Sudden onset homonymous quadrantanopia

While looking at the starry night sky, a man in his 60s—a retired general practitioner with an unremarkable medical history—noticed sudden loss of vision in both eyes affecting the upper left quadrant of his visual field, accompanied by a mild headache. He did not experience any nausea or emesis. Review by an ophthalmologist the next morning showed homonymous upper left quadrantanopia and he was referred to neurologists. The original homonymous quadrantanopia persisted with no other neurological deficits and no laboratory abnormalities. Brain magnetic resonance imaging (fig 1) was performed 13 hours after the initial symptoms. Routine MR imaging techniques were used and showed a small area of abnormal restricted diffusion in the primary visual cortex of the right occipital lobe (fig 1 left panel, arrow), and hyperintensity and full demarcation of the lesion (fig 1 right panel, arrow). There were no …