Oscillatory potentials in early diabetic retinopathy

To study the oscillatory potentials in early diabetic retinopathy the authors developed a new power measurement based on the fast Fourier transform. Three groups totalling 46 patients were examined, varying from nonvisible to preproliferative diabetic retinopathy. The oscillatory potentials expressed in microwatts were measured under scotopic and photopic conditions. The data of the three groups are compared with those of a group of 22 normal individuals. The oscillatory potential power measurement appears to be a reliable method in detecting diabetic retinopathy at an early stage.     

Oscillatory potentials, macular recovery time, and diabetic retinopathy through 3 years of intensified insulin treatment

Forty-five diabetic patients, 18 to 45 years of age, with mild or no retinopathy, were randomly assigned to continuous subcutaneous insulin infusion (CSII), multiple injections (Mls), and conventional insulin treatment (CIT). The effects of near-normoglycemia (CSII and MI) on oscillatory potentials (electroretinography [ERG]) and macular recovery time (nyctometry) were studied prospectively for 41 months. Before randomization, the amplitudes of oscillatory potentials were negatively correlated to age (P = 0.002) and positively correlated to the diameter of retinal veins (P less than 0.05). Men had shorter macular recovery time than women (P = 0.03). Nyctometry and oscillatory potentials were not related to mean blood glucose values, glycosylated hemoglobin (HbA1), retinopathy, blood pressure levels, or duration of diabetes. Changes in metabolic control (MI and CSII; P less than 0.01) and in microaneurysms and hemorrhages (CSII and CIT) during the study did not affect oscillatory potentials or nyctometry. Soft exudates (15 patients) and proliferative retinopathy (1 patient) transiently developed with MI and CSII regimens. No changes in oscillatory potentials or nyctometry were observed and no pretreatment characteristics of these parameters predicted the occurrence of these ischemic lesions. At the stage of proliferation, however, lowered amplitudes of oscillatory potentials and lengthened macular recovery time were observed.     

Oscillatory potentials as an indicator of functional changes in diabetic retinopathy

In diabetics it can be shown that after successful coagulation of the retina an increase in the amplitude of the oscillatory potentials (OP) takes place, indicating stabilization of retinal function. In Type I diabetics hypernormal and hyponormal OP amplitudes are seen prior to decompensation of the retina. Optimal regulation of diabetic metabolism can bring these pathologic OPs back into the normal range.     

Oscillatory potentials of multifocal electroretinogram retinopathy

Purpose: To investigate the physiological function in the posterior pole of the retina in eyes with preproliferative diabetic retinopathy using the oscillatory potentials (OPs) of the multifocal electroretinogram (mfERG). Methods: Multifocal ERGs were recorded from 61 eyes of 61 patients with preproliferative diabetic retinopathy (pre-PDR) and 16 eyes of 16 age-similar normal control subjects. The amplitudes and implicit times of the first positive component, P1, and the OPs of the mfERGs, recorded with a slow m-sequence, from diabetics were compared with those in normal control subjects. Among the 61 eyes, the mfERGs were recorded before and after panretinal photocoagulation (PRP) in 19 eyes of 19 patients. Results: The amplitudes of P1 and OPs were significantly smaller in all tested areas in the diabetics as compared with those in the normal subjects, and the degree of reduction was greater for the OPs than P1. The implicit times of P1 and OPs were significantly delayed in the diabetics in the peripheral tested regions (20–40°) but not in the central area. After PRP, the amplitudes of P1 were markedly reduced in all areas tested; however, the changes of the P1 implicit time were not significant. The amplitudes of the OPs were significantly reduced in the peripheral regions after PRP; however, the changes in the implicit times were not significant. Conclusions: These results indicate that retinal function in the posterior pole is markedly impaired in eyes with pre-PDR. PRP altered the mfERGs significantly, however, the reductions were limited to the amplitude.     

Oscillatory potentials and permeability of the blood-retinal barrier in noninsulin-dependent diabetic patients without retinopathy

Electroretinography and vitreous fluorophotometry were performed in 36 eyes of 36 noninsulin-dependent diabetic patients and in 32 eyes of 32 healthy control subjects between the ages of 30 and 59 years. Fluorescein fundus angiograms showed no abnormalities in either group. Peak implicit time of the first deflection of the oscillatory potential, interpeak interval between the first and second deflections, and the sum of the amplitudes of the upward deflections were analyzed. Inward permeability of the blood-retinal barrier was calculated by vitreous fluorophotometry and computer simulation. The peak implicit time of the first deflection and the interpeak interval between the first and second deflections of the oscillatory potential were significantly longer in diabetic patients than in control subjects (P less than 0.01). No significant difference in inward permeability of the blood-retinal barrier existed between the two groups. These results indicate that a selective delay in the peak implicit time of the oscillatory potential (neurosensory retinal abnormality) may be present in noninsulin-dependent diabetic patients, representing retinal functional changes before changes in blood-retinal barrier permeability are apparent.     

Oscillation potentials in diabetic retinopathy

The authors give an account of hitherto assembled knowledge on the mode of induction, origin and basic characteristics of oscillation potentials of the human electroretinogram. They evaluate quantitative and qualitative changes of oscillation potentials in different diseases and retinal damage, in particular diabetic retinopathies. The authors deal also with possible clinical application of the follow-up of oscillation potentials.     

