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     

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.     

Tolerability of levocabastine eye drops

We used an oscillatory potential power method (a measure of the summed oscillatory potential activity) based on fast-Fourier transform analysis to study the oscillatory potentials in early diabetic retinopathy. The method was used in 29 diabetic patients with no ophthalmoscopically visible diabetic retinopathy, 29 diabetic patients with early signs only and 27 control subjects. The reduction in oscillatory potential power was compared with the reduction in the second and third oscillatory potential amplitudes and increase in implicit time in the diabetic patients. The amplitude of the second oscillatory potential was slightly more resistant to diabetic retinopathy than was the amplitude of the third oscillatory potential. Because the oscillatory potentials were detected by means of a high-resolution technique, their implicit times seem to be as discriminating as the oscillatory potential power in the detection of early diabetic retinopathy.     

Methodologic dependence of electroretinogram oscillatory potential amplitudes

The International Society for Clinical Electrophysiology of Vision (ISCEV) protocol for eliciting oscillatory potentials uses a considerably lower flash intensity and a different preconditioning stimulus than the only oscillatory potential protocol used to predict progression of diabetic retinopathy. To determine if the ISCEV protocol will be useful in predicting progression of diabetic retinopathy, summed oscillatory potential amplitudes were measured by both protocols in a population of diabetics. Summed oscillatory potential amplitudes measured by the ISCEV protocol, although smaller, are highly correlated with the summed oscillatory potential amplitudes measured with the higher-intensity flash. Thus, summed oscillatory potential amplitudes measured with the ISCEV protocol should be useful in predicting outcome in diabetic retinopathy. Different signal processing filters used to extract oscillatory potentials from the electroretinogram waveform have a small, but significant, effect on summed oscillatory potential amplitude. Use of the caliper-square method or the summed peak-to-trough method for measuring oscillatory potential heights had an insignificant effect on measured oscillatory potential amplitude.Abbreviation FIR finite impulse response     

不同眼轴眼振荡电位与糖尿病视网膜病变眼振荡电位相关性研究

目的比较不同眼轴眼振荡电位与糖尿病视网膜病变（DR）眼振荡电位幅值的相关性,研究不同眼轴患者视网膜微循环功能的变化。方法回顾性收集不同眼轴患者32例（32只眼）进行视网膜电流图检查,同时收集经荧光素眼底血管造影证实的Ⅲ期及Ⅳ期DR患者18例（30只眼）进行视网膜电流图检查,比较不同眼轴眼振荡电位与DR患者振荡电位的相关性。结果正常眼轴眼平均∑O为（143.81±42.47）μv,中等眼轴眼平均∑O为（93.93±28.93）μv,长眼轴眼平均∑O为（68.43±17.99）μv;Ⅲ期DR平均∑O为（108.19±21.21）μv,Ⅳ期DR平均∑O为（69.70±16.63）μv。比较5组之间的差异有统计学意义（F=16.896,P〈0.01）,中等眼轴患者∑O值与Ⅲ、Ⅳ期DR患者∑O值差异无统计学意义,长眼轴患者∑O值与Ⅲ期DR患者∑O值差异有统计学意义,与Ⅳ期DR患者∑O值差异无统计学意义。结论随着眼轴的逐渐增长,视网膜振荡电位逐渐下降。长眼轴患者视网膜的微循环功能低于Ⅲ期DR患者。     

Correlation between ERG oscillatory potential and psychophysical contrast sensitivity in diabetes

Correlation between the electroretinographic oscillatory potential and psychophysical contrast sensitivity function was examined in patients with different stages of diabetic retinopathy. Contrast sensitivity function was evaluated by Arden's grating test. The amplitude of the oscillatory potential was significantly reduced in cases with low contrast sensitivity (P < 0.01).     

Correlation between ERG oscillatory potential and psychophysical contrast sensitivity in diabetes

Correlation between the electroretinographic oscillatory potential and psychophysical contrast sensitivity function was examined in patients with different stages of diabetic retinopathy. Contrast sensitivity function was evaluated by Arden's grating test. The amplitude of the oscillatory potential was significantly reduced in cases with low contrast sensitivity (P less than 0.01).     

