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.     

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     

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.     

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.     

Measuring oscillatory potentials: Fourier analysis

Studying the oscillatory potentials in diabetic retinopathy, the authors experienced several problems interpreting results of digital filtering. The main problem was the separation of the first potential from the a-wave, since their frequencies are within the same range. To improve the procedure of measuring implicit times and of calculating amplitudes, the filtering was started with a finite impulse response filter and followed by a fast Fourier transform. The power of the oscillatory potential was calculated by determining the dominant frequency in the Fourier transformed response and expressed in microwatts. A group of normal subjects was compared with a group of early diabetic retinopathy patients. It appears that even in pathological circumstances a quantitative expression of the oscillatory potential is possible.     

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     

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.     

亚临床期糖尿病视网膜病变与肾损害的对比研究

目的 从临床角度对比早期糖尿病视网膜病变(DR)和糖尿病肾病(DN)两者间的关系。 方法 对102例非胰岛素依赖型糖尿病患者做反映早期DR和DN敏感指标OPs和UAER、GFR的检测,进行两者关系的对比分析。结果 UAER正常的DR前期糖尿病患者,OPs总波辐降低,同时GFR呈相关性升高,OPs与GFR呈负相关(r=-0.63,P<0.01)。 结论 早期DR和DN呈平行关系,且两者似乎均与微血管异常有关,可能DR和DN是糖尿病微血管病变在不同部位的表现。     

视网膜振荡电位和视觉诱发电位检测在糖尿病视网膜病变前期诊断中应用

目的:观察尚未发生眼底病变的糖尿病确诊患者在不同病程时期视网膜振荡电位(OPs)和视觉诱发电位(VEP)的变化情况。方法:采用国际标准法对35例70眼正常人进行OPs和VEP的检测,对94例188眼未发生眼底病变糖尿病确诊患者按病程长短分为3组,分别进行OPs和VEP的检测。结果:各实验组与对照组相比表现为OPs幅值的降低和VEP峰值降低,潜时值延长,P<0.01,有显著统计学差异。各实验组之间相比表现为病程越长OPs幅值越低和VEP峰值越低,潜时值越长,P<0.01,有显著统计学差异。结论:糖尿病患者在眼底尚无病变前,其OPs和VEP已经出现异常,并且随着糖尿病病程的延长,各项指标的变化更加明显。因此,采用OPs和VEP的联合检测可以为糖尿病视网膜病的早期诊断提供依据。     

Oscillatory potentials of local macular ERG in diabetic retinopathy

The oscillatory potentials (OPs) in electroretinogram (ERG) have clinical values in measuring retinal functions of the early stage of diabetic retinopathy. However, OPs have, until now, been evaluated as components of total ERG recorded with a full field stimulus over the entire retina. Therefore, little information could be obtained about the macular condition (diabetic retinopathy). Using focal stimuli, we successfully recorded OPs in the human macular region. We modified our previously reported system for recording local macular ERG under the fundus monitor with an infrared television fundus camera. We evaluated macular OPs with simultaneously recorded a- and b-waves in many patients with diabetic retinopathy. In some kinds of early diabetic maculopathy, the macular OPs were selectively reduced, leaving the a- and b-waves intact. The macular OPs can be a valuable indicator in assessing the macular function in diabetic maculopathy.     

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.     

Variability in clinically measured photopic oscillatory potentials

Oscillatory potentials found on the ascending phase of the electroretinogram b-wave probably originate in some element(s) of the inner plexiform layer. As oscillatory potentials are particularly sensitive to changes in retinal, and possibly choroidal, blood flow, they have been used extensively to provide clinical measures of the degree of retinal ischemia during the progression of diabetic retinopathy. Recent studies in our laboratories have disclosed previously unreported significant variability in the photopic oscillatory potentials on repeated measures even in tightly controlled conditions. The amplitude of five recordable light-adapted wavelets exhibited considerable intra- and inter-subject variability. Until further investigation can determine factors affecting standardization of testing, it appears that changes in oscillatory potential implicit times rather than in amplitudes are a better measurement in clinical neurophysiology.     

The electroretinogram in diabetic retinopathy.

Electroretinography (ERG) is an objective method of evaluating retinal function. Since its introduction to clinical practice in the 1940s, it has become a useful and routine diagnostic clinical tool in ophthalmology. This review summarizes the role of ERG as a clinical technique for evaluating the progression of diabetic retinopathy and as a research tool for increasing our understanding of the pathophysiology of diabetic retinopathy. Most studies show unequivocally that the different types of ERG tests detect local abnormalities or widespread pathology, even in very early stages of the disease. It seems plausible that measurements from ERG recordings, particularly the oscillatory potentials, may be useful for predicting progression from nonproliferative to the more sight-threatening stages--preproliferative or proliferative--of diabetic retinopathy. Some recent work implies that the ERG can also be a useful diagnostic method for discriminating between eyes with diabetic retinopathy and those without the condition.     

CHANGES OF OSCILLATORY POTENTIALS OF THE ERG IN DIABETIC RETINOPATHY

Abstract— Disturbances of the oscillatory potentials of the ERG are examined in diabetic patients with and without vascular lesions of the retina. More specifically, the changes of the oscillatory potentials are investigated in relation to the manifestation and evolution of diabetic retinopathy and neovascularization of the optic disk and the retina. Particular stress is laid on the direct relation between the disturbances of the oscillatory potentials and the occurrence of neovascularization, as well as on the prognostic significance of these disturbances.     

Changes of Oscillatory Potentials and Photopic Negative Response in Patients with Early Diabetic Retinopathy

Purpose

To investigate the clinical significance of the oscillatory potentials (OPs) and photopic negative response (PhNR) of the electroretinogram (ERG) in patients with early diabetic retinopathy.

Methods

One hundred two diabetic patients with diabetic retinopathy at different stages were examined. Thirty-two age-matched normal controls were also studied. Full-field maximal and photopic cone ERGs were recorded. The amplitudes and implicit times of the OPs, cone b wave, and PhNR were compared at the different stages of diabetic retinopathy.

Results

The a and b wave amplitudes of the maximal scotopic ERGs remained unchanged despite advancing stages of retinopathy, but the OP amplitudes were significantly attenuated even at an early stage of diabetic retinopathy. The amplitudes of both the PhNR and cone b wave were reduced at an early stage of diabetic retinopathy. Analysis of the receiver operating characteristic curves demonstrated that the amplitudes and implicit times of the OPs were more sensitive and specific than those of the PhNR in detecting changes of retinal function in the early stages of diabetic retinopathy.

Conclusions

The amplitudes of the OPs and PhNR progressively decrease with the progression of diabetic retinopathy. The PhNR amplitudes were reduced along with the cone b wave, indicating that earlier change of the PhNR in diabetic patients reflects reduced input to the retinal ganglion cell from the distal retina. The amplitudes and implicit times of the OPs are better indicators than those of the PhNR in detecting functional decreases in patients with early diabetic retinopathy.?Jpn J Ophthalmol 2006;50:367–373 © Japanese Ophthalmological Society 2006     

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.     

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.     

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。     

VECPs and optic disc damage in diabetes

Abnormal VECP latencies can be found in type 1 diabetic patients without retinopathy or neuropathy. The pathogenesis of this finding is still unclear. The authors report the clinical history of a diabetic patient showing normal fundus, normal oscillatory potentials, and pathological VECP latency on first examination. The clinical follow-up of this patient showed rapid evolution toward proliferative retinopathy. This finding is suggestive of a peripheral (optic nerve or retina) origin of the VECP impairment.     

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.