Changes in the s-Wave of Multifocal Electroretinograms in Eyes with Primary Open-Angle Glaucoma

Purpose To determine whether the s-wave is present in the multifocal electroretinogram (mfERG) and whether it is altered in eyes with primary open-angle glaucoma (POAG).Methods A Visual Evoked Response Imaging System was used to record mfERGs from 15 eyes of 15 normal adults, as control eyes, and from 15 eyes of 15 patients with POAG. The stimulus consisted of 37 hexagonal stimulating elements with luminances of 200cd/m² (white), 66.6cd/m² (gray), and 4cd/m² (black). The white or black element was presented at five different base periods (bpds) from 13.3 to 213.3ms according to a binary m-sequence. In the intervals between the white and black (or white) elements, gray elements were inserted at 75Hz. The changes in the amplitude and implicit time of the s-wave of the all-trace waveform of the first-order kernel of the mfERG were compared with the mean deviation (MD) of retinal sensitivity in the whole visual field measured with a Humphrey Field Analyzer.Results The s-wave was present as a positive wavelet on the descending limb of the first-order kernel response of the mfERGs of all eyes with POAG. The s-wave amplitude increased with prolongation of the bpd, as occurs in normal eyes. The mean amplitudes of the s-waves at bpds of 53.3 and 106.7ms were significantly smaller in the eyes with POAG than in the control eyes. The correlation between the s-wave amplitude and the severity of disturbance in the entire visual field indicated by the MD was not significant in eyes with POAG.Conclusions The characteristics of the s-wave in glaucomatous eyes were the same as those in the control eyes, but the amplitude of the s-waves in POAG eyes was significantly lower than that in the control eyes. This suggests that ganglion cells may be involved in the development of the s-wave. When comparing the s-wave with static perimetry, more local responses of the s-wave and more local retinal sensitivity in the static perimetry will be appropriate. Jpn J Ophthalmol 2004;48:208–214 © Japanese Ophthalmological Society 2004     

The effect of contrast and luminance on mfERG responses in a monkey model of glaucoma

PURPOSE: To evaluate the effect of contrast and luminance attenuation on the multifocal electroretinogram (mfERG) responses of normal and glaucomatous eyes of cynomolgus monkeys. METHODS: Nine adult male cynomolgus monkeys with unilateral experimentally induced glaucoma were used. Hypertension-induced damage was confirmed by tomography of the optic disc. mfERGs were recorded with five different stimulus contrasts and/or luminance settings. The first-order and the first slice of second-order responses were analyzed. RESULTS: Waveforms of normal and glaucomatous eyes differed in shape and amplitude. Second-order responses contributed to first-order responses of the signals in the normal eyes, but made a negligible contribution to the signals in the glaucomatous eyes. Contrast and luminance attenuation affected both first- and second-order responses. The differences between signals in normal and glaucomatous eyes were sufficiently large for an unsupervised clustering algorithm to achieve accurate segregation. CONCLUSIONS: The observations in this study indicate that outer and inner retinal generators participate in first-order mfERG responses and that both inner and outer retinal contributors respond to contrast and luminance changes in stimulus. The hypertension-induced changes in the mfERG furthermore suggest damage to both inner and outer retina.     

The s-Wave of the Multifocal Electroretinogram in Cats

Purpose To characterize the s-wave of the multifocal electroretinogram (mfERG) in cats, and to determine the contribution of the inner retina to the s-wave by examining the effects of tetrodotoxin (TTX) and N-methyl d-aspartate (NMDA) injected into the vitreous cavity. Methods mfERGs were recorded from 15 eyes of 15 male cats under general anesthesia. The stimulus consisted of 37 elements, and the luminance of the bright and the black elements were 200 and 4 cd/m², respectively. The stimuli were presented in a pseudorandom binary m-sequence at six different base periods (bpds) from 13.3 to 426.7 ms. Fifty microliters of 7.0 μM TTX followed by 50 μl of 4.0 mM NMDA were injected into the vitreous cavity. Results The shape of the mfERGs in the cats resembled that in humans. The s-wave appeared on the descending limb of P1, as seen in human mfERGs, in 11 eyes, and the s-wave amplitude increased significantly as the bpd was increased. TTX and NMDA resulted in the disappearance of the s-wave at all bpds, while the amplitude of P1 remained unchanged. Conclusions The s-wave is present in the mfERG in the cat, and its loss following injections of TTX and NMDA supports the view that the s-wave reflects the function of the ganglion cells and their axons. Jpn J Ophthalmol 2006;50:432–437 ? Japanese Ophthalmological Society 2006     