Electroretinographic evaluation of diabetic retinopathy: sensitivity of amplitude and time of response

Amplitude and delay of oscillatory potentials were studied in the electroretinograms (ERGs) of patients with diabetes to see which was the more sensitive for evaluating diabetic retinopathy. Loss of amplitude was more sensitive in identifying eyes with early stages of retinopathy, in which funduscopic evidence of retinopathy was still absent, whereas delay of response was more sensitive in grading eyes with later stages. With cases classified according to stage of retinopathy, loss of amplitude and delay of response, a theoretic curve of the electrophysiologic time-course of diabetic retinopathy was drawn. The curve showed that amplitude can distinguish normal from preretinopathic eyes, that with a loss of amplitude of less than 50% no retinopathy will be found ophthalmoscopically, and that with a delay of response greater than 8% the delay will correlate well with the stage of retinopathy.     

Early diagnosis of retinal changes in diabetes: a comparison between electroretinography and retinal biomicroscopy

The present study was undertaken in order to find out whether electroretinographic examinations could reveal signs of functional abnormalities before morphological changes are detected in the diabetic retina. Pattern-reversal and flash electroretinograms (ERG) and oscillatory potentials (OP) were recorded in 24 diabetics and 10 age-matched normal controls. The diabetic group consisted of 11 patients without retinopathy and 13 patients with background retinopathy. No significant changes in pattern-reversal or flash ERG or OP amplitudes were observed in the diabetic group with normal fundus or with background retinopathy. The findings imply that ERG examination with the described techniques does not reveal retinal dysfunction in diabetics before retinopathy can be detected by means of retinal biomicroscopy.     

A comparison of photopic and scotopic electroretinographic changes in early diabetic retinopathy.

Previous studies of early diabetic retinopathy have shown that oscillatory potential (OP) amplitudes are reduced in many diabetic patients. OP amplitude is believed to be a more sensitive indicator of the development of future retinopathy than b-wave amplitude of the scotopic electroretinogram (ERG). Because OPs measured to a bright white flash reflect both rod and cone system activity, it is important to compare OP amplitudes to photopic ERG measures as well as scotopic measures in early diabetic retinopathy. In this study, OPs and ERG responses were measured under photopic and scotopic conditions in a group of diabetic patients. Although OPs were reduced in amplitude in the diabetic group, several other parameters of the scotopic and photopic b-waves were impaired. The results indicate that b-wave activity may indicate retinal changes in early diabetic retinopathy in the same manner as the OPs.     

Oscillatory potentials in electroretinographic evaluation of retinal function in insulin-dependent diabetics without retinopathy

PURPOSE: Can oscillatory potentials be a useful method for detection of retinal dysfunction in insulin-dependent diabetics without retinopathy? MATERIAL AND METHODS: In this study scotopic oscillatory potentials (OPs) were obtained in 35 subjects (70 eyes) with insulin-dependent diabetes without retinopathy (mean disease duration--5 years) and in 15 healthy subjects (30 eyes). This examination was performed according to the recommendations of the International Society of Clinical Electrophysiology of Vision (ISCEV). The oscillatory potentials were extracted from the maximal combined response by high-pass filtering. We analysed amplitude and peak-latencies of the first three electroretinographic oscillatory potentials O1, O2, O3, index of wavelets [sum of amplitudes (O1 + O2 + O3)] and compared with the results of the control group. RESULTS: In group of patients with insulin-dependent diabetes without retinopathy, we received statistically significant reduction of amplitude O1 (p < 0.003) and index of wavelets (p < 0.04). Reduced amplitude O1 was obtained in 10%, index of wavelets in 31.4% of analysed eyes. We didn't observe statistically significant changes in amplitudes O2, O3 and latencies O1, O2, O3. CONCLUSIONS: Our results suggest that retinal dysfunction is present in insulin-dependent diabetics without retinopathy 5 years after onset of the disease. The sum of amplitudes (O1 + O2 + O3) was the most sensitive parameter of retinal abnormalities. It seems reasonable to have more frequent ophthalmological examination of the diabetics with abnormal oscillatory potentials.     

