实验性暗点对多焦视网膜电图的影响

目的：探讨多焦视网膜电图（multifocal electroretinogram,mfERG)的敏感性及有效性。方法：采用刺激屏幕多部位同时遮盖的方法,观察了黑纸及0．3、0．6两种对数单位中性滤光片遮盖后形成的实验性绝对及相对暗点对8例正常眼103个六边形刺激时相应各部位mfERG的影响,并对连续4次检查之间未遮盖部位的mfERG参数进行了分析。结果：六边形被1／2及完全遮盖时,对相应部位mfERG N1、P1波振幅有显著影响,随着透光度的降低,mfERG振幅也逐渐降低。1／3遮盖时,对mfERG各指标无影响。4次重复检查之间,未遮盖部位mfERG各参数无显著差异。结论：mfERG是一种敏感的视觉电生理检查方法,并具有较好的重复性。用103六边形刺激时,mfERG可以检测到大于1／3六边形的暗点。     

Local visual field defects correlate with the multifocal electroretinogram (mfERG) in retinal vascular branch occlusion

BACKGROUND: The value of multifocal electroretinography (mfERG) in the detection of localized retinal dysfunction in vascular branch disease at the posterior pole of the eye is investigated, and mfERG is compared with visual field defects. PATIENTS AND METHODS: 10 eyes of 7 patients were tested, of which 8 eyes had a branch retinal vein occlusion and 2 eyes a branch artery occlusion. First order mfERG's were performed with the VERIS (TM) system, using 61 and 103 hexagons, and visual fields with the OCTOPUS M1 macular program. The number of hexagons with a response density loss (nV/deg (2)) of more than -2.0 standard deviations or of more than - 1.5 StDev, respectively, found in the normal population was compared with the number of disturbed test locations or total sensitivity loss (dB) of M1. RESULTS: Local perimetric defects of various extent correlated well concerning localization and sensitivity loss with mfERG response density loss (nV/deg (2)). The best correlation was the total loss of M1 (dB) versus the number of hexagons out of 103, if the criterion of - 1.5 StDev was applied (p 相似文献   

ISCEV standard for clinical multifocal electroretinography (mfERG) (2011 edition)

The clinical multifocal electroretinogram (mfERG) is an electrophysiological test of local retinal function. With this technique, many local ERG responses are recorded quasi-simultaneously from the cone-driven retina under light-adapted conditions. This document, from the International Society for Clinical Electrophysiology of Vision (ISCEV: ), replaces the ISCEV guidelines for the mfERG published in 2007. Standards for performance of the basic clinical mfERG test with a stimulus array of 61 or 103 hexagons, as well as for reporting the results, are specified.     

Changes in implicit time of the multifocal electroretinogram response following contrast adaptation

PURPOSE: Contrast adaptation, produced by prolonged viewing of high contrast gratings, has been suggested to occur at both retinal and cortical locations within the visual pathway. We sought to investigate the characteristics of retinal contrast adaptation using the multifocal electroretinogram (mfERG). METHODS: Twenty subjects, with a mean age of 27.8 +/- 5.3 years, underwent mfERG testing using VERIS I. The mfERG was measured after 10 minutes of adaptation to 94% contrast, 5 cyc/deg, sinusoidal, vertical gratings and to an equi-luminance blank control. The mfERG stimulus array consisted of 61-scaled hexagons and flickered according to a pseudorandom binary m-sequence (213-1). Changes in amplitude and implicit time of the first-order kernel were analyzed to determine the effect of contrast adaptation on retinal responses. RESULTS: Adaptation to the vertical grating pattern produced a 2.5 ms increase in implicit time, and the response delay was greatest in the more peripheral parts of the retina (7.6 degrees to 30 degrees ). Contrast adaptation did not produce statistically significant changes to the amplitude of the mfERG waveform. CONCLUSIONS: Contrast adaptation produced by prolonged viewing of high contrast gratings had a significant effect on retinal responses. It has been suggested that contrast adaptation may play a role in the development of nearwork induced myopia; further work investigating retinal contrast adaptation in myopic individuals may be of interest.     