Visual evoked potentials elicited by pseudorandom stimulation from patients with macular degeneration

PURPOSE: To investigate the effect of a central scotoma on the amplitude, implicit time (IT), and temporal frequency characteristics (TFC) of the visual evoked potentials (VEPs) elicited by a pseudorandom binary sequence (PRBS) stimulus in age-related macular degeneration (AMD) patients. METHODS: Twenty-six patients with AMD, 17 eyes with visual acuity of less than 20/100, and 9 eyes with visual acuity between 20/70 and 20/25, were examined. Nine eyes of age-matched healthy volunteers served as controls. To elicit the PRBS-VEPs, one eye was stimulated with a PRBS stimulus. The first-order kernel was calculated from a cross-correlation between the PRBS and the VEPs. The Fourier transformed first-order kernel was used as the TFC of the visual system. RESULTS: The mean IT of P2 (second positive peak) of the first-order kernel was significantly delayed (t-test, P <.05), and the P2-N2 (peak-to-peak of P2 and second negative peak N2) amplitude was significantly reduced (t-test, P <.01) in eyes with AMD. A depression of the TFC values in the 6-18 Hz band was prominent in patients with AMD (t-test, P <.01). CONCLUSION: PRBS-VEPs demonstrated a prolonged IT and reduced amplitude of the first-order kernel, and reduced TFC with a reduction of visual acuity in patients with macular degeneration.     

屈光不正性弱视患者多焦视网膜电图一阶反应P1波特征分析

目的 研究屈光参差性弱视患者mfERG一阶反应P1波特征,探讨mfERG在弱视诊断中的应用价值.方法 采用罗兰RETIscan型电生理仪检测一组(15例)屈光参差性弱视患者mfERG,选择一阶反应第一环P1波为指标,计算其平均振幅密度(nV·deg-2)及潜伏期(ms),采用配对t检验比较弱视眼与对侧健眼的统计学差异.结果 弱视眼P1波平均振幅密度为(164.7±73.1)nV·deg-2,对侧健眼为(227.0±61.3)nV·deg-2,差异有统计学意义(t=2.554,P=0.016);弱视眼P1波平均潜伏期为(30.3±4.3)ms,对侧健眼为(34.4±3.2)ms,差异有统计学意义(t=2.92,P=0.007).结论 屈光参差性弱视患者弱视眼mtERG一阶反应第一环P1波有明显改变,提示弱视眼存在视网膜开-双极细胞功能及视觉信息传导异常,mfERG有可能用作弱视的诊断的客观指标.     

Shift of temporal responsivity curve of pattern reversal visually evoked potentials to lower frequencies in patients after recovery from optic neuritis

Purpose: To investigate the responsivity of the visual system to pattern reversal stimuli of different reversal rates in optic neuritis patients after a full recovery of visual acuity. Methods: Thirty eyes with optic neuritis and 30 eyes of age‐matched normal controls were studied. Steady‐state pattern reversal visually evoked potentials (P‐VEPs) were recorded using reversal rates of 2, 10, 20 and 30 Hz. The relationship between the amplitudes of the P‐VEPs and reversal rate was analysed. The temporal responsivity curves of the two groups were compared. Results: The means ± standard deviations (SDs) of the P‐VEP amplitudes in the normal controls were 7.08 ± 2.97, 8.60 ± 2.37, 4.69 ± 1.99 and 2.11 ± 1.24 μV at reversal rates of 2, 10, 20 and 30 Hz, respectively. The comparable amplitudes from the recovered optic neuritis patients were 8.01 ± 2.45, 6.57 ± 2.54, 2.73 ± 1.76 and 0.94 ± 1.27 μV. The mean amplitude of the P‐VEPs elicited at a reversal rate of 2 Hz was not significantly different from that of normal controls. However, the amplitudes of the P‐VEPs at reversal rates of 10, 20 and 30 Hz were significantly smaller in the recovered optic neuritis patients than in the controls. In addition, the average maximum amplitude of the P‐VEPs was obtained at 10 Hz in normal subjects and at 2 Hz in the recovered optic neuritis patients. Conclusion: These results indicate that the peak of the temporal tuning curve of the P‐VEP shifts to lower frequencies in recovered optic neuritis eyes, and that the reduced amplitudes at higher frequencies seem to be characteristic of the visual system of patients with recovered optic neuritis.     

