A 29-year-old woman presents with 10 days of progressive daily headache and brief episodes of greying vision. She is six weeks postpartum and takes a combined oral contraceptive. Examination shows bilateral optic disc swelling and a left sixth-nerve palsy; there is no fever or focal limb weakness. Which one of the following is the most appropriate investigation before considering lumbar puncture?
Shared by ChoiceHubmiddle twist