视杆细胞多焦视网膜电图

多焦视网膜电图技术越来越多地应用于科研与临床，常规记录是在明视条件下，反映的是视锥细胞的功能。近年出现视杆细胞多焦视网膜电图技术。本综述该技术的检测条件、反应波形和三维功能地形图特征、影响因素、功能评价和应用前景。     

图形闪光刺激的视网膜电图

记录视网膜电图通常是采用闪光灯刺激的方法。近十年来,又出现了一种利用黑白相间的方格或条栅图形转换刺激记录视网膜电图的新方法。若把闪光和图形这两种刺激方法结合起来,即采用图形闪光刺激记录视网膜电图,其波形如何,有何临床意义,尚未见有报道。为此,我们对图形闪光视网膜电图(Pattern     

闪光视网膜电图在视网膜挫伤中的应用

本文通过对８８例９３眼钝挫伤视网膜电图变化进行分析，得出结论：视网膜损伤越重，Ｆ－ＥＲＧ异常率越高，Ａｍｓ、Ｂｍｓ延长百分数越大，Ａｕｖ、Ｂｕｖ下降百分数越显著；治疗前、后视力越差，Ａｍｓ、Ｂｍｓ延长百分数越大，ＡｕｖＢｕｖ下降百分数越显著；并且通过治疗前，后视力与Ａｍｓ、Ａｕｖ、Ｂｍｓ、Ｂｕｖ进行多因素逐步回归分析，发现Ｂｍｓ与治疗前，后视力关系最为密切，因而认为Ｆ－ＦＲＧ是判断视网膜损伤程度的一项客观指标，为视力预后判断提供依据。     

糖尿病患者闪光视网膜电图的临床研究

糖尿病患者闪光视网膜电图的临床研究浙江省人民医院眼科任炼儿浙江省人民医院眼电生理室郎林福，王德法糖尿病性视网膜病变（ｄｉａｂｅｔｉｒｅ＇ｔｉｎｏｐａｔｈｙ，ＤＲ）是糖尿病（Ｄ）最常见的严重并发症之一，也是主要的致盲原因之一．近年来，将视网膜电图Ｕｅｃ...     

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     

视网膜电图和多焦视网膜电图视杆细胞ON和OFF反应记录研究

目的:研究全视野视网膜电图(electroretinogram,ERG)和多焦视网膜电图(multifocal eletroretinogram,mf-ERG)视杆细胞ON和OFF反应记录条件并分析其波形特征。方法:2例正常人放瞳、暗适应30 min后,分别采用矩形刺激(rectangle stimulus)、锯齿状的 rapid on和rapid off刺激模式记录反应波形,并改变刺激强度和频率观察波形变化。采用模拟矩形刺激、锯齿状的rapid on和rapid off刺激模式记录mf-ERG波形。结果:ERG采用矩形和rapid-on刺激模式可记录到大的正向波,随刺激频率增加,振幅减小, 潜伏时变化不明显。采用rapid-off刺激模式记录到小的负向波,潜伏时80 ms左右,在负向波下降支近波谷处可见小的正向波。随刺激频率增加,负向波潜伏时延长,而小正向波振幅逐渐减小。当刺激频率大于3 Hz时,上述反应均出现类似振荡电位波形。mf-ERG采用模拟矩形和模拟rapid-on刺激模式可记录到大的正向波,其波形特征与ERG矩形刺激模式的波形类似;采用模拟rapid-off刺激模式仍可记录大的正向波,但其后出现较大陡峭的负向波。结论:采用锯齿状的rapid-on和rapid-off刺激模式可以记录到视杆细胞ON和OFF反应,视杆细胞OFF反应的负向波下降支近波峰处存在小的正向波,采用模拟的rapid-on刺激模式记录到mf-ERG视杆细胞ON反应。建议记录ERG视杆细胞ON和OFF反应采用0．5-1Hz 刺激频率和低强度刺激光。将来可利用这些刺激模式研究视网膜疾病,具有一定的临床价值。     