Multifocal ERG findings in complete type congenital stationary night blindness

PURPOSE. To study the multifocal electroretinogram (mfERG) in patients with the complete type of congenital stationary night blindness (cCSNB), which is thought to be due to a defect in neurotransmission from the photoreceptors to the ON-bipolar cells. METHODS. mfERGs were recorded with the VERIS recording system from four patients with cCSNB, none of whom had nystagmus. The stimulus array consisted of 61 hexagons, and the total recording time was approximately 4 minutes. The amplitudes and implicit times of the first- and second-order kernels of the local responses were compared with those from 20 myopic controls. Waveforms of the summed response from all locations were also compared between the two groups. RESULTS. The first-order kernels of the mfERGs of cCSNB patients had normal amplitudes but delayed implicit times for nearly the whole field tested. The second-order kernel was severely attenuated in amplitude in cCSNB patients. The ratios of the second- to first-order kernel amplitudes were significantly reduced in cCSNB and clearly separated the cCSNB group from the control group without any overlap of the values. CONCLUSIONS. The second-order kernel, which is involved in adaptative mechanism of the retina to repeated flashes, is selectively reduced in cCSNB. The delay of the implicit times of the first-order kernel in patients with cCSNB may be related to the severe amplitude reduction of the second-order kernel.     

Different transitions of multifocal electroretinogram recordings between patients with age-related macular degeneration and polypoidal choroidal vasculopathy after photodynamic therapy

AIM: To compare and evaluate the transitions in retinal function after photodynamic therapy (PDT) between age-related macular degeneration (AMD) and polypoidal choroidal vasculopathy (PCV) using multifocal electroretinograms (mfERGs). METHODS: 10 eyes with choroidal neovascularisation (CNV) secondary to AMD and 11 eyes with CNV secondary to PCV were included in the study. mfERGs were recorded before PDT, and 1 week and 3 months after PDT. mfERG recordings were acquired by a Veris system (V.3.1.3) using a 103 hexagon stimulus. The first-order kernel was used to calculate amplitudes and latencies. Mean amplitudes and latencies from two central rings rated 0-4 degrees of visual angle were analysed and compared with each disease. RESULTS: In AMD, the mean first negative peak (N1) amplitudes tended to decrease, and the mean first positive peak (N1P1) amplitudes reduced to significant levels (p = 0.047) 1 week after PDT. 3 months after PDT, there were no significant differences in the mean N1 and N1P1 amplitudes compared with pre-PDT values. In PCV, there were no significant changes in the mean N1 and N1P1 amplitudes 1 week after treatment. However, 3 months after PDT, mean amplitudes showed significant increases in N1 (p = 0.008) and N1P1 (p = 0.006) amplitudes compared with pre-PDT values. CONCLUSIONS: mfERG recording transitions are different between patients with AMD and those with PCV. In patients with AMD, these results may show transient impairments in retinal function 1 week after PDT, but in those with PCV, the efficacy of PDT is superior to the impairment after PDT.     

