视网膜电图b波振幅和刺激光强关系研究

应用视觉电生理记录分析系统，记录5个对数单位范围的刺激光强作用下，20例(30只眼)新西兰大白兔和20例(30只眼)正常成人的系列光强视网膜电图，求出视网膜电图b波的光强-振幅函数关系和曲线方程。结果：在低和中等刺激光强下，b波振幅和刺激光强的函数关系为“S”型曲线，曲线方程符合Naka-Rushton等式：R／Rmax=1^n／(I^n K^n)。在较强刺激光强下，曲线出现第二上升支。该第二上升支是视网膜视杆系统反应和视锥系统反应共同作用的结果。     

正常SD大鼠多焦闪光视网膜电图特性

目的　探讨SD大鼠的多焦视网膜电图 (mfERG)特性及记录方法的可靠性。方法　正常SD大鼠 10只 ,按照本实验室建立的方法在暗适应条件下记录mfERG ,并比较注视点改变和重复记录对结果的影响。为避免记录时间和麻醉药物的可能影响 ,每次记录间隔 3d。结果　注视点位于屏幕中心时 ,mfERG总和反应P1波的潜伏期为 (4 5 44±2 77)ms ,幅值为 (14 4 16± 6 19) μV ,上半视野的P1波的潜伏期较下半视野显著延长 (P <0 0 5 ) ,幅值随离心度的增加而减少 (P <0 0 5 )。重复记录结果没有显著性差异 (P >0 0 5 )。注视点偏离屏幕刺激中心点 5mm后 ,对检查结果有明显影响 ,与注视点位于刺激中心点时比较 ,旁中心注视的各象限以及第 1环和第 5环N1波的潜伏期在各位置间即有变化 (P <0 0 5 )。结论　正常SD大鼠mfERG幅值呈离心分布可能与光感受器在视网膜的密度有关 ,潜伏期呈上下分布与大鼠习性有关。实验室建立的mfERG记录方法能够可靠地记录SD大鼠视网膜的功能变化     

视网膜电图与刺激光强的关系

视网膜电图（ＥＲＧ）各成分有不同的光敏感性。刺激光强由弱到强时，记录到的ＥＲＧ成分依次为暗适阈值反应（ＳＴＲ），ｂ波，ａ波和振荡电位（ＯＰｓ）。ＳＴＲ振幅和潜时与刺激光强呈线性相关，ｂ波振与刺激光强函数关系符合“Ｓ”型曲线方程Ｒ／Ｒｍａｘ＝Ｉ＾ｎ／（Ｉ＾ｎ＋Ｋ＾ｎ），但当刺激光强较强时，该曲线出现第二上升支。不同的刺激光强，ａ波有不同的形成，中等强度的刺激光强，ａ波为双谷型，由ａ１波和波２波组成。     

正常成年SD大鼠明视闪光视网膜电图特征

目的:探讨正常成年SD大鼠的明视视网膜电图(Electroretinogram,ERG)特征.方法:选取正常9～12周SD大鼠60只,使用罗兰视觉电生理仪记录大鼠右眼的明视闪光ERG.使用SPSS统计分析a波、b波和明视负波反应(Photopic negative response,PhNR)的隐含期和振幅.比较雄性和雌性SD大鼠明视ERG特征.结果:每只SD大鼠均能记录到稳定的a波、b波和PhNR,其中a波的隐含期和PhNR的隐含期及振幅均符合正态分布,而其余指标均不符合正态分布.PhNR的隐含期为124.6±8.5ms,其变异系数最小(0.07).PhNR的振幅为(11.3±4.2)μV,变异系数为0.37.雄性和雌性SD大鼠明视ERG的各反应波之间无显著差异.结论:在正常成年SD大鼠,明视闪光ERG是一项客观评价大鼠明视状态下视网膜功能的手段,PhNR可以作为一项稳定的评价内层视网膜功能的指标.     