双氯芬酸钠兔眼玻璃体内注射对视网膜电图影响的研究

目的：检测不同深度双氯芬酸钠对实验兔视网膜电图的影响。方法：将28只新西兰白兔随机分为7组。将400－1000μg不同剂量的双氯芬酸钠溶液0.1ml分别注入第1－7组家兔右眼玻璃体内。左眼为对照组,均在玻璃体注入0.1ml生理盐水。分别在注药后1,3,7,14,21,28天进行ERG检查。结果：当兔眼玻璃体注入的双氯芬酸钠大于或／和等于700 μg时,ERG检查发现暗适应和明适应b波波幅明显下降。结论：兔眼玻璃体注入的双氯芬酸钠大于或／和等于700μg时,对视网膜有毒性作用。     

正常闪光视网膜电图的频域分析

应用快速傅里叶转换技术对正常视网膜电图进行频域分析，发现其ａ、ｂ波的优势频及能量集中在５－７５Ｈｚ；与ＯＰＳ波的分离点为７７ＨＺ，从而提出单纯记录ａ、ｂ波及ＯＰＳ波各自的较理想的通频带。     

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.     

Flash electroretinography: normative values with surface skin electrodes and no pupil dilation using a standard stimulation protocol

Objectives: To demonstrate the clinical feasibility of using surface electrodes for recording flash electroretinography (ERG), using the stimulation standards of the International Society for the Clinical Electrophysiology of Vision (ISCEV), without pupillary dilation. Methods: Eighteen physiologically normal volunteers were tested. Surface recording electrodes were placed over the middle third of the lower eyelid of each eye, and the reference electrode placed on the temple. The recording filters and method of stimulation for the standard flash cone, 30 Hz flicker, rod, standard combined and oscillatory responses were those recommended by the ISCEV. Four patients with a history of visual dysfunction were also examined. Results: The amplitudes of the responses were noted to have a high signal to noise ratio, allowing us to average only a few responses. The waveform configurations were almost identical to those published using other recording methods. Patients with retinitis pigmentosa and early onset retinal dystrophy had abnormal responses, whereas patients with Stargardt’s Syndrome and spasm of accommodation had responses within normal limits. Conclusions: This study has established the clinical feasibility of performing flash ERG using surface skin electrodes, with no pupillary dilation and using the stimulation standards of the ISCEV.     

Contribution of voltage-gated sodium channels to b- and d-waves of frog electroretinogram under different conditions of light adaptation

The effect of blockade of voltage-gated sodium (Na_v) channels by tetrodotoxin (TTX) on the V-log I function of the ERG b- and d-waves was investigated in light and dark adapted frog eyecups. TTX diminished the b- and d-wave amplitude under both conditions of adaptation at all stimulus intensities except for the middle intensity range in dark adapted eyes, where it had no effect on the b-wave amplitude. TTX delayed the time course of the responses, obtained with low intensity stimuli and widened the dynamic range of the b-wave. The inhibitory effect of TTX on the cone-mediated, but not rod-mediated b- and d-wave amplitude persisted after the blockade of proximal retinal activity by NMDA, indicating that it may be due to a blockade of Na_v channels on the ON and OFF bipolar cells.     

眼球震颤婴幼儿的视网膜电图

目的:了解眼球震颤婴幼儿视网膜电图(Electroretinogram,ERG)测试的特点及其临床应用意义。方法:根据国际临床视觉电生理学会ERG标准化方案,应用日本光电公司生产的Neuropack MEB-2200K电生理仪对出生2个月至72个月的眼球震颤婴幼儿共46例(92只眼)进行测试。结果:46例(92只眼)眼球震颤婴幼儿中,除1例(2只眼)在闪烁光刺激时无法记录到ERG闪烁光反应外,其余病例皆可记录到5种类型的ERG。其中视杆细胞ERG、标准混合ERG、振荡电位、单次闪光视锥ERG和30Hz闪烁光反应的异常率分别为65%,86%,61%,77%和62%。若对每1只眼5种类型ERG进行综合评估,有5只眼表现为单纯视杆反应降低、11只眼表现为以视杆反应改变为主的杆锥反应异常、14例表现为单纯视锥反应降低、23只眼表现为以视锥反应改变为主的锥杆反应异常、8只眼表现为单纯混合反应异常、8只眼表现为全部记录不到反应的熄灭型,各有5只眼出现全部ERG的轻度下降、中度下降、重度下降,仅8只眼记录到正常ERG。结论:眼球震颤婴幼儿的ERG异常率达91%,表明视网膜的异常在眼球震颤的发病机制中起着重要的作用。     