LED刺激器多焦视网膜电图一阶和二阶反应波形研究

目的研究二极管发光器(LED)的多焦视网膜电图(mfERG)的一阶及二阶波形特点。设计前瞻性、非对照干预研究。研究对象18例(18眼)正常人。方法18眼随机分为两组分别作阴极射线管(CRT)及LED的mfERG检查。LED刺激时间分为1/10(1．7ms)、3/10(5ms)、5/10(8．3ms)、7/10(11．7ms)、10/10(16．7ms)5种。主要指标mfERG总和反应波形特点,P1、N1及N2波形态、振幅密度及潜伏期。结果CRT及LED刺激器mfERG一阶反应波形基本相似；CRT及LED刺激器的mfERG二阶反应波形不同,前者的P1波呈尖峰状,后者的P1波较宽,呈方形,且伴有一个较深的N2波。随着刺激时间的延长,LED刺激器的mfERG一阶及二阶反应中的P1波及N1波的振幅密度增加,潜伏期延长。结论CRT及LED刺激器的mfERG一阶反应波形基本相同,但LED的二阶反应波形更丰富,其可能包涵了更多视网膜内层信息。(眼科,2006,15：351-355)     

Multifocal electroretinograms in X-linked retinoschisis

PURPOSE: To study local retinal cone function in patients with X-linked retinoschisis (XLRS) by multifocal ERGs (mfERGs). METHODS: mfERGs were recorded from seven eyes of seven patients with XLRS (mean age +/- SD, 22.1 +/- 3.2 years; range, 18 to 25 years). Five eyes had microcystic changes in the macula and two eyes had nonspecific macular degeneration. Two eyes had peripheral retinoschisis, and some of the stimuli fell on this area. The stimulus array consisted of 103 hexagons and the total recording time was set at approximately 4 minutes. The amplitudes and implicit times of both focal and summed responses for the first- and second-order kernels were analyzed. RESULTS: The amplitudes of the first-order kernel were markedly reduced in the central retina in all eyes. A large variation was observed in the amplitudes outside the fovea. The amplitudes of the focal cone ERGs at the peripheral retinoschisis did not differ from those recorded from adjacent retinal loci without the retinoschisis. The implicit times of the first-order kernel were significantly delayed, and the amplitudes of the second-order kernels were more affected than the first-order kernels across the whole field in all XLRS eyes. CONCLUSIONS: The cone-mediated retinal responses were more impaired in the central than peripheral retina in eyes with XLRS. Delayed implicit times of the first-order kernel and reduced second-order kernel across the whole testing field in all XLRS eyes suggest that there is widespread cone-system dysfunction in XLRS.     

Inner retinal contributions to the multifocal electroretinogram: patients with Leber's hereditary optic neuropathy (LHON)

In this study we examine the multifocal electroretinogram (mfERG) recorded from patients suffering from Leber's hereditary optic neuropathy (LHON), a degeneration of the ganglion cell and nerve fibre layers of the retina. We compared the mfERGs recorded from 11 patients with LHON, to those from 11 control subjects. The pattern ERG (PERG) was additionally performed with 9 of the patients. MfERGs were recorded and analysed using the VERIS^TM 3.01 system with a stimulus of 103 equal-sized hexagons. For analysis, hexagons were grouped according to distance from the optic nerve head (ONH) and according to distance from the fovea. Two significant differences were found between the waveforms of the two groups: In the first order kernel, the control group showed a component around 34 ms that decreased with distance from the ONH. This component was reduced in the LHON group of subjects. In the second order (first slice) kernel, the patient group was missing features that decrease with distance from the fovea in the control group. PERG amplitudes showed a significant correlation with the amplitude of the second order mfERG kernel. The results show that the damage to ganglion cells and nerve fibres caused by LHON can be detected in mfERG recordings and indicate that activity from the inner retina can contribute significantly to first and second order waveforms.     

Stray light-induced multifocal electroretinograms

PURPOSE: To evaluate the characteristics of stray light-induced response in multifocal ERG (mfERG) elicited by the stimulus falling on the disc. METHODS: A patient with an enlarged optic disc (4 x 4 disc diameters of disc of normal fellow eye) and four normal volunteers served as subjects. The mfERGs elicited by different stimulus intensities (0.67-4.67 cd-sec/m(2)) were recorded from the patient, and the mfERGs obtained with stimuli on the enlarged optic disc. For comparison, full-field pseudorandom ERGs (ffprERGs) were also recorded in all subjects. The first-order kernels (K1) and the second-order kernels (K2.1) were analyzed. RESULTS: A small and delayed K1 was recorded on the enlarged disc, but K2.1 was flat on the disc at all intensities. The implicit time of K1 at lower intensities was longer than at higher intensities. ffprERGs at very low intensities in the patient and normal subjects were similar to the mfERG on the disc (delayed K1 associated with flat K2.1). CONCLUSIONS: The responses elicited by stimulating the disc were delayed in K1 and flat in K2.1. Because similar ffprERGs were observed at very low intensities, it is likely that an optic disc with high reflectance scattered the stimulus light to create a weak full-field stimulus. Thus, care must be taken when focal lesions are investigated with mfERGs.     