Assessment of retinal function in patients with HIV without infectious retinitis by multifocal electroretinogram and automated perimetry

PURPOSE: To determine if multifocal electroretinogram (mfERG) testing shows abnormalities that correspond to perimetric defects in HIV positive patients without infectious retinitis. METHODS: We studied three groups of patients: HIV negative controls, HIV high CD4 nadir patients (lowest CD4 T cell count is over 100) and low CD4 nadir patients (below 100 for over 6 months). Twenty-six HIV positive eyes and 16 HIV negative control eyes were studied by mfERG. A subset of 10 eyes also underwent computerized perimetry for comparison. We analyzed mfERG by hexagons as well as by quadrants and rings. RESULTS: Of 103 hexagon locations there was no significant difference in the amplitudes P1 and N1 (nV/degree) between the three studied groups (p>0.05), similarly, the latencies were not different (p>0.05). All eyes with significant visual field defects at the 0.01 and 0.005 level (Humphrey pattern deviation; 24-2) were compared to mfERG amplitudes and latencies at those locations-there were no corresponding defects in mfERG data (p>0.2). CONCLUSION: In the era of HAART there are still demonstrable visual field defects and other evidence of damage to the retinal nerve fiber layer in HIV patients. Our mfERG studies show that the damage appears to affect the inner retina, the outer retina is spared. Further studies of inner retinal structure and function are indicated to elucidate this process.     

Evaluation of focal retinal function using multifocal electroretinography in patients with X-linked retinoschisis

Objective: To evaluate focal retinal function in patients presenting with features of X-linked retinoschisis (XLRS), with the use of multifocal electroretinography (mfERG).Design: Consecutive observational case-control study.Participants: Eighteen eyes of 9 patients who presented to the retina clinic of Sankara Nethralaya from 2005 to 2008.Methods: XLRS was diagnosed clinically and corroborated with full-field electroretinogram (ffERG), mfERG, and optical coherence tomography. ffERG and mfERG recordings were done with VERIS 5.2.2X according to International Society for Clinical Electrophysiology of Vision standards. The mfERG stimulus consisted of 103 hexagons flickered at a 75 Hz frame rate, subtended 35° horizontally and 31° vertically at a viewing distance of 53 cm. The amplitudes and implicit times of ffERG and first-order kernels of mfERG were analyzed and compared with those of the controls.Results: P1 and N1 amplitudes were reduced and P1 and N1 implicit times were prolonged significantly in patients with XLRS, compared with controls.Conclusions: mfERG helps estimate focal retinal function in patients with XLRS.     

Multifocal electroretinography and optical coherence tomography in two patients with solar retinopathy

PURPOSE: Clinical investigation of central retinal dysfunction in two cases of solar retinopathy. METHODS: Two patients were examined for best corrected visual acuity (VA), fundus inspection, visual fields, multifocal electroretinography (mfERG) with a stimulus pattern of 241 hexagons and, at follow-up, also with optical coherence tomography (OCT). RESULTS: At the initial examination, mfERG revealed central retinal dysfunction, which had improved by the time of follow-up. In Case 1, a foveal oedema regressed over time, although VA remained slightly reduced. In Case 2, OCT showed spots of increased reflectivity corresponding to the patient's symptoms. CONCLUSION: Central retinal dysfunction due to solar retinopathy may improve over time. However, structural and functional changes may persist. This report illustrates that mfERG and OCT are useful tools for objective documentation of the pathology in solar retinopathy.     

Multifocal ERG findings in carriers of X-linked retinoschisis

Purpose To determine whether retinal dysfunction in obligate carriers of X-linked retinoschisis (XLRS) could be observed in local electroretinographic responses obtained with the multifocal electroretinogram (mfERG). Methods Nine obligate carriers of XLRS (mean age, 46.2 years) were examined for the study. Examination of each carrier included an ocular examination and mfERG testing. For the mfERG, we used a 103-scaled hexagonal stimulus array that subtended a retinal area of approximately 40° in diameter. The amplitudes and implicit times in each location for the mfERG were compared with the corresponding values determined for a group of 34 normally-sighted, age-similar control subjects. Results Mapping of 103 local electroretinographic response amplitudes and implicit times within a central 40° area with the mfERG showed regions of reduced mfERG amplitudes and delayed implicit times in two of nine carriers. Conclusions The mfERG demonstrated areas of retinal dysfunction in two carriers of XLRS. When present, retinal dysfunction was evident in the presence of a normal-appearing fundus. Multifocal ERG testing can be useful for identifying some carriers of XLRS.     

