New noncorneal HK-loop electrode for clinical electroretinography

A new noncorneal electrode for clinical electroretinography was developed. It consists of a thin wire forming a loop modeled to fit into the lower conjunctival sac. Electrical contact is made with the scleral conjunctiva through an exposed portion of otherwise insulated wire. The recorded pattern electroretinograms are in the same amplitude range as if recorded by the gold foil electrode, while the flash electroretinograms with the new electrode are of about two-thirds the amplitude of corneal electrodes. The new electrode is more durable and hence less expensive than gold foil electrodes and can likewise be used without topical anesthetic. Cleaning is easy and effective. The electrode rarely causes discomfort and produces stable responses for at least 2 hours. The electrode aims to match stability of skin electrodes with sensitivity of fragile foil and fiber electrodes.     

Performance of the DTL electrode compared to the Jet contact lens electrode in clinical testing

To compare the recording characteristics of the DTL fiber and Jet contact lens electrodes, ERG responses were recorded from 20 normal subjects using the ISCEV standard clinical protocol. In each subject, the DTL electrode was placed in the right eye and the Jet contact lens in the left eye after 30 min of dark-adaptation. After presenting standard dark- and light-adapted stimuli, each response was analyzed for a- and b-wave amplitude and implicit time. Each subject was then asked to rate the comfort of each electrode. Responses recorded with the DTL are larger and faster for the dark-adapted dim white and red flashes. In contrast, the Jet electrode records larger responses for the dark-adapted standard flash and light-adapted flashes. Of these differences, only the standard flash is statistically significant. However, overall the DTL electrode has greater variability than the Jet electrode across all recordings. The DTL and Jet electrodes cannot be used interchangeably as demonstrated by a Bland and Altman analysis of agreement. Thus, separate normative values need to be collected for each type of electrode to accurately assess retinal function. Based on the comfort assessment of the two electrodes, the subjects preferred the DTL electrode over the Jet electrode. Due to the superior comfort level of the DTL and its similarities to the Jet contact lens electrode in ERG recordings, the DTL electrode appears to be a good alternative to the Jet electrode in routine clinical testing when used with the appropriate normative values.     

Safety and efficacy evaluation of a new ERG electrode (the LVP electrode); Part II. Flash ERG pilot study

A new disposable, non-contact electrode (LVP electrode) was evaluated for use in recording flash ERG. A comparison of DTL and LVP electrodes showed reproducible waveforms for all components analysed. There was a good correlation obtained between the DTL and LVP electrodes. The LVP electrode is safe, less expensive and has less movement of the fiber due to its rigidity.     

Recording the oscillatory potentials of the electroretinogram with the DTL electrode

Suprathreshold photopic oscillatory potentials recorded with a DTL electrode were compared to those obtained with a Lovac corneal electrode. The overall oscillatory potential response (sum of oscillatory potentials) recorded with the DTL electrode was half of that obtained with the Lovac electrode. However, there was no evidence of a selective attenuation (or amplification) of any given oscillatory potential with the DTL electrode. Similarly, the oscillatory potential relative amplitude ratios and the peak times of the oscillatory potentials were identical for both electrodes. Our findings clearly indicate that the DTL electrode is adequate to record the high-frequency oscillatory potentials. Given the low cost and ease of use, as well as the disposable nature of the DTL electrode, we believe that electroretinographic specialists should seriously consider a wider utilization.     

Safety and efficacy evaluation of a new electrode (the LVP electrode), Part I. Pattern ERG pilot study

We have designed a less expensive, non-corneal ERG electrode. Named as the LVP electrode, this new disposable electrode was found safe and reliable for pattern ERG recordings.     

用DTL电极测量我国正常人视网膜电图的明视负波反应

目的用DTL电极测量我国正常人视网膜电图的明视负波反应(PhNR)的正常值,探讨正常人PhNR的特征。方法应用美国ESPION视觉电生理仪及一次性使用的DTL电极测量我国正常人65例(112眼)的PhNR。全视野刺激器由LED发出光源,选用蓝色背景光(亮度为10cd/m2),刺激光为红色(刺激光强度分别为1、5cd.s/m2和7cd.s/m2)。按10岁一年龄组分组统计PhNR的振幅和潜伏期。结果经统计学分析,将年龄组间无显著统计学差异的组作合并后,分成<50岁和≥50岁两个年龄组。这两组的正常振幅值在1、5cd.s/m2和7cd.s/m2时分别为(-38.94±10.21)μV和(-32.41±7.76)μV,(-38.51±10.97)μV和(-34.52±8.90)μV,(-38.62±9.98)μV和(-33.96±9.81)μV,正常潜伏值分别为(65.83±4.06)ms和(69.86±5.68)ms,(66.17±6.48)ms和(71.33±4.90)ms,(65.81±6.71)ms和(70.40±4.61)ms,表明两个年龄组的振幅和潜伏值均有显著统计学差异。结论一次性DTL电极可防止交叉感染。研究确定了按相关年龄分组的我国正常人PhNR的正常值。     