Visual evoked potentials elicited by pseudorandom stimulation in macular degeneration]

PURPOSE: To investigate the effect of a central scotoma on the amplitude, latency, and temporal frequency characteristics(TFCs) of the visual evoked potentials(VEPs) elicited by a pseudorandom binary stimulus(PRBS). METHOD: Patients with age-related macular degeneration(AMD) were selected, and VEPs were recorded from 26 eyes with AMD(17 eyes with visual acuity of less than 0.2, and 9 eyes with visual acuity between 0.3 and 0.9). Nine eyes of age-matched normal volunteers served as controls. To acquire the PRBS-VEPs, one eye was stimulated with a PRBS stimulus. The first order kernel was calculated from a cross correlation between PRBS and VEPs. The Fourier transformed first-order kernel was used as the TFC of the VEPs. RESULTS: The P2 latency of the first order kernels was delayed(p < 0.05), and the P2-N2 amplitude was reduced(p < 0.01) in AMD. A depression of the TFC values in the 6-18 Hz band was prominent in the patients with AMD(p < 0.01). CONCLUSION: The TFC, were strongly correlated with the visual acuity of patients with macular degeneration.     

Multifocal electroretinogram delays predict sites of subsequent diabetic retinopathy

PURPOSE: To examine the potential of abnormal mfERGs to predict the development of diabetic retinopathy at corresponding retinal locations 1 year later. METHODS: One eye of 11 diabetic patients with nonproliferative diabetic retinopathy (NPDR) and 11 diabetic patients without retinopathy were retested 12 months after initial testing. At each time, mfERGs were recorded from 103 retinal locations, and fundus photographs were taken within 1 month of each recording. Local mfERG implicit times were measured and their z-scores were calculated based on results obtained from 20 age-matched control subjects. mfERG abnormalities were defined as z-scores of 2 or more for implicit time and z-scores of -2 or less for amplitude (P < or = 0.023). mfERG z-scores were mapped onto fundus photographs, and the relationship between baseline abnormal z-scores and new retinopathy at follow-up was examined. RESULTS: New retinopathy developed in 7 of the eyes with NPDR after 1 year. In these eyes, 70% of the mfERGs in areas of new retinopathy had abnormal implicit times at baseline. In contrast, only 24% of the responses in regions that remained retinopathy free were abnormal at baseline. Relative risk of development of new retinopathy over 1 year in the areas with abnormal baseline mfERG implicit times was approximately 21 times greater than that in the areas with normal baseline mfERGs (odds ratio = 31.4; P < 0.001). Eyes without initial retinopathy did not develop new retinopathy within the study period, although 4 of these 11 eyes had abnormal implicit times at baseline. mfERG implicit times tended to be more delayed at follow-up than at baseline in NPDR eyes, but not in eyes without retinopathy and control eyes. mfERG amplitudes had no predictive power. CONCLUSIONS: Localized functional abnormalities of the retina reflected by mfERG delays often precede the onset of new structural signs of diabetic retinopathy. Those functional abnormalities predict the local sites of new retinopathy observed 1 year later.     