正常SD大鼠视网膜电图随生长发育变化的特点

目的研究正常SD大鼠视网膜电图(ERG)随生长发育的变化特点。方法分别测量40只(40眼)SD大鼠在出生后第14、21、28、35和56d(P14、P21、P28、P35、P56)的ERC。结果正常SD大鼠Max-ERGa波、OPsO1波潜伏期在各个时间点无明显差异;Rod-ERGb波、Max-ERGb波、Cone-ERGb波、OPsO2波潜伏期和波幅值以及OPsO1波和Max-ERGa波幅值、Flick-ERG幅值在P14分别和其他时间点有差异。结论实验在一定程度上证实了正常SD大鼠ERG中各波形的起源。明确了各波形的成熟时间,P21时正常SD大鼠ERG基本发育成熟。     

不同通频带和刺激光强对小鼠视网膜电图OPs波的影响

目的 通过改变不同通频带和不同光强刺激，探讨昆明小鼠、BALB／C、C57BL／6J小鼠视网膜电图OPs检查的最适通频带和最适闪光强度。方法 昆明小鼠、BALB／C、C57BL／6J小鼠各10只，在暗适应条件下，在不同通频带条件下，分别做视网膜振荡电位(OPs)记录，找出小鼠最适通频带，再在此通频带基础上，进行不同光强下视网膜振荡电位(OPs)记录。结果 不同品系的小鼠在不同光强情况下，其振荡电位随着光强的增强其OPs波波形和幅值随之增高，02波的潜伏期逐步缩短，在2．0(标闪)cd／m^2每秒光强条件下较为稳定。其中BALB／C小鼠幅值最小，C57BL／6J小鼠幅值最大。在通频带75～300Hz时，其振荡电位幅值和潜伏期最为稳定。结论 建议在小鼠视觉电生理检查时，其振荡电位的闪光强度应为2．0(标闪)cd／m^2每秒，通频带应为75～300Hz。     

正常婴儿的闪光视网膜电图特性

目的：探讨4至5个月龄正常婴儿视网膜功能特性。方法：选取正常4个月龄婴儿17例(34只眼)、5个月龄婴儿13例(26只眼)和正常成年对照39例（78只眼)进行闪光视网膜电图（electroretinogram,ERG)检测，记录视杆细胞反应、视锥细胞反应及最大混合反应。对比分析两个婴儿组的ERG各个反应的b波振幅及潜伏期，并与正常成人组作比较。结果：两个正常婴儿组ERG各个反应的b波振幅和潜伏期与正常成人组相比都有非常显著差异，婴儿组的振幅低、潜伏期长。两个正常婴儿组之间相比，视锥反应有显著性差异，5个月龄组振幅较高，潜伏期较短；而视杆反应和最大混合反应无显著性差异。4个月和5个月龄婴儿组的视杆反应b波平均振幅分别为正常成人38．9％和36．7％，而视锥反应b波的平均振幅分别为正常成人的62．6％和71．5％。结论：在4至5个月龄期，婴儿ERG的各个反应都没达到正常成年人水平。视锥细胞反应与视杆细胞反应相比，在4至5个月龄期，增长得更快，发育得更成熟。     

大鼠生长发育早期视网膜电图变化特点

目的研究正常SD大鼠早期睁眼前视网膜电图(electroretinogram,ERG)随生长发育的变化特点。方法分别测量30只(30眼)SD大鼠在出生后第9天、第10天、第11天、第12天和第13天的杆体、最大混合反应、明适应及闪烁光ERG和振荡电位。结果出生后第9天时即可记录到闪烁光ERG的存在,潜伏期为(34.20±7.10)ms,振幅(0.59±0.16)μV;出生后第10天时可以记录到最大混合反应-ERG a波潜伏期(23.30±3.90)ms,振幅(1.58±0.58)μV,振荡电位O1波潜伏期(18.60±3.00)ms,振幅(0.53±0.22)μV。杆体-ERG、最大混合反应-ERG b波、明适应-ERG在大鼠眼睑开放前无法引出。结论本实验初步探讨了大鼠早期睁眼前ERG的记录方法及其生长发育的变化特点,为进一步研究ERG的波形起源提供了一定的依据。     