Guidelines for clinical electroretinography in the dog

These procedures described for the dog ERG were approved at the 1st European Conference on Veterinary Visual Electrophysiology in Vienna, Austria, May 30, 2000. Dr. Narfström was Chair of the Committee for a Harmonized ERG Protocol, appointed by the European College of Veterinary Ophthalmology (ECVO), and Dr. Ofri was secretary. The other coauthors are committee members. Guidelines for ERG procedures in other animal species for clinical and laboratory studies are planned for in the future and the present guidelines are planned to be revised on a biannual basis. A brief report of the recommended procedures is available in the Conference Proceedings book.     

Multifocal electroretinography in central serous chorio-retinopathy and assessment of the reproducibility of the multifocal electroretinography

Purpose: To measure and compare the difference of multifocal electroretinography (mERG) in control subjects and patients with central serous chorio-retinopathy(CSCR) and assessing the reproducibility of the multifocal electroretinography. Methods: Sixteen cases of control subjects and 12 cases of central serous chorio-retinopathy were tested with the Visual Evoked Response Imaging System science4.2 made by EDI company of America. The results of the left eye of each control subject and patient were used for statistical evaluation by the Mann–Whitney U test. Repeat measurements were performed on 11 control subjects. Wilcoxon technique were used to quantify the reproducibility of the test. Results: The P₁ waveform average response density of 1–3 rings in central serous chorio-retinopathy were decreased statistically. There was no significant difference between repeat measurements on 11 individuals. Conclusion: Multifocal electroretinography can be used to quantify the visual function of the affected area in chorio-retinopathy and showed good agreement in the data distribution for the repeat measurements.     

近视患者光学相干断层成像与多焦视网膜电图的变化

近视是生活中最常见的眼科疾病,它严重威胁着人们的眼部健康.目前,很多研究者应用光学相干断层成像(optical coherence tomography,OCT)以测量近视的视网膜结构变化,视网膜结构变化则是由屈光增加引起的眼轴增长导致的.另外,人们利用多焦视网膜电图进行视网膜功能的测量.全局闪光多焦视网膜电图(multifocal electroretinography, mf-ERG)可以同时测量视网膜内层和外层的功能.有些研究者在同一个研究中联合应用OCT和mf-ERG,以便于更好地了解近视引起的结构与功能变化的联系.我们需要更多的研究以了解二者之间的联系.     

Effects of the beta1-selective adrenergic antagonist betaxolol on electroretinography in the perfused cat eye

The effects of the ₁-selective adrenergic antagonist betaxolol on electroretinography (ERG) were studied in the isolated and arterially perfused cat eye. Betaxolol increased the perfusion flow rate, significantly at the administrations of more than 50M concentrations and induced a dose-related, reversible increase in the amplitudes of both the a-wave and b-wave of ERG. These results suggest that the calcium-channel blocking mechanism of betaxolol has a beneficial influence on ocular blood flow and retinal electrical activity in response to light. As it is known that ERG is a good indicator of the functional integrity of the retina, this indicates that betaxolol could be an ideal drug for treating glaucoma in which ischemia is involved to some extent.     

激光治疗后不同病程中心性浆液性脉络膜视网膜病变多焦视网膜电图的研究

目的观察经激光治疗后的中心性浆液性脉络膜视网膜病变(central serous chorioretinopathy,CSC)多焦视网膜电图(multifocal electroretinography,mfERG)特点。方法应用RETI Scan multifocal ERG Version3.15系统对25例CSC患者进行双眼mfERG的随访测定,61个六边形从中央到周边共分5个环,测定31°视野范围的一阶反应(first-orderkernel),分别进行双眼比较。结果3~6个月病程组N1波幅值于环2患眼与对侧眼比较差异有显著性(P<0.01),P1波幅值于环1、环2患眼与对侧眼比较差异均有显著性(P<0.01);7~20个月病程组N1波幅值于环1患眼与对侧眼比较差异有显著性(P<0.05),P1波幅值于环1、环2患眼与对侧眼比较差异有显著性(P<0.05)。潜伏期比较,不管是3~6个月病程组还是7~20个月病程组,其患眼与对侧眼比较均无明显差异(P>0.05)。结论3~6个月病程组及7~20个月病程组其黄斑中心区mfERG幅值患眼仍低于对侧眼,mfERG检查能反映其黄斑区功能变化。     