Towards optimal filtering of "standard" multifocal electroretinogram (mfERG) recordings: findings in normal and diabetic subjects

AIMS: To study the effects of two commonly used pre-amplifier filtering bandwidths on normal multifocal electroretinogram (mfERG) responses and their comparative abilities to detect retinal disease. METHODS: 103 standard mfERGs were recorded simultaneously in two channels with different pre-amplifier settings (10-100 Hz and 10-300 Hz) from one eye of each of 20 normal subjects, 17 diabetics with non-proliferative diabetic retinopathy (NPDR), and 12 diabetics without retinopathy. Signal to noise ratios (SNR) of the normal subjects' first order mfERGs were compared between channels. All subjects' amplitudes and implicit times were derived using a "template stretching" method. For comparison, implicit time was also measured using a "template sliding" method. mfERG amplitudes and implicit times were compared between the channels and among subject groups. RESULTS: Normal mean amplitudes and implicit times were similar for the two channels. However, normal 10-100 Hz recordings had significantly higher SNR and lower intersubject variability than 10-300 Hz recordings. In NPDR, the 10-100 Hz channel identified significantly more implicit time and amplitude abnormalities. In the diabetics without retinopathy, 10-100 Hz filtering identified significantly more implicit time abnormalities than 10-300 Hz filtering. For both filter settings, diabetic implicit times were more often abnormal than amplitudes. The 10-100 Hz channel was superior for both implicit time measurements. CONCLUSION: Standard mfERGs recorded from normal eyes and filtered 10-100 Hz contain less noise, higher SNR, and less intersubject variability than those filtered at 10-300 Hz. This underlies the finding that the 10-100 Hz filter setting identifies more retinal dysfunction than the 10-300 Hz setting.     

利用多焦视网膜电图检测开角型青光眼患者的黄斑功能

目的：采用多焦视网膜电图（mfERG）方式检测原发性开角型青光眼（POAG）患者的黄斑区外层视网膜功能。方法对36例POAG患者和36例正常人进行mfERG检查,记录以黄班中央凹为中心5个环状视网膜区域R1（0°～2．5°）、R2（2．5°～5°）、R3（5°～10°）、R4（10°～15°）、R5（15°～20°）一阶反应 N1、P1波反应密度（单位面积的反应幅度即振幅密度值）及P1潜伏时,将一阶反应N1、P1反应密度取算术平均值产生N1-P1平均反应密度,测量POAG患者平均视野缺损值（ MD）,所得数据做线性相关分析。结果与正常对照组相比,黄斑区R1、R2环内POAG患者N1、P1平均反应密度明显减少,P1潜伏时明显延长。 R1、R2环N1、P1平均反应密度减少与平均视野缺损有显著相关性。结论由于N1、P1主要起源于外层视网膜,因此mfERG能很好的显示POAG患者黄班区外层视网膜功能损害,并与青光眼病程进展相关,为青光眼临床诊断治疗提供参考。     

Relationship Between the s-wave Amplitude of the Multifocal Electroretinogram and the Retinal Nerve Fiber Layer Thickness in Glaucomatous Eyes

Purpose

To determine whether a significant correlation exists between the amplitude of the s wave of the multifocal electroretinogram (mfERG) and the retinal nerve fiber layer thickness (RNFLT) in glaucomatous eyes.

Methods

Twenty-three eyes of 23 patients with glaucoma were studied. In all eyes, the severity of the defects in the upper visual field differed significantly from the severity of those in the lower half. Patients having visual field halves with mean deviation (MD) values lower than ?5?dB were placed in group A, and patients having visual field halves with MD values greater than ?5?dB were placed in group B. The mfERGs were elicited by 37 stimulus elements alternating from white to black in a pseudorandom binary m-sequence at a frequency of 9.4?Hz. The mfERGs in the upper and lower visual field halves were summed to yield upper and lower averaged waves. The GDx variable corneal compensator and optical coherence tomography were used to measure the RNFLT.

Results

The retinal nerve fiber layer was significantly thinner in group A than in group B. There was a significant correlation between the RNFLT and the MD values of visual field defects. The s-wave amplitude was significantly smaller in group A than in group B. The s-wave amplitude also correlated significantly with the MD and the RNFLT.

