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     

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.     

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     

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.     

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 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 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.     

糖化血红蛋白及视觉电生理检测在糖尿病视网膜病变早期诊断的价值

目的:研究糖尿病性视网膜病变(diabetic retinopathy,DR)时糖化血红蛋白(hemoglobin A1c,HbA1c)及视网膜振荡电位(oscillatory potentials,Op)的动态变化。方法:对确诊的2型糖尿病患者用检眼镜检查进行筛选,以眼底荧光素血管造影(fundus fluorescein angiography,FFA)进行明确分期,对各期患者在3a内定期行HbA1c测定6次,行Op检查2次,最后1次检测配合FFA检查,统计分析结果。结果:HbA1c水平控制在4.99%±0.58%为预防DR发生发展的安全参考值;HbA1c水平持续在9.77%±1.57%时,DR进展明显加快;Op总波幅下降副度<10.6±4.9μV可作为预测视网膜病变未进展的参考值;Op总波幅下降幅度>31.6±9.7μV,则可作为预测2型糖尿病患者发生DR或DR发生进展的依据。结论:HbA1c,OP结合,能预测DR的发展。     

A comparison of oscillatory potential and pattern electroretinogram measures in diabetic retinopathy

Both basic and clinical electrophysiological investigations have established that the oscillatory potentials (OP) and pattern electroretinogram (PERG) appear to originate from retinal sites that are in proximity. The OPs, subcomponents of the flash ERG, have been shown to reflect disturbances in retinal circulation, and OP amplitude attenuation or loss may be a distinctive feature of diabetic retinopathy. The PERG has been shown to be abnormal in diseases of the optic nerve and ganglion cell body. Thus its relative sensitivity for detection of electroretinal abnormalities in diabetic retinopathy is in question. This study assessed the sensitivity of ERG and OP measures in their detection of abnormalities of electroretinal function in diabetic patients referred to our laboratory. Thirty-five adult Type I patients were studied: 21 with background retinopathy (BR group), 14 with no evidence of background retinopathy (No BR group), and 25 normal control subjects.Monocular OPs were recorded to full-field ganzfeld stimulation at four stimulus intensities. PERGs were obtained from checkerboard pattern reversal stimulation (checksize = 30 arc). Peak-to-peak amplitude and peak implicit time measures of PERGs and OPs were obtained. Subsequent multivariate analysis demonstrated significant differences between normals and diabetic patients, including diabetics with no clinical evidence of retinopathy. In addition, the OP and PERG implicit times appear to be unaffected while OP and PERG amplitudes were diminished in patients with background retinopathy. Only OP amplitudes were found to be significantly diminished in diabetic patients with no photographic evidence of background retinopathy. The PERGs were normal in these patients. Overall, the OP amplitude measures were more sensitive than PERG measures in detecting abnormalities in patients with no retinal photographic evidence of background 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.     

糖尿病视网膜病变临床前期的视功能变化分析

目的:观察糖尿病视网膜病变临床前期患者的图形视觉诱发电位、视网膜振荡电位以及视神经纤维层厚度的变化,评估糖尿病视网膜病变临床前期视功能的变化.方法:收集糖尿病视网膜病变临床前期的2型糖尿病患者89例,以及健康志愿者80例.均采用罗兰电生理检查系统检测图形诱发电位(P-VEP)的P100潜伏期和振幅、视网膜振荡电位(Ops)总振幅和各子波振幅,以及RTVueOCT检测视神经纤维层厚度(RNFL),对检测结果进行比较分析.结果:糖尿病组患者的P100潜伏期比正常对照组的P100潜伏期明显延长,差异有统计学意义(t=-10.633,P=0.000).糖尿病组患者的P100振幅比正常对照组的P100振幅明显降低,差异具有统计学意义(t=3.610,P=0.000).糖尿病组患者OPS总振幅及各子波振幅均比正常对照组OPS总振幅及各子波振幅明显降低,差异具有统计学意义(t=17.320,P=0.000;t=3.239,P=0.000;t=4.144,P=0.000;t=7.666,P=0.000;t=5.319,P=0.000).与正常对照组相比,糖尿病组患者的平均RNFL厚度及鼻侧、下方及颞侧RNFL厚度均无明显改变,差异无统计学意义(t=1.730,P=0.085;t=0.664,P=0.547;t=1.923,P=0.063;t=1.814,P=0.072).而上方RNFL厚度明显变薄,与正常对照组相比差异显著(t=7.989,P=0.000).结论:在糖尿病视网膜病变临床前期的患者,视乳头及黄斑区均出现了视功能改变.     

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.     

Electroretinographic oscillatory potentials in insulin-dependent diabetes patients: A long-term follow-up

PURPOSE: The aim of this research was to study the relevance of long-term follow-up of electroretinographic oscillatory potentials (OPs) in predicting the onset of minimal non-proliferative diabetic retinopathy in insulin-dependent diabetes patients. METHODS: A total of 80 insulin-dependent diabetics, with normal fundi and normal OPs at first examination, were followed prospectively for 10 years. Oscillatory potentials were measured and fundus examinations performed once or twice per year. RESULTS: During follow-up, 35% of patients developed diabetic retinopathy after a mean disease duration of 12 +/- 2 years. A decrease in OP amplitudes was seen in 46% of this group, but reductions were also seen in the 25% of patients whose fundi remained normal. Statistical analysis of best-fit survival curves shows a significant difference (p < 0.001) in the point of Kaplan-Meiers' curve maximal linearity (TmaxS). CONCLUSIONS: It appears that eyes with reduced OP amplitude have a greater probability of developing diabetic retinopathy. Subnormal OP amplitudes are not proof of real concomitant visible vascular damage, but may reflect a predisposition to functional neurosensorial disorder.     

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.     

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.     

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.     

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。     

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.     

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).