Regional variations in local contributions to the primate photopic flash ERG: revealed using the slow-sequence mfERG

PURPOSE: To determine the variations with eccentricity of the primate photopic ERG and to separate contributions by different retinal cells by using intravitreal pharmacologic agents. METHODS: Slow-sequence multifocal (mf)ERGs were obtained from 19 anesthetized adult rhesus monkeys and 5 normal human subjects. Recordings in monkeys were obtained before and after injections of tetrodotoxin citrate (TTX) to block sodium-dependent spiking; TTX+N-methyl-D-aspartic acid (NMDA)+picrotoxin (PTX) or gamma-aminobutyric acid (GABA) to block all inner retinal activity; L-2 amino-4-phosphonobutyric acid (APB) to block the On-pathway; and cis-2, 3 piperidine dicarboxylic acid (PDA) to block the Off-pathway and the otherwise unblocked inner retinal activity. The stimulus consisted of 103 equal-sized hexagons within 17 degrees of the fovea; every 200 ms (15 frames), each hexagon had a 50% chance of remaining at 20 cd/m(2) or increasing briefly to 4.7 cd-s/m(2). Oscillatory potentials (OPs; 90-300 Hz) were extracted. RESULTS: The slow-sequence mfERG summed over the stimulated area looked similar to a standard photopic, full-field ERG, with a- and b-waves and OPs. OPs in the foveal and temporal retina were larger than in the nasal retina. This nasotemporal asymmetry was removed by TTX, and the OPs were eliminated, either by blocking inner retina activity or by blocking the On-pathway. The summed mfERG waveform, including OPs, was shaped mainly by the more peripheral retinal regions. The foveal b-wave peak occurred about 5 to 6 ms later than in the periphery, with the depolarizing peak of the On-pathway/bipolar contribution occurring earlier than the depolarizing peak of the Off contribution at all eccentricities. The a-wave was composed of a small photoreceptor contribution and postreceptoral portion originating from hyperpolarizing neurons. CONCLUSIONS: The variations in the primate photopic ERG with eccentricity are due to spike-driven oscillatory activity that is more prominent in central and temporal retina than in nasal retina and to the slower timing of all responses in the central, compared with the peripheral, retina. The full-field, photopic ERG most closely resembles the mfERG responses to stimulation of peripheral regions.     

A comparison of multifocal ERG and frequency domain OCT changes in patients with abnormalities of the retina

To compare the ability of the multifocal electroretinogram (mfERG) and frequency domain optical coherence tomography (fdOCT) to detect retinal abnormalities. A total of 198 eyes (100 patients) were referred by neuro-ophthalmologists to rule out a retinal etiology of visual impairment. All patients were evaluated with static automated perimetry (SAP) (Humphrey Visual Field Analyzer; Zeiss Meditec), mfERG (Veris, EDI) and fdOCT (3D-OCT 1000, Topcon). The mfERG was performed with 103 scaled hexagons and procedures conforming to ISCEV standards (Hood DC et al. (2008) Doc Ophthalmol 116(1):1–11). The fdOCT imaging included horizontal and vertical line scans through the fovea. Local mfERG and fdOCT abnormalities were compared to local regions of visual field sensitivity loss measured with SAP and categorized as normal/inconclusive or abnormal. 146 eyes were categorized as normal retina on both fdOCT and mfERG. The retina of 52 eyes (36 patients) was categorized as abnormal based upon mfERG and/or fdOCT. Of this group, 25 eyes (20 patients) were abnormal on both tests. However, 20 eyes (13 patients) were abnormal on mfERG, while the fdOCT was normal/inconclusive; and 7 eyes (7 patients) had normal or inconclusive mfERG, but abnormal fdOCT. Considerable disagreement exists between these two methods for detection of retinal abnormalities. The mfERG tends to miss small local abnormalities that are detectable on the fdOCT. On the other hand, the fdOCT can appear normal in the face of clearly abnormal mfERG and SAP results. While improved imaging and analysis may show fdOCT abnormalities in some cases, in others early damage may not appear on structural tests.     

