应用PRVEP P_(100)空间频率阈值客观评定视力的价值分析

目的研究图形翻转视觉诱发电位(PRVEP)P100波空间频率阈值在不同眼损伤情况下预估视力的价值,以期指导相关法医临床学鉴定。方法选取诊断明确、主观视力准确,另眼矫正视力基本正常(≥4.9)的法医学鉴定案例74例,共148眼别。分为4组:屈光间质混浊组(23眼别)、视网膜病变组(31眼别)、视神经病变组(20眼别)、健眼正常对照组(74眼别)。对上述案例进行图形翻转视觉诱发电位检查,记录P100空间频率阈值,并对空间频率阈值与视力的对数值,两者进行线性相关分析。结果184眼PRVEP空间频率阈值与视力的对数值之间呈显著的正相关(r=0.84,P<0.01),说明PRVEP P100空间频率阈值是客观评定视力的良好指标。但不同部位病变或损伤对PRVEP检测结果的影响不同,视神经病变组PRVEP空间频率阈值与主观视力两者间无统计学相关性(r=0.4,P>0.05)。结论PRVEP P100空间频率阈值是客观评定视力水平的良好手段,但不适用于严重的视神经病变等伴有视野显著缺损时的视力评定。

Using spatial frequency of PRVEP to assess visual acuity objectively in the traumatic eyes

Objective To explore the applicabilty of threshold of PRVEP P100 spatial frequency to evaluation of visual acuity in different eye lesions resulted from trauma.Methods 74 cases with definite diagnosis and accurate subjective visual acuity were selected from our cases who had experienced clinical forensic appraisals.Each subject was traumatized on an eye with the other eye of normal corrected visual acuity(≥ 4.9).All the cases were divided into 4 groups: post-traumatic ametropia group(23 eyes),post-traumatic retinopathy group(31 eyes),post-traumatic optic neuropathy group(20 eyes).The other 74 normal eyes were employed as control.The visual evoked potential examination for threshold of PRVEP P100 spatial frequency was conducted with reversal pattern grating of six check sizes.The linear correlation between the threshold of PRVEP P100 spatial frequency and logarithm visual acuity was statistically analyzed.Results There was a high positive correlation between the threshold of PRVEP P100 spatial frequency(X) and the logarithm visual acuity(Y)(r=0.84,P<0.01),indicating that PRVEP was an objective parameter for objective evaluation of visual acuity.Howerver,threshold of PRVEP spatial frequency varied with different eye lesions resulted from trauma.There was no statistical correlation(P>0.05) between threshold of PRVEP P100 spatial frequency and visual acuity in post-traumatic optic neuropathy group.Conclusion Threshold of PRVEP P100 spatial frequency can be used for evaluation of the visual acuity as an objective parameter in clinical forensic practice,but not for severely traumatic optic neuropathy with loss of visual field.