正常兔双眼视网膜电图对比及视网膜缺血-再灌注模型的建立

目的探讨正常兔双眼ERG有无差异，建立兔视网膜缺血-再灌注的血管结扎模型。方法20只兔，双眼均行ERG测定后随机分成A、B两组，A组兔10只，均右眼暴露视神经后不结扎。B组兔10只，均左眼视神经结扎60min。分别测定再灌注0h，3h，24h，48h，168hERG a、b波振幅(aA、bA)值。结果(1)正常兔左、右眼ERG aA、bA值差异无显著性，但个体之间存在一定差异。(2)未结扎组视网膜缺血-再灌注0h，3h，24h，48h，168h的ERG aA、hA值差异无显著性。(3)结扎后兔ERG aA、bA值均明显下降，再灌注24h最低，后逐渐上升。结论(1)正常兔双眼ERG差异无显著性，但不同个体间有较大差异。(2)成功地建立了兔视网膜缺血-再灌注的血管结扎模型，发现缺血60min，再灌注24h时视网膜功能受到进一步损伤。     

The luminance-response function of the dark-adapted human electroretinogram

A hyperbolic equation of the form (R/Rmax) = Ln/(Ln + Kn) has been used to describe the b-wave luminance-response function of the dark-adapted human electroretinogram (ERG). However, this equation accurately describes the function only at low to moderate flash luminances. At high flash luminances, a second amplitude increase or "limb" appears in the function. The results of the present study demonstrate that this limb does not represent a cone system response. First, the spectral sensitivity of the entire luminance-response function is rod-determined in normal subjects. Second, the limb was present in a rod monochromat, in whom cone system ERGs were indistinguishable from noise. Instead, the nonmonotonic nature of the luminance-response function may result from a luminance-dependent algebraic summation of the components that underlie the ERG waveform of the rod system.     

Fundus pigmentation and the dark-adapted electroretinogram

Dark-adapted electroretinograms were obtained over a 3.6-log range of stimulus intensities from 17 black and 15 white normal subjects. Subjects were grouped on the basis of light or dark fundus pigmentation, determined from digitized fundus photographs. B-wave amplitudes for each group were fitted by the Naka-Rushton equation, and the measures Vmax, log K, and n were determined. The luminance-response functions revealed that subjects with light fundi had larger b-wave amplitudes at all luminance levels. There was a significant difference between groups for Vmax and n but not for log K. A comparison of b-wave implicit times showed no significant difference between subjects with dark and light fundi. Ancillary tests and multiple regression analysis suggested that the relationship between Vmax and fundus pigmentation could not be attributed to age, gender, refractive error, axial length or intraocular pressure. The results have implications for the collection of normative electroretinographic data and for the interpretation of electroretinogram results.Abbreviations AL axial length - FPH fundus pigmentation heterogeneity - IOP intraocular pressure - L-R function luminance-response function - ND neutral density - RE refractive error - sph eq spherical equivalent.     

视网膜色素上皮变性大鼠随生长发育的视网膜电图改变

背景RCS—rdy-P’大鼠随着生长发育会逐渐发生视网膜色素变性（RP）,记录其生长发育过程中的视网膜电图（ERG）改变可为该模型鼠的进一步研究奠定基础。目的观察RCS—rdy-P’大鼠视网膜发育过程中的ERG变化,研究ERG随发育的变化特点。方法采用RETI-port系统、环形角膜电极和不锈钢针状电极分别记录生后21、32、37、45、60d的RCS-rdy-P’大鼠的系列暗适应ERG,每个年龄组6只鼠。取相同时间点及数量的同种系正常的RCS-rdy-P’大鼠作为正常对照。暗适应不同时间的ERG对比采用RCS-rdy＋P’生后60d大鼠共9只,每组3只。结果在刺激光强、刺激频率、体温相同的情况下,RCS-rdy-P’大鼠ERGb波振幅与暗适应时间有关,随着暗适应时间的延长,b波振幅增加,当暗适应时间超过12h时,即使暗适应时间增加,b波振幅不再增长,说明暗适应超过12h可以得到RCS-rdy＋-P’大鼠一个较为稳定的ERG波形。与RCS—rdy＋一P’大鼠比较,RCS—rdy-P’大鼠在生后21d时ERG已出现a波、b波振幅的下降,同时隐含时明显延长,以a波改变为主。随着RCS—rdy-P’大鼠年龄增长及RP的进展,ERGa波、b波振幅进一步下降,隐含时延长,RCS—rdy-P’大鼠生后60d时,其ERG反应记录不到。对照组大鼠在21d时,ERG的a波、b波均振幅较低;生后32d时RCS—rdy-P’大鼠b波振幅增加,但隐含时缩短;到生后45d仅小幅增加,45～60d再次出现b波振幅显著增加,隐含时缩短。结论RCS—rdy一一P’大鼠随着年龄的增长发生视网膜功能的变化,其暗适应ERG改变符合RP的进展过程。     

