各象限で異なった多局所視覚誘発電位を示した視神経炎の1例

A case of optic neuritis with variable responses of multifocal visual evoked potential in different quandrants

要約　目的：象限により異なった多局所視覚誘発電位（mfVEP）を示した症例の報告。症例と方法：左眼の眼球運動痛と視力低下で60歳男性が受診した。矯正視力は右1.2，左0.5であり，3日後に左眼視力が0.05に低下した。副腎皮質ステロイドの全身投与などで7か月後に左眼視力は1.5に回復した。急性期と回復期にmfVEPを測定し，象限毎の違いを検索した。各象限のmfVEPの正常値として，正常者20例20眼での値を採用した。結果：急性期の自動視野計による視野測定で，感度低下が軽度な象限でも，mfVEPでは明らかな反応低下があった。回復期で視野低下が回復した象限でも，mfVEPで潜伏時が延長していた。急性期に感度低下が軽度であった象限では，mfVEP反応が回復していた。結論：mfVEPを使うことで，視神経炎に対する治療効果の判定と，周辺部視野での新規な視機能評価が可能である。

Abstract.　Purpose：To report a case of optic neuritis with variable responses of multifocal visual evoked potential（mfVEP）in different quandrants. Case and Method：A 60-year-old male presented with pain and impaired visual acuity in his left eye. His corrected visual acuity was 1.2 right and 0.5 left. It decreased to 0.05 left 3 days later. He recovered 7 months later with visual acuity of 1.5 after systemic corticosteroid. The left eye was tested by mfVEP during the course of the disease. Due attention was paid to differences in mfVEP response in different quandrants. Findings in 20 eyes of 20 healthy volunteers served as baseline value for mfVEP. Results：During the acute phase, mfVEP was reduced in quadrants that showed only slight reduction by automated perimetry. During the phase of recovery, mfVEP showed prolonged latency time in quadrants that showed normal responses by automated perimetry. After recovery, mfVEP had sufficiently recovered in quadrants that showed slight decrease in sensitivity during the acute phase. Conclusion：Multifocal visual evoked potential（mfVEP）promises to be useful in evaluating the therapeutic effect on optic neuritis and in testing the visual function in the periphery.