正常大鼠发育过程中视网膜电图a波的特点

目的观察正常大鼠发育过程中暗适应视网膜电图（ERG）a波的变化特点。方法实验研究。采用RETI-scan系统,环形角膜电极和不锈钢针状电极,对8组不同日龄大鼠（21、25、32、35、37、46、60及90d）记录不同刺激光强度下（0．03、0．95、3和9．5cd·S·m^-2）的暗适应ERG。导出数据,先采用Matlab7．4对数据进行预处理,然后根据数学模型使用Excel提供的规划求解模型拟合a波并分析模型中的2个参数：饱和波幅（Rmp3）与敏感度（S）。结果不同刺激光强度下Rmp3的最小值均出现在25日龄大鼠,光强为0．03cd·S·m^-2时其最大值出现在60日龄大鼠,余则出现在46日龄大鼠。8组大鼠的S均与刺激光强度呈线性关系（S=ks·Ⅰ＋bs）,除60日龄大鼠外,曲线的斜率ks基本保持不变,约为0．09,日龄主要影响常量bs。结论正常大鼠ERGa波的饱和波幅及敏感度均不同程度地受日龄的影响。     

The changes of multifocal electroretinography in the early stage of photodynamic therapy for choroidal neovascularization

To investigate short-term changes in the multifocal electroretinography (ERG) recordings after photodynamic therapy (PDT) for choroidal neovascularization (CNV), 16 patients (17 eyes) with classic CNV confirmed by fluorescein angiography (FA) and indocyanine green angiography (ICGA), including 11 cases (12 eyes) of exudative age-related macular degeneration (AMD), two cases (two eyes) of pathological myopia and three cases (three eyes) of idiopathic causes, were treated using PDT with verteporfin. The multifocal ERGs of these patients were tested with VERIS Science^TM4.0 imaging system. The latencies and average response densities of all six ring retinal regions were measured and compared before PDT and 3 or 7 days after PDT. The latencies and amplitude densities of the N₁ and P₁ waves in all six rings remained unchanged at 3 or 7 days post-treatment (p>0.05). Therefore, there is no significant evidence to suggest an adverse effect from PDT for classic CNV on the outer retinal function in the early stage of treatment, with the aid of the multifocal ERG recordings.     

Hereditary retinal degeneration in the Abyssinian cat: Developmental studies using clinical electroretinography

Electroretinography was performed in 10 Abyssinian cats, homozygous for a hereditary retinal degenerative disease but still with an ophthalmoscopically normal retina, and in 11 mixed-breed controls, all between the ages of 8 and 104 weeks. A significant reduction of maximum dark-adapted b-wave amplitude was found in affected kittens as young as 8–16 weeks when compared with controls, although there was no major difference in dark-adapted b-wave threshold or implicit time for the b-wave between affected and controls. For cats 33–104 weeks, similar results were obtained except for the b-wave threshold, which was elevated 2.5 log units in one of the affected cats. No significant difference in 30-Hz cone flicker responses were found between affected and controls at any age studied. In the time period 17–32 weeks affected Abyssinian kittens could not be differentiated from controls by means of the electroretinogram. The significant reduction in scotopic b-wave maximum amplitudes in young affected kittens (8–16 weeks) in conjunction with normal thresholds suggests an early drop-out of rods. It is clear that affected kittens can be differentiated electrophysiologically from controls long before there are ophthalmoscopic signs of retinal disease.     

玻璃体腔注射康柏西普治疗湿性年龄相关性黄斑变性的早期mfERG变化

目的：利用多焦视网膜电图(mfERG)评价玻璃体腔注射康柏西普的湿性年龄相关性黄斑变性(age-related macular degeneration,ARMD)患者视网膜功能的早期变化。

方法：经眼底荧光血管造影确诊为湿性ARMD患者接受玻璃体腔注射康柏西普眼用注射液(0.05mL/0.5mg),记录注射前及注射后1mo的最佳矫正视力及mfERG各环N1、P1波潜伏期及P1波振幅密度。

结果：共20例20眼患者纳入研究,平均LogMAR视力从注射前0.80±0.48提高到注射后0.65±0.50(P<0.001),环1平均振幅密度从注射前39.59±16.60nV/deg²提高到注射后的53.81±20.41nV/deg²(P=0.006),振幅密度的改变与视力的改变呈正相关(r=-0.776,P<0.001)。

结论：对于湿性ARMD患者玻璃体腔注射康柏西普短期内能改善黄斑中心凹的功能。     

A tricolor light source for stimulation and adaptation in electroretinography

A Ganzfeld light source, fitted on an electroretinogram contact lens, is described. The light source can provide blue, green, or red flashes with intensities over a range of 3.6 log units. It can also be used to provide a continuous light-adapting background in each of the above-mentioned colors, simultaneously presenting the possibility of emitting flashes. The control unit and the light source can be powered by a small battery pack.     

