Sudden loss of vision in a patient with significant ipsilateral internal carotid disease.

A 74-year-old man developed sudden onset of painless persistent partial loss of vision in the right eye 3 days after right total knee replacement. The initial investigation was for amaurosis fugax with a normal CT scan of the brain but the carotid Doppler confirmed >90% stenosis of the right internal carotid artery. Urgent ophthalmological review confirmed anterior ischaemic optic neuropathy. Subsequently, he lost his vision completely in the right eye. He had a previous high risk hemispheric transient ischaemic attack with carotid Doppler reported as normal.