The effects of pupil size on the multifocal electroretinogram

This is an investigation of the effect of changing the pupil diameter on the P1 amplitude and latency of the multifocal electroretinogram (mfERG). MfERGs were recorded using a custom built wide field electrophysiological system. An array of 61 empirically scaled hexagons was used to stimulate the visual field. The duration of overall recording period was 8 min, segmented into 16 intervals each lasting 30 s. A combination of mydriatics and miotics were used to pharmacologically alter the pupil size and diameters between 1 and 10 mm were measured. There was a reduction in mfERG P1 amplitude in some cases greater than 50 (mfERG P1 amplitude 53 nV at 8 mm to 25 nV at 1 mm), with a change in pupil diameter of 7 mm. The mfERG P1 latency increased in some cases by as much as 8 ms in the central 40° (mfERG P1 latency 39 ms at 8 mm to 47 ms at 1 mm). These results suggest that pupil size has significant effects on mfERG P1 amplitude and latency.     

Multifocal electroretinography in eyes with reticular pseudodrusen

Purpose. The aim of our study was to evaluate the impact of reticular pseudodrusen (RPD) on retinal function by multifocal electroretinography (mfERG), and combined simultaneous confocal scanning laser ophthalmoscopy (cSLO) and spectral-domain optical coherence tomography (SD-OCT). Methods. We included 19 eyes of 15 patients with RPD in the posterior pole and no other phenotypic retinal alteration were included (7 females and 8 males, age 77.2 ± 5.1 years) as well as 24 eyes of 17 healthy control subjects (7 females and 10 males, age 73.2 ± 5.9 years). All patients underwent fundus photography, SD-OCT, fluorescence angiography (FA), fundus autofluorescence, and near-infrared reflectance cSLO. mfERG measurements were performed by stimulating the retina by a field of 103 hexagons covering an area of approximately 30°. Amplitudes and latencies of focal retinal responses obtained at affected and nonaffected sites of RPD eyes and retinal responses of healthy control subjects were compared. Results. In all included study eyes, RPD stages 1-3 could be demonstrated clearly in SD-OCT, FA, and cSLO. The mean amplitudes measured in the areas affected by RPD were 12.5 to 53.1 nV/deg(2) (control group 19.4-50.1 nV/deg(2)). The mean latencies were 33.2 to 41.3 ms (control group 33.6-39.7 ms). mfERG amplitudes and latencies of retinal areas affected by RPD were not altered significantly when compared to corresponding nonaffected areas. Conclusions. mfERG measurements did not show a definite influence on electrophysiologic activity in retinal areas affected exclusively with RPD.     

Multifocal VEP (mfVEP) reveals abnormal neuronal delays in diabetes

This pilot study examined the diagnostic role of multifocal visually evoked potentials (mfVEP) in a small number of patients with diabetes. mfVEP, mfERG, and fundus photographs of both eyes of five patients with diabetes, three with nonproliferative diabetic retinopathy (NPDR) and two without NPDR were examined. Thirteen control subjects were also examined. Eighteen zones were constructed from the 60-element mfVEP stimulus array. mfVEP implicit time (IT) and amplitude (SNR) differences were tested between subject groups. We also examined whether there was a difference in function for patches with and without retinopathy in the NPDR group. Lastly, we compared mfVEP and mfERG results in the same patients. We found significant mfVEP IT differences between controls and all patients with diabetes, controls and diabetics without retinopathy, and between controls and diabetics with retinopathy. The subject groups did not differ significantly in terms of SNR. In the retinopathy group, ITs from zones with retinopathy were significantly longer than ITs from zones without retinopathy (P = 0.016). mfERG IT was more frequently abnormal than mfVEP IT. In addition, mfERG hexagons were twice as likely to be abnormal if the corresponding mfVEP zone was abnormal (P < 0.05). mfVEP implicit times are significantly delayed in patients with diabetes even when there is no retinopathy. These cortical response results are similar, albeit considerably less abnormal, than those previously reported for retinal (mfERG) responses in patients with diabetes. A correlation exists between the location of abnormal mfERG hexagons and abnormal mfVEP zones.     