Effects of the intravitreal administration of dopaminergic ligands on the b-wave amplitude of the rabbit electroretinogram

In the retina of mammals, dopamine (DA) is generally released by amacrine cells and is known to alter the physiology of most retinal cells. It is well known that DA reduces the amplitude of the b-wave of the electroretinogram (ERG) in rabbit. However, the specific receptor subtypes that mediate this action have not yet been elucidated. To do this, we recorded flash ERGs before and after the intravitreal injection of D1-like DA receptor agonists (SKF38393, A77693) and antagonist (SCH23390), and of D2-like agonist (R(-)-propylnorapomorphine hydrochloride; NPA) and antagonist ((S)-(-)-sulpiride). Contralateral control eyes were injected with the vehicle only. Both D1 agonists provoked a reduction of the ERG b-wave amplitude (34.0% and 59.2% of the pre-injection level, respectively). The D2-like agonist NPA had no significant effects on ERG components. Unexpectedly, both D1- and D2-like antagonists also reduced the b-wave amplitude (28.9% and 59.8%). Overall, these data suggest that the previously described effect of DA on the rabbit ERG b-wave came from activation of D1-like receptors. On the basis of the effects observed with D2-like antagonist, a subtle contribution of D2-like presynaptic receptors cannot be ruled out.     

Comparison of cone—mediated electroretinograms obtained before and after vincristine chemotherapy

Vincristine has been shown to reduce the amplitude of postreceptoral electroretinographic components in the isolated arterially perfused cat eye. We examined whether a similar effect occurs in vincristine chemotherapy. In the three patients tested, cone—mediated electroretinograms recorded before and after vincristine chemotherapy were not different. This observation is likely to reflect the lower doses of vincristine used therapeutically.     

Electroretinographic abnormalities in multiple sclerosis: possible role for retinal autoantibodies

Background Multiple sclerosis (MS) has been associated with inflammation of the uveal tract, suggesting an immunological link between the uvea and central nervous system (CNS) in this disease. The retina is embryologically derived from the CNS, and it is conceivable that retinal antigens may also be recognized by the immune system in MS. Electroretinographic abnormalities, as well as retinal autoantibodies, have previously been described in MS. We performed this study to further explore the possibility of retinal autoimmunity in MS.Methods Thirty-four patients with clinically definite MS and thirty-seven healthy controls were recruited. All patients and controls had standard electroretinographic (ERG) testing done, as well as a brightflash ERG protocol to isolate rod photoreceptor function. Patient and control sera were analyzed for the presence of antiretinal antibodies using Western blot techniques.Results We found statistically significant differences between MS patients and controls in four ERG parameters. In the MS group, implicit times of the rod-cone b-wave response, cone b-wave response, and rod photoreceptor response were increased. The amplitudes of the photopic oscillatory potentials were reduced in the MS group. Patients with the highest titres of retinal autoantibodies had delayed rod-cone b-wave implicit times and diminished photopic oscillatory potential amplitudes.Conclusions We report ERG evidence of retinal dysfunction in patients with MS. We also report the first use of the brightflash ERG protocol in MS, which demonstrated rod photoreceptor dysfunction. Patients with the highest antiretinal antibody titres had abnormal ERG recordings. Retinal autoimmunity is a possible explanation for these observed ERG abnormalities in MS patients.     

