高度近视眼的黄斑局部视网膜电图频谱分析

Fourier analysis of macular local electroretinogram in high myopia

目的 :应用局部视网膜电图 (localelectroretingoram ,LERG)频谱分析方法 ,进一步了解高度近视眼黄斑部光感受器细胞与光感受器后神经元细胞功能异常的情况。方法 :6 6例高度近视眼患者 (12 8眼 )的LERG被记录研究。应用手提眼底镜式局部刺激器 ,通过放大的瞳孔直视眼底监控固视状况 ,闪烁光频率 31Hz。结果 :与对照组相比 ,高度近视眼底仅有豹纹状眼底改变和伴后巩膜葡萄肿两组闪烁LERG的 1f与 2f均有降低(P <0 .0 5 ) ,2f在后组中下降显著 (P <0 .0 1) ,且 1f/2f比值有明显增加。对屈光度分组的Fourier分析发现 :1f与 2f在各组均有降低 (P <0 .0 5 ) ,2f的下降在 - 10D以上组显著 (P <0 .0 1) ;1f/2f比值在早期RP病变表现正常或轻度异常 ,随发病病程增加有升高趋势。结论 :高度近视眼的黄斑功能早期以视网膜外层为主 ,随着病情的发展 ,黄斑部内层的受累有加重趋势。不同眼底改变与黄斑功能受损程度具有一致性。LERG频谱分析对高度近视眼黄斑功能的定位定性诊断具有临床意义。

Objective:To investigate the physiological characteristics and sites of macular dysfunction in eyes with high myopia by evaluating fundamental harmonic(1f) and second harmonic(2f) components of flicker focal electroretinogram(FERG).Methods:FERG were recorded in 128 eyes with high myopia(refractive errors ranged from -6 to -12D) to a flickered sinusoidally to 31Hz with a hand held stimulator with direct visualization of the fundus through dilated pupils. The eyes with high myopia were divided into two groups: 66 eyes showing only tigrolving fundus(group Ⅰ) and 62 eyes associated with posterior staphyloma involving the macula(group Ⅱ).Results:Compared to controls, the eyes with high myopia showed loss of both fundamental and second harmonic amplitudes. The ratios of fundamental second harmonic amplitudes in group Ⅰ were nearly normal and slightly abnormal in group Ⅱ. The peak latency in group Ⅱ was significantly longer than that in group Ⅰ. On average, the second harmonic amplitudes decreased more obviously than fundamental harmonic amplitudes and 2f/1f significantly decreased as refractive errors increased.Conclusion:The results suggest that in the eyes with high myopia, both receptoral and postreceptoral sites contribute to macular dysfunction. The level of macular cone dysfunction in the eyes with or without posterior staphyloma is different. It would be of clinical value to obtain a fundamental second harmonic ratio in order to assess the disturbance in the different site of macular.