似昼夜节律对正常SD大鼠视觉电生理的影响

目的 研究一天中不同时间段记录的正常SD大鼠视觉电生理结果间的区别,以揭示似昼夜节律对视网膜功能的影响。方法 实验研究。24只SD大鼠随机分为4组,每组6只（6眼）。对各组分别于8：00~12：00（上午）、14：00~18：00（下午）、20：00~24：00（午夜）、2：00~6：00（凌晨）4个时间段记录不同刺激参数的视觉电生理。各组间差异采用单因素方差分析,两两间差异采用post hoc检验分析。结果 下午及午夜的暗适应视网膜电图a波和b波的幅值要高于上午（P<0.05）,振荡电位O2波幅值在午夜最高（P<0.05）,20 Hz闪烁视网膜电图反应P1波和视觉诱发电位N1波的潜伏期凌晨明显较上午短（P<0.05）。结论 SD大鼠的视锥和视杆功能变化与似昼夜节律有关,其在夜间要较白天活跃,视觉电生理记录最好固定在每天的同一时间段进行。     

正常食蟹猴不同适应时间视网膜电图的 变化

目的：研究明/暗适应时间对正常成年食蟹猴闪光视网膜电图（ERG）结果的影响。方法：实验研究。 选取3只成年食蟹猴,分别于暗适应20、40、60 min后用国际临床视觉电生理会标准参数刺激,常 规程序记录暗适应ERG,在暗适应40 min后,分别明适应1、5、10 min记录明适应ERG。采用单因 素方差分析比较各时间段振幅与潜伏期变化。结果：不同暗适应时间,a、b波和震荡电位OPs的潜 伏期差异均无统计学意义（F=0.052,P=0.949）,暗适应时间小于40 min时,a、b波和OPs的振幅随暗 适应时间增加而显著增大（F=50.800,P<0.001）;暗适应40 min时,振幅达到最大,且不再随暗适应 时间增加而增大（F=0.016,P=0.899）。明适应a、b波的潜伏期同样不受明适应时间的影响（F=0.980, P=0.381）,a、b波的振幅在明适应5 min后达到最大（F=4.789,P=0.036）且随时间延长趋于平稳 （F=0.135,P=0.717）。结论：在一定时间内,明/暗适应时间对食蟹猴闪光ERG结果影响较大,故对 食蟹猴暗适应ERG记录的时间不宜少于40 min,而明适应ERG在5 min后即可记录。     

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.     

体温变化对正常大鼠视网膜电图的影响

目的研究体温变化对正常SD大鼠视网膜电图的影响。方法12周龄SD大鼠25只,随机分为5组,每组5只。应用精密温度计测量SD大鼠肛温。实验1:大鼠体温维持在(35±1)℃,每间隔10min测量一次视网膜电图。实验2:从35℃、30℃、25℃到20℃依次降低大鼠体温,记录每个体温梯度的视网膜电图。结果实验1:视网膜电图的a波、b波和振荡电位潜伏期和幅值没有明显改变。实验2:随着体温的降低,视网膜电图的幅值明显降低、潜伏期显著延长。结论体温变化明显影响视网膜电图的潜伏期和幅值。应用视觉电生理技术评价视网膜功能时,尤其是应用小动物(例如大鼠)进行实验研究时,维持其体温恒定非常重要。     

外伤性视网膜震荡的视觉电生理改变

目的：探讨外伤性视网膜震荡的视觉电生理改变。方法：对68例单眼外伤性视网膜震荡治疗前后的视觉诱发电位（VEP）及视网膜电图（ERG）改变进行观察。结果：外伤性视网膜震荡VEP异常率达91.18％,ERG异常率达85.29％,VEP和ERG联合检测异常率可达100％。电生理异常改变为,VEP P100波及ERG b波潜伏期延长（P＜0.05）,幅值降低（P＜0.01）;治疗后P100、b波均有明显改善,潜伏期（P＜0.05）,幅值（P＜0.01）。结论：提示VEP P100波、ERG b波可作为外伤性网膜震荡早期诊断有价值的观察指标,对病情判断、疗效观察亦有一定的临床意义。外伤性视网膜震荡电生理检查改变是可逆的。     

