Multifocal electroretinogram delays reveal local retinal dysfunction in early diabetic retinopathy.

PURPOSE: To identify local retinal abnormalities in diabetic patients with and without retinopathy, by using the multifocal electroretinogram (M-ERG). METHODS: Electroretinograms were recorded at 103 discrete retinal locations in each eye of eight persons with nonproliferative diabetic retinopathy (NPDR) and eight diabetic persons without retinopathy, using VERIS (EDI, San Mateo, CA). The amplitude and implicit time of each local (first-order) retinal response were derived and compared with normal values obtained from 16 age-matched, nondiabetic subjects. Maps of local response amplitude and implicit time were compared with fundus photographs taken at the time of testing. RESULTS: In eyes with NPDR, the implicit times of responses from retinal sites manifesting clinical pathologic fundus lesions (e.g., microaneurysms and focal edema), were markedly delayed (e.g., up to 7 msec from normal). Responses from adjacent retinal sites that were more normal in clinical appearance were also delayed, but to a lesser extent (e.g., 2-5 msec). Smaller, yet significant local response delays were also found in eyes without retinopathy. By contrast, local response amplitudes bore no consistent relationship to fundus abnormalities in eyes with retinopathy, and amplitudes were typically normal in eyes without retinopathy. CONCLUSIONS: The M-ERG reveals local retinal dysfunction in diabetic eyes even before retinopathy. The magnitude of delay of local ERG implicit time reflects the degree of local clinical abnormality in eyes with retinopathy. Local response delays found in some eyes without retinopathy suggest that the M-ERG detects subclinical local retinal dysfunction in diabetes. Analysis of M-ERG implicit time, independent of amplitude, improves the sensitivity of detection of local retinal dysfunction in diabetes.     

Retinal function in normal and diabetic eyes mapped with the slow flash multifocal electroretinogram

PURPOSE: It has been suggested that late components of the standard multifocal electroretinogram (mfERG) are preferentially affected by diabetes mellitus. The slow-flash (sf-)mfERG stimulates with flashes separated by dark periods, facilitating interpretation of late first-order response components compared with standard multifocal stimulation. Retinal function and response component changes were examined using the sf-mfERG in diabetic subjects with and without diabetic retinopathy. METHODS: Eighteen control subjects, 12 diabetic patients without retinopathy and 17 diabetic patients with nonproliferative diabetic retinopathy (NPDR), were tested monocularly. A total of 103 areas of the central 45 degrees were stimulated by pseudorandom 100-cd/m2 flashes separated by at least 53.3 ms. Major components and the amplitude of the first-order sf-mfERGs were examined. Each subject's N1, P1, and N2 implicit times (ITs) and scalar product amplitudes (SPs) were measured at all 103 retinal locations and converted into z-scores based on the control values. Abnormalities were defined as z-scores greater than 2.33 (P < 0.01). RESULTS: Local functional abnormalities were found in both the diabetic patients with NPDR and in those without retinal disease. In both groups of diabetic patients, most abnormalities occurred more frequently in the inferior retina. Later components (P1 and N2) of the local sf-mfERGs were not preferentially affected by diabetes. The local SP and P1 IT measures distinguished the subject groups better than N1 IT and N2 IT. CONCLUSIONS: Local functional retinal abnormalities in diabetic persons with or without NPDR can be detected and mapped by the sf-mfERG. Diabetes and NPDR do not, however, preferentially affect the late P1 and N2 response components.     

Multifocal electroretinogram delays predict sites of subsequent diabetic retinopathy

PURPOSE: To examine the potential of abnormal mfERGs to predict the development of diabetic retinopathy at corresponding retinal locations 1 year later. METHODS: One eye of 11 diabetic patients with nonproliferative diabetic retinopathy (NPDR) and 11 diabetic patients without retinopathy were retested 12 months after initial testing. At each time, mfERGs were recorded from 103 retinal locations, and fundus photographs were taken within 1 month of each recording. Local mfERG implicit times were measured and their z-scores were calculated based on results obtained from 20 age-matched control subjects. mfERG abnormalities were defined as z-scores of 2 or more for implicit time and z-scores of -2 or less for amplitude (P < or = 0.023). mfERG z-scores were mapped onto fundus photographs, and the relationship between baseline abnormal z-scores and new retinopathy at follow-up was examined. RESULTS: New retinopathy developed in 7 of the eyes with NPDR after 1 year. In these eyes, 70% of the mfERGs in areas of new retinopathy had abnormal implicit times at baseline. In contrast, only 24% of the responses in regions that remained retinopathy free were abnormal at baseline. Relative risk of development of new retinopathy over 1 year in the areas with abnormal baseline mfERG implicit times was approximately 21 times greater than that in the areas with normal baseline mfERGs (odds ratio = 31.4; P < 0.001). Eyes without initial retinopathy did not develop new retinopathy within the study period, although 4 of these 11 eyes had abnormal implicit times at baseline. mfERG implicit times tended to be more delayed at follow-up than at baseline in NPDR eyes, but not in eyes without retinopathy and control eyes. mfERG amplitudes had no predictive power. CONCLUSIONS: Localized functional abnormalities of the retina reflected by mfERG delays often precede the onset of new structural signs of diabetic retinopathy. Those functional abnormalities predict the local sites of new retinopathy observed 1 year later.     