Changes in the oscillatory potentials in the electroretinogram during the evolution of diabetic retinopathy

Oscillatory potentials where intensely studied in diabetic patients with various degrees of retinopathy. Classical reports pointed out the early reduction of their amplitude, as well as of their latency, while a and b waves remained still normal. A prognostic value was attached to these modifications, the reduction of oscillatory potentials being correlated with a ten time higher probability of developing a high risk retinopathy. 27 diabetic patients where investigated electroretinographically by us. No significant variation of the amplitude of oscillatory potentials was observed during the progression of diabetic retinopathy.     

国产羟苯磺酸钙胶囊对糖尿病视网膜病变患者视网膜震荡电位的影响

目的:观察国产羟苯磺酸钙胶囊对糖尿病视网膜病变(diabetic retinopathy,DR)患者视力、视网膜振荡电位(retina oscillatory potentials,OP)的影响和疗效及安全性。方法:将60例双眼糖尿病视网膜病变患者随机平均分为试验组和对照组。试验组口服国产羟苯磺酸钙胶囊(多贝斯)500mg,3次/d;对照组口服进口羟苯磺酸钙胶囊(导升明)500mg,3次/d,连续服用6mo。治疗前两组患者的一般资料均衡性好。治疗结束后分别检查患者的视力、OP,根据治疗前后两者的变化进行评分。比较治疗结束后两组评分的差异。结果:国产羟苯磺酸钙胶囊对DR患者的视力、OP的影响结果与进口产品导升明相似,两者之间无统计学差异(P>0.05)。结论:国产羟苯磺酸钙胶囊多贝斯可以改善DR患者的血管功能、改善患者视力,是治疗DR的有效药物。     

Electroretinographic evaluation in adult diabetics

In cross-sectional fashion, we recorded the maximal combined response and 30-Hz flicker responses in 178 adult diabetics and 40 normal controls according to the recommendations of the International Society of Clinical Electrophysiology of Vision. The oscillatory potentials were extracted from the maximal combined response by high-pass filtering. The clear media and attached retina were criteria for inclusion in this study. The data were statistically analyzed with the expectation that this procedure may provide a new feature that could have some clinical significance. Timing delays occurred more frequently than amplitude reductions in the maximal combined response and flicker responses, while amplitude reductions were more common in the first and second oscillatory potentials. The hypernormal b-wave amplitude was rare. The summed amplitude of the oscillatory potentials was highly correlated with the total power of the oscillatory potentials (the frequency domain). A reduction of the second oscillatory potential amplitude was more common than a reduction of the summed amplitude or total power. The electroretinographic component that demonstrates retinal dysfunction in the earlier stage may be a valuable indicator. In the early stage, a delay in the a-wave time and a reduction in the second oscillatory potential amplitude were the most frequent abnormalities: analysis of variance demonstrated that the summed amplitude of the oscillatory potentials and second oscillatory potential amplitude and time were the most sensitive measures of the diabetic retina. Hence, the second oscillatory potential amplitude may be the most sensitive and valuable indicator representing a quantitative measure of overall retinal dysfunction.     

