GLP-1 receptor agonist exposure and non-arteritic anterior ischaemic optic neuropathy: an illustrative case.

CLINICAL RELEVANCE: Non-arteritic anterior ischaemic optic neuropathy may occur following exposure to glucagon-like peptide-1 receptor agonists, although a causal relationship has not been established. BACKGROUND: Recent evidence has raised concern regarding a possible association between glucagon-like peptide-1 receptor agonists and non-arteritic anterior ischaemic optic neuropathy. We describe an illustrative case occurring in a younger patient without diabetes mellitus or hypertension. METHODS: A 37-year-old woman with obesity and insulin resistance developed painless unilateral visual loss following three once-weekly doses of semaglutide, all administered before symptom onset. Clinical examination, multimodal ophthalmic imaging, visual field testing, neuroimaging, and laboratory investigations were performed. RESULTS: The right eye showed optic disc oedema, a dense inferior altitudinal visual field defect, and marked peripapillary retinal nerve fibre layer thickening, supporting a diagnosis of non-arteritic anterior ischaemic optic neuropathy. Investigations excluded alternative inflammatory, demyelinating, infectious, arteritic, compressive, and pseudopapilloedema-related causes. At three months, the optic disc oedema had resolved with residual pallor, while the visual field defect persisted. CONCLUSIONS: Although causality cannot be established from a single case, recent glucagon-like peptide-1 receptor agonist exposure may be relevant when evaluating atypical optic neuropathy in younger patients.