視神経炎（症）におけるカラーパターンVECPによる色覚異常の他覚的検討

Color pattern VECPs in optic neuritis

　視神経炎（症）3例を対象に混同色を使用したカラーパターン視覚誘発電位（カラーPVECP）で他覚的に色覚を検討した。カラーPVECPはProtan，Deutan，Tritanのそれぞれのほぼ混同色を2種ずつ使用し，それらを1秒間に3回反転する市松模様を呈示しそれぞれProtan刺激Deutan　刺激，Tritan刺激と称した。P100成分の頂点潜時，振幅を測定した。自覚検査はFarnsworth-Munsell 100-hue test，panel D-15，Lanthonyのdesaturated panel D-15，標準色覚検査表第2部後天異常用（SPP　Ⅱ）で施行した。自覚的に赤緑異常を示した例では，カラーPVECPの青黄系より赤緑系の混同色の反応が悪く自覚的に青黄異常を示した例では，カラーPVECPの赤緑系より青黄系の混同色の反応が悪かった。先天性赤緑異常を合併した例では後天性赤緑異常をカラーPVECPによって先天異常と判別できた。カラーPVECPによって視神経炎（症）の色覚異常を赤緑異常，青黄異常別に判別できる可能性が示された。

We recorded the visually evoked cortical potentials (VECPs) in 3 cases with optic neuritis and acquired color vision defects. We used a color pattern gener-ator displayed on a color visual display terminal developed by Adachi-Usami. We employed 4 kinds of stimuli as displayed on the TV monitor: a black -and-white chackerboard and two opponent color checks along the confusion lines for protan, deutan and tritan. They were named respectively, as black -and white, protan, deutan and tritan stimulus.

The latency and amplitude of p 100 component were measured. Normal subjects showed a latency of less than 120 msec for either of the four stimulus conditions. A case with subjective red-green defectsmanifested more attenuated response to protan and deutan stimuli than tritan stimulus. Another case with subjective blue-yellow defects showed a reduced response to tritan stimulus than protan or deutan one. A third case with acquired red-green defects in the right eye associated with deuter-anomaly in both eyes showed more disturbed response to protan and deutan stimuli in the right than in the left eye.

Use of color pattern VECPs thus enabled detec-tion of acquired red-green and blue-yellow defects. It was also helpful in differentiating acquired red -green defects from congenital ones.