视网膜色素变性的视觉电生理和心理物理学检测

目的：观察视网膜色素变性(retinitis pigmentosa，RP)患者视觉电生理与心理物理学的改变，探讨其视网膜的病理生理变化。 方法：对58例(113眼)作暗适应红光和蓝光视网膜电图(electroretinogram,ERG)，明适应白光ERG，黄斑中心色光阈值(color light threshold,CLT)和D-15色相配列检测井进行分析。 结果：113只眼暗适应红光ERG均出现异常。111只眼(98.23%)暗适应蓝光及暗适应白光ERG异常，88只眼(77.87%)黄斑中心CLT异常；作D-15色相配列检查的55只眼中30只眼(54.54%)有不同程度色觉异常。暗适应红光ERGb波波幅与病程、视力及视野间均无明显的相关性。 结论：RP不仅存在视网膜杆体功能异常，锥体功能亦有紊乱．暗适应红光ERG是较全面反映RP患者视网膜功能的简便、敏感的客观检测方法。 （中华眼底病杂志，1995，11：143-146）     

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。     

兔视网膜下非活动视觉假体载片植入对ERG的影响

目的 用视网膜电图(ERG)探究视网膜下非活动视觉假体载片植入对视网膜功能的影响.方法 24只新西兰白兔,随机分为手术组和伪手术组(各12只兔).记录各组术前及术后7、15、30、60d(每时间点3只兔)ERG b波振幅.统计各组ERG的a波和b波振幅数值,进行t检验和单因素方差分析.结果 各组间及手术组、伪手术组时间点间ERG a波振幅未见明显差异.手术组术后ERG b波振幅较术前正常对照组有不同程度升高(P=0.038),手术组与伪手术组间及伪手术组与术前正常对照组间差异无统计学意义(P=0.649和P=0.369),手术组和伪手术组时间点间差异无统计学意义.结论 手术组视网膜下非活动视觉假体载片植入后ERG b波振幅有不同程度的升高,提示载片植入后在一定时间范围内可能保护视网膜的功能.     

正常大鼠和急性高眼压诱导的视网膜缺血再灌注损伤大鼠模型的视网膜电图

目的：探索闪光视网膜电图（F－ERG）对大鼠视网膜功能评价的客观性和可靠性;并探讨急性高眼压诱导的视网膜缺血再灌注损伤大鼠在视网膜神经细胞保护研究方面的可行性。方法：采用Nicolet Spirit电生理诊断仪,检测34只Sprague-Dawley（SD）大鼠的F－ERG的最大反应和Ops波;用提高眼压的方法造成视网膜缺血60分钟,然后恢复眼压形成血流再灌注造成大鼠动物模型,随后检测灌注后24h,72h以及168h时的F－ERG的最大反应和Ops波。结果：每只正常大鼠均可引出典型的ERG的a波,b波以及Ops波,但个体之间存在一定差异;模型大鼠的各波比灌注前均显著降低,而且灌注后各时间点也有一定差异。结论：本模型操作简单,可控性好以及F－ERG的最大反应和Ops波能客观反映大鼠视网膜功能,因此可以用来进行视网膜神经细胞保护方面研究。     

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.     

再适应视网膜电图——一种客观的暗适应功能检测方法

目的探讨用电生理方法检测糖尿病视网膜病变（ＤＲ）患者的暗适应过程。方法利用标准杆体反应的记录条件检测再适应视网膜电图（Ｒｅ－ＥＲＧ）。５２例正常眼Ｒｅ－ＥＲＧ的ｂ波振幅随暗适应时间的延长呈现由无到有、由小到大并趋于稳定的过程，达到最高值的时间平均为（２７．０８±２．５８）ｍｉｎ。结果不同时期的ＤＲ眼Ｒｅ－ＥＲＧ结果显示ＤＲ患者的暗适应功能下降，下降幅度与病变的严重程度呈平行关系。未出现ＤＲ的糖尿病患者组与正常组相比其Ｒｅ－ＥＲＧ的ｂ波振幅无统计学差异结论Ｒｅ－ＥＲＧ是一种客观的暗适应功能检测方法，但不能作为ＤＲ的早期诊断手段。     