视网膜激光光凝治疗糖尿疴陛视网膜病变的疗效分析

目的 观察糖尿病性视网膜病变（DR）眼行视网膜激光光凝前后视力、无灌注区、视网膜新生血管及闪光视网膜电图（f-ERG）的变化.方法 前瞻性病例对照研究.2009年1月至2010年7月在新疆维吾尔自治区人民医院眼科行视网膜激光光凝的增殖前期糖尿病性视网膜病变（PPDR）72眼和增殖性糖尿病性视网膜病变（PDR）48眼纳入研究.在光凝前1周及之后1个月行视力、荧光素眼底血管造影及f-ERG检查.对患眼视力、视网膜新生血管及无灌注区消退情况进行计数,记录光凝前后患跟视杆反应b波、混合反应b波、震荡电位、视锥反应b波及30 Hz振幅.治疗前后的数据采用配对t检验进行分析.结果 视网膜激光光凝后,PPDR组中48眼视力保持不变,24眼下降;54眼无灌注区全部消退,16眼部分消退,2眼未消退.PDR组中12眼视力提高,26眼保持不变,10眼下降;24眼新生血管全部消退,16眼部分消退,8眼未消退.光凝前后患眼视杆反应b波振幅分别为（186.7±34.1）μV和（106.7±24.8）μV;混合反应b波振幅分别为（381.2±60.4）μV和（273.2±47.8）μV;振荡电位振幅分别为（66.6±12.4）μV和（86.6±18.7）μV;视锥反应b波振幅分别为（97.4±13.5）μV和（67.2±9.4）μV;30 Hz振幅分别为（24.1±8.4）μV和（20.1±6.4）μV,差异均有统计学意义（t=5.672、5.343、3.427、3.578、2.979,P均＜0.01）.结论 视网膜激光光凝后,大部分DR眼的视力提高或保持稳定,无灌注区及新生血管消退,明显改善了视网膜的血液循环,是治疗糖尿病性视网膜病变的有效方法.     

Effects of aldose reductase inhibitor (M79175) on ERG oscillatory potential abnormalities in streptozotocin fructose-induced diabetes in rats

The effects of an aldose reductase inhibitor (M79175) on electroretinogram (ERG) oscillatory potential abnormalities was studied in rats with streptozotocin fructose-induced diabetes. The ERG oscillatory potential was recorded under scotopic conditions without general anesthesia in the diabetic rats, before and 4, 8 and 12 weeks after administration of M79175. The ERG tracings were analyzed for peak latencies, peak intervals and amplitudes; the peak latencies and intervals were prolonged and the amplitudes were reduced in untreated diabetic rats, but the prolongation of the peak latencies and intervals were suppressed in diabetic rats receiving M79175. The amplitudes were reduced in the treated rats as in the untreated rats. The results of this investigation suggest that M79175 is effective to suppress progression of diabetic retinopathy in its early stage.     

Oscillatory potentials. History,techniques and potential use in the evaluation of disturbances of retinal circulation

The oscillatory potentials seem to reflect severe disturbances in the retinal (and perhaps choroidal) circulation. In some cases of diabetic retinopathy with severe microangiopathy, the oscillatory potentials may be selectively reduced or extinguished while the amplitude of the a- and b-waves of the ERG remains normal. A correlation appears to exist between severely reduced oscillatory potentials and a circulatory deficiency in the retina. This selective reduction of the oscillatory potentials during advancing retinopathy is considered to be indirect evidence that they are generated independently from the mechanism producing the primary components (the a- and b-waves). The usefulness of the oscillatory potentials in the prognosis of retinal disease, particularly in diabetic retinopathy, is reviewed. The historical background, the techniques and instrumentation necessary to produce and record them, the experimental data available on the site of their origin, the clinical significance to data and the experimental efforts in our laboratory are summarized.     

Lobular delayed choroidal perfusion as an early angiographic sign of diabetic retinopathy: a preliminary report

Between January 1982 and December 1983 stereo colour photography covering 10 standard fields of 30 degrees and fluorescein angiography were performed in 64 consecutive patients with diabetes mellitus who had no clinical evidence of diabetic retinopathy. Fifty-two patients were excluded on the basis of the slightest photographic or angiographic evidence of retinopathy or any other ocular disease. Electroretinogram oscillatory potentials were recorded in the remaining 12 patients. Four of the 12 had normal oscillatory potentials, colour photographs and angiograms, while 8 had angiographic evidence of lobular delayed choroidal perfusion and abnormal oscillatory potentials. Although only a small number of patients in the preclinical stages of diabetic retinopathy were studied, the results warrant that further attention be given to lobular delayed choroidal perfusion, which may represent early evidence of choroidal involvement in diabetic retinopathy.     

