脳動脈瘤，視交叉部直接圧迫による同名半盲

Homonymous Hemianopsia due to Chiasmal Compression by Intracranial Aneurysm

Ⅰ．はじめに

　同名半盲はその特異な視野変化から脳内病変の局所診断に重要な位置を占めているが，脳動脈瘤により同名半盲を呈したという報告は数少ない^{1-10，12，13，15-22）}．最近，われわれは脳動脈瘤により同名半盲を呈した2症例を経験したので，文献的考察を加え報告する．

Eight cases of homonymous hemianopsia due to chiasmal compression by intracranial aneurysms have been reported in the literatures. Two similar cases were experienced in our clinic and reported. Of the total 10 cases, 8 were giant aneurysms—over 2 cm in diameter— and 9 cases were aneurysm developing medially from the internal carotid artery. Visual disturbances in all the 10 cases were incongruous homonymous hemianopsia without macula sparing. It should be noted that the existence of aneurysm is possible, in patients with homonymous hemianopsia, even when there is no other clinical evidence of mass lesion.