正常人多焦视网膜电图一、二阶函数核反应特征分析

目的:比较正常人多焦视网膜电图(multifocalelectroretinogram,mfERG)一、二阶函数核的波形及视网膜分布特点。方法:使用VERISScienceTM4.0系统,采用对比度为96%的103个六边形刺激模式,记录了17只正常人眼mfERG。结果:与一阶函数核相比较,mfERG二阶函数核波形较复杂、子波较多。其中一片反应一般有三个正向及负向波,而二片反应有四个正向及负向波。除潜伏期外,二阶函数核与一阶函数核振幅反应的视网膜分布特征基本一致,以中心凹处振幅密度反应最大,随离心度加大振幅逐渐降低;上方视网膜反应大于下方视网膜,颞侧视网膜反应大于鼻侧视网膜。但总能量明显小于一阶函数核。结论:正常人mfERG二阶函数核的视网膜分布特点与一阶函数核基本一致,二阶函数核对于某些疾病的诊断是否具有特异性,有待于进一步研究。     

Retinal dysfunction in carriers of bardet-biedl syndrome

PURPOSE: To determine whether retinal dysfunction in obligate carriers of the Bardet-Biedl syndrome (BBS) could be observed in local electroretinographic responses obtained with the multifocal electroretinogram (mfERG). METHODS: Six obligate carriers of the BBS were examined for the study. Examination of each carrier included an ocular examination and mfERG testing of one eye. For the mfERG, we used a 103-scaled hexagonal stimulus array that subtended a retinal area of approximately 40 degrees in diameter. The amplitudes and implicit times in each location for the mfERG were compared with the corresponding values determined for a group of 34 normally sighted, age-similar control subjects. RESULTS: Mapping of 103 local electroretinographic response amplitudes within a central 40 degrees area with the mfERG showed regions of reduced mfERG amplitudes in three of six carriers. Implicit time measurements in the 6 carriers were all normal except for those locations associated with abnormal amplitude reductions in 3 of the carriers. When present, retinal dysfunction was evident in the presence of a normal-appearing fundus. CONCLUSIONS: Multifocal ERG testing can demonstrate areas of retinal dysfunction in carriers of the BBS. This test may therefore be useful for identifying some heterozygous carriers of this disease.     

Lateral spread of adaptation as measured with the multifocal electroretinogram

We examined whether lateral spread of adaptation can be observed in the electroretinogram in humans. Specifically, we tested whether the luminance level of a surrounding, nonmodulated annulus affects the multifocal electroretinogram (ERG) response of a modulated central area. Multifocal electroretinograms were recorded in response to an array of 37 unscaled hexagons subtending a retinal area of 38 deg x 35 deg. Responses were recorded in six control subjects. In the first series of experiments, only the center hexagon was modulated, while the surrounding 36 hexagons were held constant at either 0.45, 172, or 340 cd/m2. In a subsequent series of control experiments, modulation depth of the center hexagon was varied and the proximity of the surrounding hexagon systematically altered. For the center-modulated condition, response amplitude and implicit time for the first-order kernel response significantly decreased as a function of increasing surround luminance. Control experiments demonstrated that the effect of the surround illumination was not due to scattered light but was influenced by the proximity of the surrounding annulus. These results demonstrate that lateral adaptation influences can be measured using the multifocal ERG.     

