A 19-year-old woman, who was 16 weeks post partum, collapsed with loss of consciousness. Following awakening she suffered abrupt loss of vision. Partial recovery occurred, although she has been left with bilateral homonymous hemianopia with sparing of vision just to the left of the vertical meridian. Magnetic resonance imaging demonstrated bilateral occipital infarcts, sparing the lips of the calcarine sulcus on the right. This is compatible with our expectation that the vertical meridian of the retinotopic map is represented at the superior and inferior lips of the calcarine sulcus.