Visual function in hypermetropia

Dark-adapted retinal function was tested electroretinographically and psychophsysically in patients with severe hypermetropia. These patients were first tested in 1982 and were classified into three electroretinographic categories subnormal, normal and supernormal, according to the amplitudes and the b-wave to a-wave relationships of their dark-adapted electroretinographic responses. These patients were invited for a follow-up examination to examine whether the subnormal electroretinogram represented a stationary or a progressive syndrome, to correlate functional vision to the electroretinographic findings and to determine the changes in refraction and electroretinographic responses that might have occurred during an 8-year period. No significant changes were seen in the amplitudes and b-wave to a-wave relationships of the electroretinographic responses. These observations supported the initial electroretinographic classification of the hypermetropic patients and indicated that the patients belonging to the subnormal group were probably characterized by a stationary defect. The psychophysically determined thresholds at different retinal loci (from 30° nasal to 40° temporal) were within the normal range for all the patients regardless of their electroretinographic characteristics. Thus, the abnormal electroretinographic responses of hypermetropic patients probably did not reflect abnormal retinal function but may be accounted for by changes in the electrical resistances of extraretinal tissues relative to that of the retina itself.     

Effects of dopamine receptor blockade on the intensity-response function of ERG b- and d-waves in dark adapted eyes

The effects of dopamine receptor blockade by sulpiride (D₂-class antagonist) and sulpiride plus SCH 23390 (D₁-class antagonist) on the V – log I function of the ERG b- and d-waves were investigated in dark adapted frog eyes. We observed that sulpiride enhanced the amplitude of the suprathreshold b- and d-waves in the lower intensity range, where the responses were mediated by rods, but diminished it in the higher intensity range, where the responses were mediated by cones. A similar effect on the b-, but not d-wave amplitude was seen during the perfusion with sulpiride plus SCH 23390. The d-wave amplitude was enhanced over the whole intensity range with the exception of the highest intensities during the combined D₁ and D₂ receptor blockade. The results obtained indicate that the endogenous dopamine has an overall inhibitory action on the suprathreshold rod-mediated ON and OFF responses, while its action on the cone-mediated responses shows clear ON–OFF asymmetry. It is excitatory upon the ON responses, but inhibitory upon the OFF responses except for those in the highest intensity range. Participation of different types of dopamine receptors (predominantly D₂ for the ON versus D₁ for the OFF response) is probably responsible for this difference.     

Effects of dopamine D(1) receptor blockade on the intensity-response function of ERG b- and d-waves under different conditions of light adaptation

The effect of dopamine D₁ receptor blockade by SCH 23390 on the V-log I function of the ERG b- and d-waves was investigated in dark and light adapted frog eyes. We obtained that the blocker enhanced the amplitude of the b- and d-waves in both conditions of adaptation. The enhancing effect of the blocker was more pronounced on the rod- than cone-dominated responses for the both ERG waves. The absolute sensitivity of the b-wave was not altered, but that of the d-wave was significantly increased. The intensity-response function of the b-wave, but not that of the d-wave, was shifted to the left along the intensity axis. The b-wave V-log I function had steeper slope and narrower dynamic range in both dark and light adapted eyes after the D₁ receptor blockade. The results obtained indicate that the endogenous dopamine, acting through D₁ receptors, does not play a crucial role in the process of retinal adaptation, although it changes in a specific manner the intensity-response function of both the ERG b- and d-waves.     

The electroretinogram (ERG) of a diurnal cone-rich laboratory rodent, the Nile grass rat (Arvicanthis niloticus)

The most widespread models to study blindness, rats and mice, have retinas containing less than 3% cones. The diurnal rodent Arvicanthis niloticus retina has around 35% cones. Using ERG recordings, we studied retina function in this species. Several features differed from that reported in rats and mice: (a) fivefold larger photopic a-wave amplitudes; (b) photopic hill effect in Nile grass rats only; and (c) flicker amplitude plateau between 5 to 35 Hz with fusion beyond 60 Hz in Nile grass rats only. We conclude that A. niloticus might complement rats and mice for studying retinal function and pathologies involving cones.