斜视性弱视眼的多焦视诱发电位特征

Characteristics of multifocal visual evoked potentials in esotropic amblyopes

目的 研究斜视性弱视眼视野各部位视功能的变化。方法 记录和分析了 5例斜视性弱视眼和 45例正常对照眼的多焦 VEP。刺激图形由 6 1个六边形单元组成 ,每个刺激单元内有黑白格子 ,刺激野直径约 13.6°。在 VERIS系统电脑程序 (伪随机双极 m序列 )控制下 ,各刺激单元同时并互相独立地进行黑白翻转刺激 ,通过用快速 Walsh变换计算刺激与反应的互相关函数 ,分离提取到各自的反应波形。结果 斜视性 (内斜 )弱视眼在中央视野和颞侧视野 ,多焦 VEP潜伏期延长、振幅下降。按不同离心度的环分组统计 ,斜视性弱视眼与正常对照眼比较 ,P1 波潜伏期平均值在中央凹和第一环分别延长 2 0 .2 m s和11.2 m s;P1 - N2 振幅平均值在中央凹下降 6 8.8% ,在第一环下降 5 2 .6 % ,在第二环下降47.5 % ,N1 - P1 振幅平均值在中央凹下降 5 4.4% .按鼻颞侧分组统计 ,斜视性弱视眼与正常对照眼比较 ,潜伏期平均值在颞侧视野延长 10 .6 m s;P1 - N2 振幅平均值在颞侧下降6 6 .5 % ,N1 - P1 振幅平均值在颞侧下降 6 3.7% .斜视性弱视眼潜伏期平均值在颞侧视野比在鼻侧视野延长 11.2 ms;P1 - N2 振幅平均值在颞侧视野比在鼻侧视野下降 6 4.2 % ,N1 - P1振幅平均值在颞侧视野比在鼻侧视野下降 6 4.2 % .结论 本研究证实 。

Objective To investigate the variation of visual function across the visual field in esotropic amblyopes. Methods Data from five esotropic amblyopic eyes and 45 control eyes were analyzed. A VERIS system was used to generate a stimulus matrix containing 61 hexagons on a computer monitor. Each hexagon of the display contained a number of small black and white hexagonal patches, which reversed in polarity during stimulation according to a pseudo random binary m sequence. The VERIS system extracted the local responses by cross correlating the input and output signals. The latencies and amplitudes of the responses from the central 8.6 deg of arc in the visual field were analyzed. Results In esotropic amblyopia, the multifocal VEP latency was prolonged and the amplitude was reduced in the central region of the visual field. The mean amplitude was significantly smaller and the mean latency was significantly longer in the temporal visual field than that in the nasal visual field. Conclusion Results confirm that a greater foveal deficit of visual function and a greater visual loss in the temporal field than in the nasal field in esotropic amblyopia.