许多文献报道,对有视野缺损的青光眼患者进行mfERG检查,都发现了改变,Hood等[8]认为二阶核反应以视网膜内层细胞的反应为主,缺少内层视网膜成分或视神经乳头成分,二阶核反应就会减少。如果二阶核反应丢失,那么一阶核反应通常振幅变大或潜伏期延长;而当二阶核反应正常时,一阶核反应一般具有正常的峰潜时。Graham等[9]发现在青光眼患者中,早期即出现SOK的异常且异常的程度与神经纤维层变薄有关。但在早期患者中,FOK多是正常的,至晚期才会出现振幅的下降。我们观察到早期POAG组二阶核反应鼻上(SN )、鼻下(IN),颞下(IT),颞上(ST)4个象限以及总和反应波的P1波振幅密度比正常对照组显著降低(P<0.03),N1波振幅密度轻度降低(P<0.05),N1、P1波潜峰时比正常对照组延长(P < 0.05)。这说明在早期POAG患者中,视网膜内层的功能显著减退。我们发现许多患者自动视野计检测已出现明显的视野损害时,这些mfERG的异常仍相当微小。而且,mfERG的结果异常处并不与自动视野计检测出的视野缺失处相对应。Fortune等[10]认为在青光眼患者中mfERG成分如视神经乳头成分的缺失可能实际上导致峰谷值升高,这已在低对比度下的人类反应[11]和其它灵长类动物[12]的研究中得到证实。因此很明显,试图将局部mfERG异常与局部视野敏感度缺损相关联,仍是不现实的。mfERG二阶核反应是一种检测青光眼的敏感方法,可以为早期青光眼的诊断提供有效的依据,总的来说mfERG在青光眼诊断的应用还处于研究讨论阶段,mfERG之优点在与其检查的客观性,但它局限性也已经显现出来,尤其是对于它的各波形的起源及发生机制,仍有很多争论,这还有待于我们进一步的研究。
【参考文献】 1 Palmowski AM. Sutter EE. Bearse MA Jr, Fung W. Mapping of retina function in diabetic retinopathy using multifocal electroretinogram. Invest Ophthalmol Vis Sci ,1997;38:2586-2596
2 Klistomer A, Crewther DP. Crewther SG. Temporal analysis of the topographic ERG: chromatic versus achromatic stimulation. Vision Tes ,1998;38:1047-1062
3 Tan Q, Liu SZ, Xu XL, Xia CH. Spatial characteristics of multifocal electoretinogiam in normal subjects. Int J Ophthalmol(Guoji Yanke Zazhi) ,2004;6(4):626-630
4 Tan Q, Xia CH, Ding ZX, Liu SZ, Xu XL. Character of multifocal electroretinogram in age-related changes of normal subjects. Int J Ophthalmol (Guoji Yanke Zazhi) ,2005;5(2):275-277
5 Horiguchi M, Suzuki S, Kondo M, Tanikawa A, Miyake Y. Effect of glutamate analogues and inhibitory neurotransmitters on the electroretinograms ellicited by random sequence stimuli in rabbits. Invest Ophthalmol Vis Sci ,1998;39:2171-2176
6 Hood DC, Frishman LJ, Saszik S, Viswanathan S. Retinal origins of the primate multifocal ERG: implications for the human response. Invest Ophthalmol Vis Sci ,2002;43:1673-1685
7 Chan HH, Brown B. Pilot study of the multifocal electroretinogram in ocular hypertension. Br J Ophthalmo1 ,2000;84(10):1147-1153
8 Hood DC. Assessing retinal function with the multifocal technique. Prog Retin Eye Res ,2000;19(5):607-646
9 Graham SL. Klistomer A. Electrophysiology:a review of signal origins and applications to investigating glaucoma. Aust J Ophthalmol ,1998;26:71-85
10 Fortune B, Johnson CA, Cioffi GA. The topographic relationship between multifocal electroretinographic and behavioral perimetric measures of function in glaucoma. Optom Vis Sci ,2001;78:206-214
11 Hood DC, Greenstein V, Frishman L, Holopigian K, Viswanathan S, Seiple W, Ahmed J, Robson JG. Identifying inner retinal contributions to the human multifocal ERG. Vision Res ,1999;39:2285-2291
12 Hood DC, Bearse MA, Sutter EE, Viswanathan S, Frishman LJ. The Optic nerve head component of the monkey's multifocal electroretinogram. Vision Research. Vision Res ,2001;41:2029 -2041 上一页 [1] [2] [3] |