optic nerve compression either by pressing the nerve against the vessel or the neighboring dura or bone. The spectrum of clinical signs and symptoms of optic nerve compression in this area is rather wide and includes acute as well as slowly progressive visual loss and all kinds of visual field defects in the presence of a normal disk, papilledema, pri­ mary optic atrophy or cavernous optic atrophy mimicking var­ ious clinical disease entities such as retrobulbar optic neuritis, anterior and posterior ischemic optic neuropathy, soft glaucoma and others. Some of the lesions causing optic nerve compression in this area are rather small and need to be visualized or excluded by thin section CT such as pneumosinus dilatans of the sphenoid bone, dolichoectasia of the internal carotid artery, small men­ ingiomas around the optic foramen and others.