A 57-year-old previously fit and well female attended Moorfields eye hospital with a two week history of reduced vision and a slowly enlarging grey area in her central visual field that had started after a flight to France from the UK. Best corrected visual acuity (VA) on presentation was 6/6 in her right eye and 6/9 in the affected left eye. On examination she had a left swollen disc with multiple cotton wool spots and arterial sheathing. Visual field confirmed a central scotoma with some inferior field defect. Examination of the right eye was unremarkable. Provisional diagnoses at this time were of a non-infectious vasculopathy or platelet emboli. She underwent a full inflammatory and thrombotic screen. Full blood count, erythocyte sedimentation rate, treponemal screen, anti-nuclear antibody, borrelia antibody, rheumatoid factor, double-stranded DNA, neutrophil cytoplasmic antibody and complement screen were all within the normal range. Magnetic resonance imaging of the brain showed mild supratentorial small vessel ischaemic disease with scattered lesions in deep and subcortical white matter, and small mature right cerebellar infarcts. ECG was normal and carotid doppler scans unremarkable. Transthoracic echocardiogram and bubble studies however demonstrated a patent foramen ovale and a right-to-left shunt on microbubble injection. She was subsequently commenced on warfarin. Follow-up showed a slow clearing of the platelet emboli from the arterial system, though VA remained the same.