Transitions of multifocal electroretinography following combined intravitreal bevacizumab and photodynamic therapy for polypoidal choroidal vasculopathy

Multifocal ERG ring ratios provide a sensitive and objective method to detect ocular toxicity in patients taking hydroxychloroquine (Plaquenil). In order to measure ring ratios, the average mfERG amplitude was calculated for each of five concentric rings of a 61-hexagon mfERG. The age-corrected amplitude of the central hexagon (R₁) and the ratios of R₁ to each of the successive rings (R₁/R₂, R₁/R₃, etc.) were then computed. Normative values for ring ratios were established from a population of 67 normal controls. In the study population, a ring was considered abnormal if it was above the 99% confidence limits for the normal population. The technique was evaluated on 131 eyes of 62 patients taking Plaquenil for a variety of conditions including rheumatoid arthritis, systemic lupus erythematosus, and Sjögren’s syndrome. Patients who had taken Plaquenil for an extended period showed a higher incidence of retinal toxicity, regardless of the condition for which they were taking the drug. Among patients who had taken a cumulative dose of less than 1,250 g, 7 of 67 eyes (10%) showed a characteristic mfERG defect, while in patients with a cumulative dosage of 1,250 g or more, 26 of 64 eyes (41%) showed one of these defects. In at least one patient, the technique was able to detect the early onset of Plaquenil toxicity followed by reversal of the toxic effects after the medication was discontinued. It appears appropriate to recommend that mfERG testing be done on all patients on Plaquenil therapy.     

Evaluation of inner retinal function in myopia using oscillatory potentials of the multifocal electroretinogram

PURPOSE: Oscillatory potentials have been suggested to arise from the inner retina at the level of amacrine cells and inner plexiform layer and they are thought to provide a non-invasive assessment of inner retinal function. We sought to investigate the response dynamics of the inner retina of adult emmetropes and myopes by analysing the oscillatory potentials of the multifocal electroretinogram (mfERG) in these groups. METHODS: Eleven emmetropes and 18 myopes underwent mfERG testing using VERIS 5.1.5X. Myopes were further separated based on whether their myopia was stable (n=9) or progressing (n=9). Oscillatory potentials were recorded using a modified mfERG stimulation technique, the slow flash paradigm, and they were extracted using band-pass filtering from 100 to 300 Hz. The slow flash mfERG stimulus array consisted of 103-scaled hexagons and flickered according to a pseudorandom binary m-sequence (2(13)-1). Amplitudes and implicit times of the first-order oscillatory potentials were analysed. RESULTS: There were significant differences in the implicit time of the oscillatory potentials of the emmetropes, stable myopes and progressing myopes (F(2,25)=3.663, p=0.043). Progressing myopes had significantly shorter implicit times compared to emmetropes (p=0.026 by 1.0-4.7 ms) and stable myopes (p=0.043 by 0.8-1.3 ms), whereas implicit times of stable myopes and emmetropes were similar. There were no statistically significant differences in amplitude of the oscillatory potentials between the groups (F(2,25)=0.890, p=0.426). CONCLUSIONS: Significant differences in multifocal oscillatory potentials between stable and progressing myopes were found. This finding is further evidence of an inner retinal involvement in human myopia progression and may suggest an underlying alteration to dopaminergic or GABAergic retinal systems.     

Effects of stimulus blocking, light scattering, and distortion on multifocal electroretinogram

PURPOSE: To investigate how the multifocal electroretinogram (ERG) is altered in conditions of blocking, light scattering, or distortion of the stimulus that are seen in ocular pathologies. METHODS: A central 40 degree-diameter stimulus pattern consisting of 61 hexagons was presented on a cathode ray tube monitor at a rate of 75 Hz according to the pseudo-random binary M sequence by the Veris computer program. Localized responses corresponding to each hexagon and ERG topographies were displayed on the computer screen. Central scotoma was simulated by blocking the central area of the stimulus, visual field constriction by blocking the outer area of the stimulus, mild cataract by using acrylic filters that caused light scatter, and epiretinal membrane by using a wavy plastic plate that produced metamorphopsia. RESULTS: The responses from the blocked area were nonrecordable whether blockage was central or peripheral; responses from the adjacent unblocked area had a larger amplitude when large areas of the stimulus were blocked. The light scatter that decreased vision from 20/20 to 20/70 did not significantly decrease response amplitudes. Responses from areas in which the stimulus pattern was distorted were minimally affected. CONCLUSIONS: The results show that the system records local ERGs from the macula and outside the macula. It can detect the area where the stimulus is blocked. Moderate light scattering and distortion do not cause loss of local ERG characteristics.