Conclusion

The significant correlations between the s-wave amplitude and the MD, and between the S-wave amplitude and the RNFLT, indicate that the s-wave receives significant contributions from the retinal ganglion cells and their axons. Jpn J Ophthalmol 2005;49:481–490 © Japanese Ophthalmological Society 2005     

Selective loss of an oscillatory component from temporal retinal multifocal ERG responses in glaucoma

PURPOSE: To evaluate electrophysiologic function in glaucoma by using a new stimulus designed to enhance ganglion cell and optic nerve head component (ONHC) contributions to multifocal electroretinogram (mfERG) responses. METHODS: mfERGs of 16 individuals with glaucoma (POAG) and 18 normal control subjects were recorded and analyzed with a VER imaging system. The stimulus had three frames inserted between each m-sequence step: a full-field dark frame (1.0 cd/m(2)), a full-field flash (200 cd/m(2)), and another dark frame. Multifocal flashes were 100 cd/m(2). The stimulus subtended approximately 40 degrees total diameter and contained 103 scaled hexagonal elements. Signals were obtained using Burian-Allen bipolar electrodes, amplified x10(6), band-pass filtered at 10 to 300 Hz, and sampled at 1200 Hz. RESULTS: Local first-order responses (kernels) consisted of a direct component (DC) followed by an induced component (IC). Nasal-temporal response asymmetries in normal eyes were most easily observed in the IC. A small but distinct oscillation in the ICs of temporal retinal responses distinguished them from nasal IC waveforms. In individuals with glaucoma, there was less asymmetry between nasal and temporal responses, mostly because of the reduction of the oscillation in the temporal retinal ICs. The amplitude of this oscillation was 4.4 +/- 2.1 nV/deg(2) in the control group and 1.8 +/- 1.2 nV/deg(2) in the glaucoma group (P < 0.0001). Amplitude and latency measures of other response features were not significantly different from normal. Amplitude of the IC oscillation was not correlated with age in either the normal or glaucoma groups. In a group of normal subjects retested 3 months later, the average test-retest repeatability was +/-12%. CONCLUSIONS: Selective loss of an oscillatory feature from IC responses in glaucoma may represent abnormalities in the inner plexiform layer of the temporal retina, where classic oscillatory potentials (OPs) are thought to arise. However, evidence suggests that this effect may also be due in part to loss of the ONHC.     

妊娠高血压综合征患者的多焦视网膜电图表现

目的研究妊娠高血压综合征(妊高征)患者的多焦视网膜电图(mfERG)及其与病情、预后的关系。方法正常对照组31例,妊高征组77例,并分为轻度、中度、重度。对所有对象行mfERG检查,分析其与妊高征程度、视网膜病变程度、母婴预后、产后随访结果的关系。结果不同程度的妊高征患者及不同程度视网膜病变的妊高征患者的mfERG表现均出现异常(P<0.05)。轻度妊高征患者即出现1、2环的视网膜反应密度降低(P<0.05)。mfERG出现异常早于视网膜出现病变(P<0.05)。与mfERG正常的相比,mfERG异常的妊高征的母婴预后较差(P<0.05)。妊高征患者产后mfERG恢复迟于视网膜病变的恢复。结论观察妊高征患者的mfERG表现有助于更好地监测病情、判断预后、指导治疗。     

Multifocal electroretinograms in early primary open-angle glaucoma

PURPOSE: To determine the utility of multifocal electroretinograms (mfERGs) in patients with early primary open-angle glaucoma (POAG) with unilateral visual field abnormalities. METHODS: mfERGs were recorded from 24 eyes of 12 cases of early POAG (stage I for 1 eye and stage II for the other eye on the Kosaki scale). The implicit times and amplitudes of the second-order kernel summed for the whole visual field, for the superior and inferior hemi-fields, and for quadrantic fields of the stage I and stage II eyes were compared. RESULTS: Neither the first- nor the second-order kernels of the mfERGs showed any changes reflecting glaucomatous visual field abnormalities. The implicit times and amplitudes of the second-order kernel summed for the whole visual field, the superior and inferior hemi-visual fields, and quadrantic visual fields of the stage I and stage II eyes were also not significantly different. CONCLUSIONS: We conclude that because the second-order kernel of the mfERG does not correlate with the visual field abnormality in early POAG, the second-order kernel of the mfERG that can be recorded at present is highly unlikely to reflect the function of the ganglion cells in the inner retinal layers.