利用锥体细胞失功能大鼠和先天性静止性夜盲大鼠对视锥与视杆通路振荡电位的分离研究

背景 振荡电位(OPs)是评估视网膜缺血缺氧性疾病视网膜功能变化的重要工具,利用视网膜退行性病变动物模型对视锥、视杆通路起源的OPs特点进行研究非常重要. 目的 在两种自发性视网膜退行性病变模型大鼠中分离视锥、视杆通路,对比分析视杆、视锥通路起源的OPs波的特点. 方法 采用雄性SD大鼠、锥体细胞失功能(RCD)大鼠、先天性静止性夜盲(CSNB)大鼠各6只,以RETI-scan视觉生理记录系统分别在暗适应(12h)和明适应(10 min)条件下,用不同强度的刺激光(-35、-25、-15、-5、0、5 db)进行刺激,记录各组大鼠的闪光视网膜电图(FERG),通过Matlab 7.0的Butterworth滤波提取OPs,采用快速傅里叶变换(FFT)对所得OPs进行频谱分析.结果 暗适应条件下SD大鼠和RCD大鼠的ERG均可见a波和b波,但CSNB大鼠b波阙如;明适应条件下,SD大鼠和CSNB大鼠可见b波,但RCD大鼠各波阙如.暗适应较高刺激光强度下,SD大鼠和RCD大鼠均有低频(主频)和高频(次频)两个明显的频峰,分别为75 ～ 110 Hz、90～120 Hz和90～ 120 Hz、110 ～ 135 Hz;不同刺激光强度下,CSNB大鼠只有一个频峰,为70～100 Hz.而明适应不同刺激光强度下,SD大鼠和CSNB大鼠均只有一个频峰,分别为75～95 Hz和70～85 Hz.明适应条件下与SD大鼠比较,CSNB大鼠b波隐含时延长,b波振幅明显下降,差异均有统计学意义(P＜0.05);暗适应条件下,RCD大鼠b波隐含时和振幅与SD大鼠比较,差异无统计学意义(P＞0.05);与SD大鼠比较,RCD和CSNB大鼠OPs波振幅下降,隐含时延长,差异均有统计学意义(P＜0.05);明适应条件下不同刺激光强度下CSNB大鼠OPs波的隐含时明显长于SD大鼠,振幅明显低于SD大鼠,差异均有统计学意义(P＜0.05). 结论 视锥、视杆通路起源的OPs有不同特性,自发性视网膜退行性改变大鼠的视杆OPs有两个频峰,正常情况下,视杆通路对OPs的贡献比视锥通路大.     

Consecutive unilateral recording of the two eyes affects dark-adapted ERG responses,when compared to simultaneous bilateral recording

Purpose

Our aim was to compare the electroretinographic (ERG) responses of two eyes obtained by consecutive unilateral recordings to those obtained by a simultaneous bilateral recording in sheep.

Methods

Eight sheep underwent two full-field ERG recordings, using two recording strategies of the standard ISCEV protocol: consecutive unilateral recordings of one eye after the other, and simultaneous bilateral recording of both eyes. The order of recording strategy within an animal (unilateral/bilateral), eye recording sequence in the unilateral session (OD/OS), and amplifier channel assignment for each eye were all randomized. To test whether duration of dark adaptation and/or anesthesia affect the results, the ISCEV protocol was recorded bilaterally in six additional eyes following 38 min of patched dark adaptation, as was done for the second eye recorded in the consecutive unilateral recordings.

Results

The second recorded eye in the unilateral session had significantly higher scotopic b-wave amplitudes compared to the first recorded eye and to the bilaterally recorded eyes. A-wave amplitudes of the dark-adapted mixed rod–cone responses to a high-intensity flash were also significantly higher in the second eye compared to the first eye recorded unilaterally and to the bilaterally recorded eyes. Light-adapted responses were unaffected by the recording strategy. When the ISCEV protocol was recorded after 38 min of dark adaptation, the scotopic responses were higher than in the first eyes, and similar to those of the second eyes recorded unilaterally, suggesting that indeed the longer duration of anesthesia and dark adaptation are responsible for the increased scotopic responses of the second eye.

Conclusions

Consecutive unilateral ERG recordings of two eyes result in higher amplitudes of the dark-adapted responses of the eye recorded second, compared to the eye recorded first and to bilaterally recorded eyes. The differences in scotopic responses can be attributed to different duration of dark adaptation and/or anesthesia of the two consecutively recorded eyes. Photopic responses are not affected. Therefore, simultaneous bilateral ERG responses should be recorded when possible, especially for evaluation of scotopic responses.

     

Analysis of the photopic electroretinogram recorded before and after dark adaptation

To evaluate the effect of a long period of dark adaptation on the light-adapted electroretinogram (ERG), photopic ERGs were recorded before (light-adapted) and immediately after (light-readapted) 15 minutes of dark adaptation. The amplitude of the b-wave in the light-readapted ERG was 48% +/- 4% of that in the light-adapted ERG, and the peak time of the b-wave in the light-readapted ERG was delayed by an average of 3.49 +/- 1.09 ms. Segmental analysis of the b-wave showed that the last segment of the ascending limb of the b-wave (from the second oscillatory potential [OP] to the peak) was attenuated the most (61% +/- 8%). In fact, the reduction in the amplitude of the last segment alone accounted for more than 60% +/- 13% of the overall reduction observed for the entire b-wave. This last segment appears to correspond to OP4 in the 100- to 1000-Hz recordings. The amplitude of OP4 in the light-readapted ERG was 56.5% +/- 10% of that in the light-adapted ERG, a similar reduction to that observed for the last segment of the 1- to 1000-Hz b-wave. The results strongly support the concept that the b-wave of the photopic ERG may actually represent a composite of potentials whose individual contributions are best visualized when the ERG is recorded with the 100- to 1000-Hz bandwidth.     