Local multifocal oscillatory potential abnormalities in diabetes and early diabetic retinopathy

PURPOSE: To study retinal dysfunction in diabetes and early nonproliferative diabetic retinopathy (NPDR) using a new method to analyze local multifocal electroretinogram oscillatory potentials (mfOPs). METHODS: One eye of each of 26 normal subjects, 16 diabetic subjects without retinopathy (NoR), and 16 diabetic subjects with early NPDR was examined. Slow-flash multifocal electroretinograms (sf-mfERGs) were recorded from the central 45 degrees, and stereo fundus photographs of the diabetic eyes were taken. The first-order (K1), induced first-order (K1i), and second-order (K2) response components were extracted from each retinal location, and K1i and K2 were added to create Ks2. Responses from 35 contiguous areas were digitally filtered 90 to 225 Hz to isolate the mfOPs. The signal-to-noise ratio (SNR) of the mfOPs was calculated, and abnormality was defined as SNR below the fifth percentile of the normal subjects. RESULTS: Combining the K1i and K2 components to form Ks2 before isolation of the mfOPs by digital filtering increased the SNR. Mean Ks2 and K1 mfOP SNRs were abnormal in 25% and 19% of the NoR eyes, respectively, and both were abnormal in 62% of the NPDR eyes. The retinal distributions of the local Ks2 and K1 mfOP abnormalities overlapped, but they differed. Furthermore, local Ks2 mfOP abnormalities were preferentially associated with retinal sites containing NPDR but K1 mfOP abnormalities were not. CONCLUSIONS: The cells that contribute to the generation of local mfOPs are affected by diabetes and, to a greater degree, by early NPDR. The results suggest that fast adaptive mechanisms influencing the mfOPs are most abnormal at retinal sites containing NPDR.     

Factors affecting visual outcomes after small-incision phacoemulsification in diabetic patients

PURPOSE: To examine the factors affecting visual outcome after phacoemulsification and evaluate the use of preoperative visual potential in assessing the visual prognosis in diabetic patients. SETTING: Department of Ophthalmology, University of Texas Medical Branch, Galveston, Texas, USA. METHODS: In a retrospective chart review of 1345 consecutive patients who had uneventful small-incision phacoemulsification, operated eyes from 106 diabetic and 55 nondiabetic control patients were selected. Data on demographics, level of retinopathy, perioperative glycosylated hemoglobin (HbA(Ic)), surgical duration, preoperative best corrected visual acuity (BCVA), and visual potential were collected. RESULTS: The age, sex, preoperative BCVA, and visual potential in the diabetic and control eyes were comparable. Throughout the postoperative period, BCVA was worse of the diabetic group. At 1 year, BCVA was 20/40 in 82.1% of the diabetic group and 94.7% of the control group (P =.01). The most important factors affecting postoperative BCVA included coexisting diabetes and preoperative level of retinopathy. No correlation was found between perioperative and postoperative BCVA. Diabetic patients were less likely than control patients to achieve a BCVA better than or equal to the preoperative visual potential at 4 years (hazard ratio 0.6; 95% confidence interval, 0.4-0.9; P =.011). Patients with nonproliferative diabetic retinopathy were nearly 5 times less likely (P =.023) and patients with proliferative diabetic retinopathy 30 times less likely (P <.0001) to achieve a postoperative BCVA of 20/40 than diabetic patients without retinopathy. CONCLUSIONS: Although uneventful small-incision phacoemulsification improved visual acuity in diabetic patients, this group had an overall worse visual outcome than nondiabetic patients. The most important predictors of visual outcome were coexisting diabetes and the extent of preoperative retinopathy. Methods used to assess preoperative visual potential provided a reasonable estimate of postoperative BCVA in diabetic patients. Given the inverse association between the level of retinopathy and visual outcome, it may be better to perform cataract extraction in diabetic patients during earlier stages of retinopathy.