Visual field defects typically caused by lesions in the optic nerve or optic chiasm may be caused indirectly by subdural haematomas. A 61-year-old man survived transtentorial herniation caused by subdural haematomas that resulted from shaking his head in an attempt to remove a cockroach impacted in his external auditory canal. Bilateral incomplete posterior cerebral artery infarction of both inferior tips of the occipital lobe resulted in bilateral superior quadrantanopia. There are no previous reports of tentorial herniation causing this permanent outcome.