等亮度正弦光栅颜色视诱发电位的色觉机理研究及相关软件应用基础研究

Color vision is one of the important visual functions of human. The early detection of acquired color vision deficiency is very necessary，otherwise，the disease will go on rapidly, which may lead to severe vision loss. The chromatic VEP, which assesses the integrity of the neural pathways responsible for colour vision, is a useful electrophysiological indicator of early colour vision changes.The Chromatic VEP provides a new direction for color vision detection According to the different characteristic of the three pathways, we make a model for equilumant chormatic VEP stumilus. Stimuli were equiluminant horizontal sinusoidal gratings. Chromatic modulation was performed along the L-M (red-green) and S-(L + M) (blue-yellow) cardinal axes of color vision（ie P and K pathway）, in order to selectively influence the activity of the corresponding opponent mechanism or L-, M- and S cone classes. High temporal frequency chromatic VEP stimulation was used to detect congenital red-green color deficiency through L+M pathway and "Equiluminance turning curve" were established according to measurements at the each luminance conditions. We use low temporal frequency stimulation for acquired color vision deficiency through chromatic pathway. At the same time, combine these results of FD-OCT, perimetry and Chromatic VEP test provides a better understanding of the pathophysiology of visual involvement in acquired color vision deficiency. The method overcomes the limits of all the traditional subjective methods used in clinical practice, fulfills the impersonal and quantitative requirements in color vision deficiencies test. Except that it distinguishes the dichromats and the anomalous trichromats efficiently, it also makes a foundation for the future research of color vision deficiencies.

获得性色觉障碍患者如得不到早期诊断和治疗，往往导致严重而永久的视功能障碍。近来研究发现颜色VEP可以更好的提示视觉通路损伤，可早期诊断疾病，为视路疾病检测提供了新的方向。本研究拟突破以往棋盘格刺激模式局限，设计新型等亮度正弦光栅颜色VEP刺激模式,并针对M、P、K三条通路各自的特性，分别建立光学模型并计算该刺激模型对三种椎体细胞的刺激度，进而确保颜色VEP针对性刺激单条视觉通路，深化色觉视功能检测，建立客观准确的色觉检测系统。首次联合颜色VEP检测和FD-OCT形态学检测、视野检测等，更好的掌握疾病病理生理变化，深入了解疾病发展机制。本研究突破临床心理物理学色觉检测方法，可针对单条视路功能进行检测评估，实现对色觉障碍人群客观定量的检测分类以及疾病的早期诊断，达到对眼色觉功能全面客观评价的目标，具有较高的科学价值和临床意义。

本研究创新性的设计等亮度正弦光栅颜色VEP刺激模型，依据不同颜色的椎体细胞刺激值，分别针对M, P, K, 三条通道各自特性进行单通道的检测。项目选取先天性色觉异常及正常志愿者，完成实验数据的收集，建立光学模型和等亮度点模型，计算相应椎体细胞刺激值。并对青光眼患者，中浆患者及黄斑变性患者，进行等亮度颜色VEP给撤刺激检测，以及FD-OCT、视野等相关检测。.研究结果显示：1.色觉正常者在红色亮度比T＝R/(R+G)=0.5时，VEP波幅最低，波动范围为0.5~0.52，即等亮度点为0.5~0.52。而色觉障碍者等亮度点相对于正常值均有所偏移。偏移方向与理论推测方向相符。2.中浆患者组的颜色光栅刺激及亮度对照光栅刺激均较正常对照组出现VEP潜时的延长，而在颜色刺激VEP中，以S-轴向VEP潜时延长的最为明显。回归分析显示，视网膜内界膜值外界膜间的距离与S-轴向VEP潜时有显著相关性。表明了S锥体细胞和通道更易受损，k通道传导细胞丢失，导致了外核层和外丛状层厚度的下降。3.青光眼患者组同样颜色光栅刺激及亮度对照光栅刺激均较正常对照组出现VEP潜时的延长，以S-轴向VEP潜时延长的最为明显，使用回归分析发现，且S-轴向VEP潜时与视野的平均缺损值有显著相关性。由于S-轴向上的小条纹神经节细胞仅占5%，故S-轴向通路上的神经纤维非常稀疏没有重叠，所以更易受到损害。4. 干性黄斑变性患者组同样颜色光栅刺激及亮度对照光栅刺激均较正常对照组出现VEP潜时的延长，以S-轴向VEP潜时延长的最为明显，使用回归分析，未发现各通路颜色VEP刺激与神经上皮厚度、玻璃膜疣等存在显著相关。.本项目为人们认识大脑颜色处理的不同通道，相关疾病的早期诊断，以及新型的颜色VEP仪器的研制，提供理论和实验基础，为视路疾病的检测提供了新的方向。