前部虚血性視神経症に対する視神経鞘減圧術の治療成績

Results of optic nerve sheath decompression for anterior ischemic optic neuropathy

　進行性の左視力低下を示した前部虚血性視神経症の62歳男性例に対し，発症後51病日に経眼窩的アプローチによる左視神経鞘減圧術を施行した。左視力は術前0.05が術後0.07とほぼ不変であったが，原因不明の視神経萎縮を呈していた右視力は術前0.6から術後0.9と改善が見られ以後両眼とも安定した視力が得られた。視性誘発電位は術前と術後で変化がなく，術後左視野に軽度の狭窄が生じた。術後合併症として後毛様神経の障害による一過性の左内眼筋麻痺が認められた。

A 62-year-old male presented with blurred vision in the left eye. He was diagnosed as left anterior ischemic optic neuropathy based on optic disc pallor, inferior hemianopia and filling defect in the optic nervehead by fluorescein angiography. The visual acuity in the affected eye deteriorated further from the initial value of 0.2 despite systemic corticosteroid. Optic nerve sheath decompression was performed on the left side 52 days after onset. The left visual acuity remained at 0.07, almost the same as before surgery. His right eye, which had a history of optic atrophy, showed improvement in visual acuity from 0.6 to 0.9 after surgery. Visual field and visual evoked potential (VEP) remained unchanged in the right eye. The left visual field showed mild constriction. Incomplete internal ophthalmoplegia in the operated eye remained as complication of surgery, probably due to involvement of posterior ciliary nerve.