SD大鼠暗视阈值反应波形记录的特征

目的:研究SD大鼠暗视阈值反应(scotopic threshold re-sponse,STR)的特点。方法:SD大鼠21只,随机分成3组,每组7只,完全暗适应12h,麻醉后采用RETI-port系统(Roland Consult,德国)分别记录不同通频带(0.1～50,0.1～100,0.1～300,1～50,5～50Hz),不同刺激频率(0.25,0.50,0.75,1,2Hz),不同闪光强度(-6.3,-6.0,-5.7,-5.4log(cd·s)/m2)下的STR。结果:本实验条件下可以记录到稳定的STR,分为正向的pSTR和负向的nSTR。通频带对STR有影响,随着高频段的增大,附加在波形上的杂波比较多,pSTR和nSTR潜伏期和振幅变化不明显。随着低频段升高,nSTR逐渐消失,尤其是低频段达到5Hz时,振幅有显著差异(P<0.05)。刺激频率小于1.0Hz时,pSTR和nSTR波形比较稳定,而且nSTR振幅和潜伏期没有明显差异。当刺激频率大于2Hz时,负向波消失,并且正向波振幅明显升高(P<0.05)。随着刺激光强的增加,pSTR振幅增大,尤其是在光强为-5.7,-5.4log(cd·s)/m2时,振幅有显著差异(P<0.05),nSTR逐渐平坦消失,未见a波。结论:SD大鼠STR波形记录与刺激和记录参数密切相关,在完全暗适应条件下,低光强刺激(-6.3和-6.0log(cd·s)/m2)、低通带(0.1～50Hz)、适当刺激频率(<1Hz)下可以记录到完整的稳定的STR波形。     

mGluR5对大鼠视网膜对光反应的调控

目的探索代谢型谷氨酸受体5（mGluR5）对大鼠暗适应视网膜电图（ERG）不同成分的贡献。方法实验研究。出生后30日龄大鼠（RCS-rdy+-p+）12只,暗适应大于12 h后,分别行视网膜下腔注射mGluR5激动剂CHPG[（R,S）-2-chloro-5-hydroxyphenylglycine] 200 µmol（6只,CHPG组）和抑制剂MPEP[2-methyl-6-（phenylethynyl）-pyridine] 200 µmol（6只,MPEP组）,对侧眼注射同等体积PBS作为对照。注射后2 d采用RETI-scan系统记录其系列刺激光强度下（-4.5、-2.5、-0.5、-0.02、0.5 1 logcd×m×s-2）的暗适应ERG。导出数据,采用配对t检验进行双眼间数据比较。结果CHPG组,a、b波幅值在不同光强下均显著降低（除最低光强）（-4.5＜t＜-2.3,P＜0.05）,进一步分析得出a、b波最大幅值（Rmax和Vmax）均明显降低（-4.5＜t＜-2.3,P＜0.05）,但其敏感度均未出现明显变化,且b/a未见明显变化。MPEP组,a、b波幅值在不同光强下均显著升高（除最低光强）（-3＜t＜-2,P＜0.05）,进一步分析得出a、b波Rmax和Vmax均明显升高（-3＜t＜-2,P＜0.05）,但其敏感度均未出现明显变化,且b/a未见明显变化。2组的振荡电位（OPs）与相应的对照眼比较未见明显差别。结论mGluR5激动后,ERG a、b波幅值明显降低,mGluR5主要调控外层视网膜的对光反应。     

