Title: Diabetic Retinopathy Masking NAION in a Patient on Semaglutide: A Case of Diagnostic Challenge

Authors: Roque De Monte Furtado¹, Yathavi Charavanamuttu¹, Miss Vivi Riga²

Affiliations: ¹GKT School of Medical Education, King's College London, London, UK; ²Department of Ophthalmology, Guy's and St Thomas' Hospital NHS Foundation Trust, London, UK

 

Background

• Non-arteritic anterior ischaemic optic neuropathy (NAION) is characterised by acute painless visual loss, relative afferent pupillary defect, impaired colour vision, ischaemic sectoral optic disc oedema and visual field defects.

• It is thought to be a result of acute ischaemia of the optic nerve head, though the exact pathogenesis remains unclear.

• Reports suggest an association between NAION and glucagon-like peptide-1 receptor agonists (GLP-1 RAs).

• Here we present a case of NAION in a diabetic patient on semaglutide that was initially misdiagnosed as non-ischaemic central retinal vein occlusion (CRVO).

   

Case Details

• Patient: 50-year-old male of Bangladeshi heritage with acute onset of reduced central vision in his left eye.

• Medical History: Asthma, HTN, T2DM. Routine bloods unremarkable.

• Clinical Features (Left Eye):

  • Visual Acuity: 3/60 (Acute Drop)

  • Colour Vision (Ishihara): 3/14 (Dyschromatopsia)

  • IOP: 22mmHg

  • Pupils: Positive RAPD

  • Fundoscopy: Sectoral Disc Oedema, Haemorrhages, Macular Oedema

• Initial Working Dx: Non-ischaemic CRVO (LE).

• Follow-up: Vision improved to 6/7.5; Imaging showed resolving macular oedema and RNFL swelling.

• Key History Uncovered: Patient had started Semaglutide shortly before onset.

• Revised Dx: NAION based on superior ganglion cell layer loss (LE: 0.31 µm; RE: 0.42 µm).

   

Discussion

• The Diagnostic Mimic: Concurrent NPDR/Maculopathy and semaglutide-induced NAION created overlapping findings.

• The Initial Pitfall: Presentation mimicked CRVO, but the presence of a pronounced RAPD and lack of venous tortuosity were key red flags for an optic nerve aetiology.

• The Semaglutide Signal: Literature suggests a 4x to 7x increased risk of NAION in diabetics prescribed semaglutide.

• Final Confirmation: 2-year follow-up imaging revealed sectoral superior GCL loss and optic pallor, pathognomonic for NAION.

   

Take Home Points

• High Index of Suspicion: In diabetics with sudden vision loss, a positive RAPD should prompt a neuro-ophthalmic workup regardless of retinopathy.

• The "Semaglutide History": Screening for recent GLP-1 RA initiation is essential in acute optic neuropathy workups.

• Multimodal Imaging Utility: Early OCT and visual fields help differentiate ischaemic atrophy from diabetic macular changes.

• Interdisciplinary Care: Ensure communication between Ophthalmology and the Diabetes team to manage glycaemic targets safely.

   

References

1. Hathaway JT, et al. JAMA Ophthalmol. 2024 Aug 1;142(8):752-759.

2. Amini A, et al. Acta Ophthalmol. 2025 Sep;103(6):615-621.

3. Natividade GR, et al. JAMA Ophthalmol. 2025 Sep 1;143(9):759-768.