エタンブトール視神経症の耳側感度低下

Depression of sensitivity in temporal visual field in ethambutol-induced optic neuropathy

要約　目的：エタンブトール視神経症の病型による視野障害の特徴がHumphrey視野で明確になるか検討した報告。対象と方法：エタンブトール視神経症連続5症例の視力および視野の経過を1年以上追跡した。結果：中心暗点型4例のGoldmann視野では，中心，傍中心暗点を認め，Humphrey視野では両眼の耳側感度低下を認めた。回復期でもHumphrey視野の耳側と鼻側の感度差は明らかであった。結論：中心暗点型エタンブトール視神経症のHumphrey視野は，過去の動物実験における視交叉の変性所見とよく符合した。エタンブトール視神経症では，視交叉が一次的に障害されやすい部位と考えられ，その検出にはHumphrey視野が適している。

Abstract.　Purpose：To report changes in visual field in patients of ethambutol-induced optic neuropathy. Cases and Method：This retrospective study was made on 5 patients who were receiving peroral ethambutol and who were diagnosed with optic neuropathy. All were females aged from 62 to 76 years, average 72 years. After discontinuation of ethambutol, they were followed up for one year or longer. Results：Four patients with central-or pericental type visual field defect by Goldmann perimetry showed depression of sensitivity in temporal field by Humphrey perimetry. Difference in sensitivity between temporal and nasal area was apparent during follow-up. Conclusion：The observed depression in sensitivity in temporal visual field simulated findings in optic chiasmal degeneration in animal experiments in literature. Optic chiasm appears to be sensitive to ethambutol-induced optic neuropathy. Humphrey perimeter promises to be useful for this disease entity.