人工泪液对大鼠视网膜电图的影响

目的 观察人工泪液对大鼠视网膜电图（ERG）的影响.方法 动物实验研究.SD大鼠充分暗适应后,记录单眼ERG.ERG记录采用自制银丝电极和不锈钢针状电极,其中银丝电极为记录电极,置于角巩膜缘,各组ERG记录眼人工泪液用量不同：第1组为未滴人工泪液组;第2组为适量组,滴少量人工泪液,使电极与角巩膜缘接触良好;第3组为过量组,滴入大量人工泪液,使之充满整个结膜囊.ERG a、b波幅值和峰时采用单因素方差分析比较组间差异,两两间差异采用LSDt法进行比较.结果 使用人工泪液的两组动物ERG基线平滑,干扰波不明显;然而人工泪液使用过量组a、b波振幅均明显降低,与其他两组相比差异均有统计学意义（t=4.112,P＜0.01;t=3.018,P＜0.05）.结论 视觉电生理实验室经屏蔽和有效接地后,动物ERG记录中使用人工泪液可以进一步降低干扰,但人工泪液使用过量会影响ERG振幅大小.     

The negative response of the flash electroretinogram in glaucoma

The existence of a negative ERG component following the b-wave has been known for a long time. Recently, in unilateral macaque experimental glaucoma, a negative response in flash electroretinograms under scotopic as well as photopic conditions has been shown to be greatly reduced or absent compared to the healthy fellow eye. The aim of this pilot study was to test whether a late negative electroretinogram component is reduced also in human glaucoma patients under different stimulus conditions. Dark-adapted ganzfeld flash electroretinograms were recorded after 30 min of dark using two test conditions, obtained as optimal in pilot studies on controls. Under the scotopic condition I white Xenon-flashes of intensity 0.53 Log photopic Td s were presented on a low white background of 1.38 Log scotopic Td. Under the more photopic condition II orange flashes of intensity –0.37 Log photopic Td s were presented on a blue-adapting background of 2.5 Log scotopic Td. Nine controls and 18 patients with advanced glaucoma were analyzed. The amplitude of the negative response was not significantly reduced in glaucoma patients (condition I: –28.5±23.7 V; condition II: –25.2±19.7 V) compared to controls (condition I: –41.4±36.6 V; condition II: –31.3±26.2 V). The peak latency of the responses under condition I and II did not differ significantly between patients and controls. Thus, the late negative electroretinogram component in ganzfeld flash electroretinograms obtained under scotopic and more photopic conditions does not seem to distinguish as easy between human controls and glaucoma patients as animal experiments suggest.     

The oscillatory potentials of the dark-adapted electroretinogram in retinopathy of prematurity

PURPOSE: To study the development of the electroretinographic (ERG) oscillatory potentials (OPs) in two rat models of ROP and in human subjects with a history of ROP. METHODS: Sprague-Dawley rats (n = 36) were studied longitudinally. Rat models of ROP were induced, either by exposure to alternating 50%/10% oxygen (50/10 model) from postnatal day (P) 0 to P14 or by exposure to 75% oxygen (75 model) from P7 to P14. Control rats were reared in room air. Infant and adult human subjects with and without a history of ROP (n = 91) were also studied. Dark-adapted ERGs were recorded and filtered to demonstrate the OPs. Discreet Fourier transform (DFT) allowed evaluation of the OP power spectrum. OP energy (E), dominant frequency (F(peak)), and sensitivity (log i(1/2)) were evaluated. RESULTS: In 50/10 model rats, E was low compared with that in the 75 model rats and control animals. F(peak) (approximately 95 Hz) did not vary with age or group. Intriguingly, log i(1/2) in 75 model rats was greater than that in controls or 50/10 model rats. Human adults with a history of ROP had lower-energy OPs than did the control adults, but infants with a history of ROP had higher-energy OPs than did the control infants. F(peak) was lower (approximately 120 Hz) in infants than in adults (approximately 130 Hz). ROP did not affect log i(1/2) in humans. CONCLUSIONS: Differences between OPs in healthy rats and healthy humans were substantial, suggesting that OPs in rat models of ROP are unlikely to provide insight into the effects of ROP on human OPs. Indeed, neither ROP model studied showed a pattern of effects similar to that in human ROP.