Oscillatory potentials in electroretinograms of the human macular region

Using focal stimuli, we successfully recorded oscillatory potentials (OPs) in electroretinograms of the macular regions of 72 normal volunteers. The OPs consisted of three to four wavelets with a mean peak interval of approximately 6.5 msec, consistent with that recorded with conventional full-field stimuli over the entire retina. The changes of amplitude in response to the spot sizes and ring stimuli suggested that the distribution of OPs is different from that in a- and b-waves in human macular region.     

糖尿病视网膜病变的视网膜振荡电位

目的 研究振荡电位（ＯＰｓ）在糖尿病视网膜病变（ＤＲ）不同阶段的表现,探讨ＤＲ早期诊断的敏感性指标,并为ＤＲ国内分期提供功能学信息。方法 选择８３名糖尿病患者、１５５眼,进行眼底检查、眼底摄像;按国内ＤＲ分期将患眼分成眼底无改变、１期、２期、３期、４期但无玻璃体出血等５组,对所有患眼按国际标准化方法进行ＯＰｓ检测。选择４３只正常眼作对照。结果 ＯＰｓ总和振幅、ＯＰ２振幅在眼底无改变时下降,在１期时进一步下降;ＯＰ３振幅在１期时较对照下降,ＯＰ１振幅在２期对较对照和无改变组下降,ＯＰ４在３期时较对照下降,４期的ＯＰ２振幅以及３期和４期的ＯＰｓ总振幅分别与０期、１期和对照组的相应指标有差异。结论 ＯＰｓ和ＯＰ２振幅在ＤＲ临床前期下降,是ＤＲ早期诊断的敏感与客观性指标;ＯＰｓ及其子波振幅在ＤＲ早期和病变分期呈负相关,     

Electroretinographic oscillatory potentials in diabetic retinopathy

The oscillatory potentials of the electroretinogram in dark and light adaptation were evaluated by Fourier transform in 87 diabetics and 74 age-matched controls. The study consisted of four groups: normal control, no observable diabetic retinopathy, background diabetic retinopathy and proliferative diabetic retinopathy. A reduction in the amplitude of each oscillatory potential, the summed amplitudes, the area and the total power of the oscillatory potentials as well as delayed implicit time of each oscillatory potential peak in dark and light adaptation could be found in patients with background diabetic retinopathy and proliferative diabetic retinopathy. The amplitude of oscillatory potential 4 in dark adaptation and the total power of the oscillatory potentials in light adaptation seemed to be affected in patients with no observable diabetic retinopathy. The implicit time of oscillatory potential 2 in dark adaptation was valuable to distinguish between patients with no observable diabetic retinopathy and background diabetic retinopathy.Abbreviations NC normal control - NDR no observable diabetic retinopathy - BDR background diabetic retinopathy - PDR proliferative diabetic retinopathy     

糖尿病视网膜病变黄斑区视网膜厚度变化的研究

目的探讨糖尿病视网膜病变(diabetic retinopathy,DR)黄斑区视网膜厚度变化规律及与荧光素眼底血管造影、静脉血糖化血红蛋白AIC(HbAIC)的关系.方法正常对照组30例(30眼),糖尿病(diabetes mellitus,DM)病人84例(107眼)并分为无糖尿病视网膜病变(DM无DR)、糖尿病视网膜病变Ⅰ、Ⅱ、Ⅲ、Ⅳ期(DRⅠ、Ⅱ、Ⅲ、Ⅳ期)5组.采用光学相干断层成像仪(OCT)测量以黄斑中心凹为中心的6mm直径区域视网膜厚度,以地形图分9区显示.对各组间黄斑区视网膜厚度进行比较.观察糖尿病病人黄斑区荧光素渗漏与视网膜厚度变化关系;对黄斑中心凹1mm直径范围视网膜厚度与HbAIC值进行相关分析.结果正常人黄斑中心凹1mm直径区域视网膜厚度为(168±17)μm,糖尿病病人各组相应区域视网膜厚度分别为(179±16)μm、(205±34)μm、(217±43)μm、(291±96)μm、(408±117)μm.DRⅠ、Ⅱ期间视网膜厚度无显著性差异(P＞0.2),其余各组均有显著性差异(P＜0.05).仅弥漫性荧光素渗漏时视网膜厚度显著增加(P＜0.05),视网膜厚度与HbAIC无关.结论糖尿病视网膜病变早期黄斑区视网膜厚度已有增加,并随着病程的发展,视网膜厚度增加明显,但与HbAIC无关.     

ERG Oscillatory Potentials in Infants

Purpose: Study the scotopic and photopic oscillatory potentials (OPs) of the electroretinogram (ERG) in 10-week old infants. Methods: Term-born 10-week old infants (n = 15) and adults (n = 12) were tested. Full-field ERGs were recorded under scotopic and photopic conditions. The records were filtered (75–300 Hz) to demonstrate the oscillatory wavelets. The amplitudes and implicit times of the infants’ OPs were compared to those in adults and also to amplitudes of the saturated photoreceptor responses. Results: In infants, the mean OP amplitudes are similar in scotopic and photopic conditions and do not vary significantly with OP number. Infants’ OPs are significantly smaller than in adults, with scotopic OPs averaging 19% of that in adults and photopic OPs averaging 47%, whereas the amplitudes of the saturated photoreceptor responses are 43% and 66% of those in adults. Mean interpeak intervals are similar in infants and adults, indicating oscillatory behavior at a frequency of 155 Hz in scotopic conditions and 135 Hz in photopic conditions. Conclusions: In young infants, the OPs are relatively immature compared to the photoreceptor responses, with the immaturity of the scotopic responses being more marked than that of the photopic responses.