Fundus albipunctatus in a 6-year old girl due to compound heterozygous mutations in the <Emphasis Type="Italic">RDH5</Emphasis> gene

We report a case study of Fundus Albipunctatus (FA) due to compound heterozygous mutations in RDH5, the gene encoding for the 11-cis-retinal dehydrogenase (RDH). A 6-year old Hispanic American female with a clinical presentation suggestive of FA underwent dark-adapted full-field flash electroretinography (ERG) at 30 and 120 min. The pattern of ERG abnormalities was consistent with the working diagnosis FA. However, only ERG responses to dim stimuli were profoundly affected, and maximal ERG responses were already near normal after only 30 min of dark adaptation. The patient also demonstrated a subnormal maximal ERG response b/a-wave ratio at 30 min that resolved after 120 min of dark adaptation. When measurable, dark-adapted post-receptoral responses were normal in timing under all circumstances, and became increasingly faster after prolonged dark adaptation. Cone-driven responses were completely normal at this young age. Sequencing of the RDH5 gene revealed two distinct missense mutations, a G238W mutation, previously reported in patients with FA, and a D128N mutation, which has not been reported before but is known to cause reduced 11-cis-RDH activity. These findings confirmed the clinical and functional diagnosis of FA and excluded that of retinitis punctata albescens (RPA). The behavior of dark-adapted ERG responses in FA displays characteristics that differ from those of RPA patients, which may be useful to differentiate functionally these two conditions at their common albipunctate stages.     

Concentration-dependent effects of dopamine on the direct current electroretinogram of pigmented rabbits during prolonged intermittent recording

The direct-current (DC) electroretinogram (ERG) was studied in 24 pigmented rabbits. Four experiments were performed, each including six animals. One eye was injected intravitreally with 0.1 ml dopamine (DA) with an estimated concentration in the vitreous body of 0.0025 mM, 0.025 mM, 0.25 mM and 2.5 mM, respectively. The contralateral eye was injected with the same amount of saline. Following the injection the animals were dark adapted for 30 min and then exposed to repeated light stimuli of low intensity for almost 3 hours (series I: 1 stimulus per 3 min, 10 s duration, light intensity 6.8 × 10² lux). After another 30 min period of dark adaptation repeated light stimuli of high intensity were presented to the eyes (series II: 1 stimulus per 70s, 10 s duration, light intensity 6.8 × 10⁴ lux) for 33 min. In the control eyes, a slow increase with time of the a-, b-and c-wave amplitudes was observed during series I. During series II, the a- b-and c-wave amplitudes were markedly reduced between the first and the second light stimulus, but subsequently grew to a peak. The behavior of the ERG in the eyes injected with dopamine was not different from that observed in the control eyes at the lowest concentration of the drug. At higher concentrations the b-and c-wave amplitudes were reduced compared with the control eyes, and did not show the slow increase with time observed in these eyes during series I. Peak responses observed during series II in the control eyes was increasingly suppressed in the eyes treated with dopamine. Results of ERG recordings suggest that dopamine influences retinal adaptation in rabbits in a dose dependent manner.     

580眼视网膜色素变性患者ERG改变的研究

统计和分析了580眼视网膜色素变性患者的视力、视野、暗适应和ERG检查结果。讨论了ERG与患者年龄、性别、视力、视野、暗适应之间的关系。指出ERG波型熄灭是视网膜色素变性的临床特征之一。ERG检查在视网膜色素变性患者的诊断(特别是早期诊断)、治疗以及预后等方面有重要意义。     

Temporal aspects of the electroretinogram in cone-rod dystrophy

Twelve patients with cone-rod dystrophy were studied in terms of the temporal aspects of electroretinography (ERG).The peak time of scotopic b-wave was within normal limits in all patients, while the amplitude was reduced in nine patients. The normal peak time of the scotopic-b wave may help explain rod involvement with normal or only slightly elevated final rod thresholds of subjective dark adaptation.The peak time of photopic b-wave and 30-Hz flicker response was normal in four patients and significantly delayed or nonrecordable in eight patients. Such variations of peak time in photopic and 30-Hz flicker ERG may reflect the stage of the disease or may be caused by the different hereditary mode.