We present a case of right sided blindness caused by a cavernous carotid artery aneurysm in a 17-year-old patient presenting with an Alagille syndrome. The diagnosis was made by magnetic resonance imaging and confirmed by angiography. This aneurysm was treated successfully with endovascular placement of detachable balloons. Cerebral vascular malformations are rarely reported in association with this syndrome. We discuss the clinical presentation, diagnosis, treatment and detection of this type of abnormality.