Intermittent Diplopia can be a Sentinel Sign of Impending Rupture of a Cerebral Aneurysm Compressing the Third Cranial Nerve

Intermittent diplopia with a normal neuro-ophthalmic examination is not generally considered adequate justification for a brain imaging study because the cause is most often a decompensated phoria. We present a patient who reported intermittent diplopia that evolved into a third nerve palsy and, within two days, rupture of a posterior communicating artery aneurysm.