), a form of vision loss that can cause permanent damage to the optic nerve.
The case involves a 38-year-old man with poorly controlled type 2 diabetes and hypertension who was actively receiving semaglutide when he experienced sudden, painless vision loss in his left eye. Ophthalmic evaluation found acute optic disc edema in that eye alongside optic disc pallor in the right eye — a combination mimicking Foster Kennedy syndrome, which classically suggests an intracranial mass. After neuroimaging excluded a space-occupying lesion, the clinical picture was reinterpreted as pseudo-Foster Kennedy syndrome: an unrecognized prior NAION in the right eye and a new acute NAION event in the left. The patient also exhibited severe nonproliferative diabetic retinopathy and cystoid macular edema bilaterally, compounding the visual threat.
This case adds to a growing body of concern following a 2024 JAMA Ophthalmology study that identified a statistically elevated NAION risk among semaglutide users with type 2 diabetes and obesity compared to alternative agents. The mechanism remains speculative but may involve rapid reductions in blood pressure, altered optic nerve head perfusion, or the crowded disc anatomy common in diabetics. Critically, confounders are substantial: poorly controlled diabetes and hypertension are themselves independent NAION risk factors, making causality impossible to establish from a single case. Clinicians prescribing semaglutide — particularly to patients with vascular comorbidities or small cup-to-disc ratios — may benefit from baseline ophthalmic evaluation. For the broader semaglutide-using population, this remains a low-frequency but sight-threatening signal warranting continued pharmacovigilance.