光动力疗法联合玻璃体腔注射Bevacizumab治疗息肉状脉络膜血管病变前后多焦视网膜电图的改变

目的 应用光动力疗法（PDT）联合玻璃体腔注射Bevacizumab治疗息肉状脉络膜血管病变（PCV）,探讨治疗前后患者多焦视网膜电图（mfERG）的变化.方法 前瞻性研究.共纳入黄斑型PCV患者13例（13眼）,男8例,女5例,年龄（60.2±7.7）岁.所有患者接受吲哚菁绿眼底血管造影（ICGA）指导下6 mg/m2剂量光敏剂Verteporfin的PDT治疗83 s,3 d后行玻璃体腔注射Bevacizumab 1.5 mg（0.06 ml）.治疗前及治疗后1、3、6个月,记录视力、眼底荧光素血管造影（FFA）、mfERG各环的潜伏期和振幅密度变化及并发症情况.采用Friedman＇s检验观察视功能指标的变化情况,当检验发现显著性改变时,采用Wilcoxon检验以比较治疗前后视功能的改变.结果 仅一例患者因为FFA的持续渗漏而于治疗后3个月随访时接受了再次治疗.治疗后平均logMAR视力逐渐提高,治疗后3个月及6个月视力与治疗前比较,差异有统计学意义（Z=-2.823,P=0.005;Z=-2.620,P=0.009）.与治疗前相比,6个环的潜伏期无明显下降.治疗后3个月,1环P1波（Z=-2.271,P=0.023）及2环的N1、P1波（Z=-2.202,P=0.028;Z=-1.992,P=0.046）振幅密度明显升高.治疗后6个月,1环P1波（Z=-2.432,P=0.015）及2环的N1、P1波Z=-2.158,P=0.031;Z=-2.118,P=0.034）振幅密度的升高仍具有统计学意义.结论 PDT联合玻璃体腔注射Bevacizumab治疗PCV后病灶血管渗漏改善,视力提高,外层视网膜功能部分恢复.mfERG可以作为一种评价联合治疗后PCV患者视功能变化情况的良好指标.     

Comparisons of contact lens, foil, fiber and skin electrodes for patterns electroretinograms

Pattern electroretinograms are small physiologic signals that require good patient cooperation and long recording times, particularly when conditions are not optimal. Six electrodes were compared to evaluate their efficacy. Pattern electroretinograms were recorded in eight healthy volunteers to high-contrast, pattern-reversal checks (40′ width) with Burian-Allen, DTL fiber, C-glide, gold foil, HK loop and skin electrodes. Raw data for 320 reversals were analyzed off-line to evaluate signal amplitude, quality, P50 and N95 peak times, artifact rate and electrical noise. Insertion time, impedance and subjective comfort were also assessed. The Burian-Allen contact lens electrode gave the largest signal and lowest impedance but was the least comfortable and had the highest artifact rate (p<0.01). A skin electrode on the lower eyelid produced the smallest pattern electroretinogram with the poorest quality (p<0.05). The four other electrodes were foil or fiber electrodes in contact with the tear film, conjunctiva and/or the inferior cornea. The signal from these showed only minor differences. When electrodes are compared for pattern electroretinograms recording, the foil and fiber electrodes do not differ substantially but contact lens and skin electrodes show substantial disadvantages.     

ERG electrode in pedriatic patients: Comparison of DTL fiber,PVA-gel,and non-corneal skin electrodes

Hard contact lens electrodes have been the type most frequently used in pediatric electroretinogroply but they are not well-tolerated by patients. The Dawson Trick Litzkow fiber electrode is better tolerated but it is fragile and difficult to sterilize. A new electrode made from anomalous polyvinyl alcohol gel is inexpensive, has stable electrical recording properties, and can be discarded after use. Dermal electrodes have been used for electroretinogram recording for some time; however, there are few reports that directly compare their performance against standard contact lens assemblies. We compared the DTL and the polyvinyl gel electrodes in the same group of subjects and investigated their recording characteristics along with non corneal skin electrodes placed on the infraorbital ridge. Signal-averaged electroretinogram were obtained under both scotopic and photopic stimulation conditions and the implicit time and amplitudes of the a- and b-waves were determined. Overall, dermal recordings generally had shorter implicit times and lower amplitudes than with the fiber or gel electrodes. The dermal electrodes were best tolerated and outlasted the corneal in repeated use. Since amplitude characteristics of the dermal electrodes were generally about 50% of that obtained with corneal electrodes, we feel that under standardized conditions they are acceptable for most clinical recording situations in infants and young children.