Association between multifocal ERG implicit time delays and adaptation in patients with diabetes

PURPOSE: Local first-order multifocal electroretinogram (mfERG) implicit time (K1-IT) delays have proved to be important and predictive indicators of retinal function in diabetes. To better understand the nature of these delays, the authors examined the spatial association between K1-IT and second-order amplitudes (K2-SNR; a measure of adaptation) in diabetic and control subjects. METHODS: The authors studied K1-IT, K1 amplitude, and K2-SNRs of responses from 35 retinal zones. These were recorded from 20 diabetic patients without retinopathy, 20 patients with mild to moderate nonproliferative diabetic retinopathy (NPDR), and 30 healthy control subjects. The K1-IT and K2-SNR measurements were then adjusted according to normative and subject median values to reduce or remove the effects of retinal location, intersubject differences, and abnormally small K1 amplitudes. RESULTS: There was no significant association between K1-IT and K2-SNR in the control group (P > 0.05) and only a marginal association in the NoRet group (P = 0.05). In contrast, longer K1-ITs were significantly associated with reduced K2-SNRs in NPDR subjects (P < 0.01). In the NPDR eyes, zones without retinopathic lesions showed a significant association between K1-IT and K2-SNR (P < 0.01). CONCLUSIONS: The results suggest that an association between longer K1-IT and reduced K2-SNR (abnormal adaptation) develops after the appearance of NPDR, but this association does not depend on the presence of colocalized retinopathic lesions.     

Multifocal electroretinogram in diabetic subjects

PurposeTo identify local retinal abnormalities and evaluate the nature and extent of retinal dysfunction in diabetics using full field electroretinogram (ERG) and multifocal ERG (MF-ERG) and to determine the correlation between features of optical coherence tomography (OCT) and MF-ERG.MethodsTwenty-eight normal subjects (Control Group; 56 eyes) and 37 patients (72 eyes) with diabetes mellitus (DM Group) were evaluated. In the DM Group, 17 eyes had no retinopathy (grade 1), 18 eyes had early non proliferative diabetic retinopathy (NPDR) (grade 3), 16 eyes had late NPDR (grade 4), 21 eyes had proliferative diabetic retinopathy (PDR) (grade 5). Full field ERG and MF-ERG, were used to assess the effects of diabetic retinopathy on retinal function. OCT and fluorescein angiography were used to assess and compare morphological changes with functional changes in diabetes mellitus.ResultsIn diabetic patients without retinopathy (17 eyes), the amplitudes of the second order component of MF-ERG were reduced and implicit times were delayed, while only implicit times of first order component of MF-ERG were delayed but the amplitudes of first order component were normal. In diabetic patients with retinopathy (55 eyes), the overall amplitudes were reduced and peak implicit time increased in the first order component and second order component.OCT of the DM Group showed the fovea of eyes with edema were thicker than the Normal Group. The fovea of eyes with cystoid macular edema (CME) were significantly thicker than the fovea of eyes with diffuse swelling. The implicit times of MF-ERG were directly correlated with foveal thickness.ConclusionMF-ERG reveals local retinal dysfunction in diabetic patients. MF-ERG offers the advantage of topographic mapping of retinal dysfunction. The magnitude of delay of MF-ERG implicit time reflects the degree of local clinical abnormalities in eyes with retinopathy. Local response delays found in eyes without retinopathy detects subclinical local retinal dysfunction in diabetics. The combination of OCT and MF-ERG may provide objective criteria for evaluation and assessment of diabetic retinopathy.     

Towards optimal filtering of "standard" multifocal electroretinogram (mfERG) recordings: findings in normal and diabetic subjects

AIMS: To study the effects of two commonly used pre-amplifier filtering bandwidths on normal multifocal electroretinogram (mfERG) responses and their comparative abilities to detect retinal disease. METHODS: 103 standard mfERGs were recorded simultaneously in two channels with different pre-amplifier settings (10-100 Hz and 10-300 Hz) from one eye of each of 20 normal subjects, 17 diabetics with non-proliferative diabetic retinopathy (NPDR), and 12 diabetics without retinopathy. Signal to noise ratios (SNR) of the normal subjects' first order mfERGs were compared between channels. All subjects' amplitudes and implicit times were derived using a "template stretching" method. For comparison, implicit time was also measured using a "template sliding" method. mfERG amplitudes and implicit times were compared between the channels and among subject groups. RESULTS: Normal mean amplitudes and implicit times were similar for the two channels. However, normal 10-100 Hz recordings had significantly higher SNR and lower intersubject variability than 10-300 Hz recordings. In NPDR, the 10-100 Hz channel identified significantly more implicit time and amplitude abnormalities. In the diabetics without retinopathy, 10-100 Hz filtering identified significantly more implicit time abnormalities than 10-300 Hz filtering. For both filter settings, diabetic implicit times were more often abnormal than amplitudes. The 10-100 Hz channel was superior for both implicit time measurements. CONCLUSION: Standard mfERGs recorded from normal eyes and filtered 10-100 Hz contain less noise, higher SNR, and less intersubject variability than those filtered at 10-300 Hz. This underlies the finding that the 10-100 Hz filter setting identifies more retinal dysfunction than the 10-300 Hz setting.     

Multifocal VEP (mfVEP) reveals abnormal neuronal delays in diabetes

This pilot study examined the diagnostic role of multifocal visually evoked potentials (mfVEP) in a small number of patients with diabetes. mfVEP, mfERG, and fundus photographs of both eyes of five patients with diabetes, three with nonproliferative diabetic retinopathy (NPDR) and two without NPDR were examined. Thirteen control subjects were also examined. Eighteen zones were constructed from the 60-element mfVEP stimulus array. mfVEP implicit time (IT) and amplitude (SNR) differences were tested between subject groups. We also examined whether there was a difference in function for patches with and without retinopathy in the NPDR group. Lastly, we compared mfVEP and mfERG results in the same patients. We found significant mfVEP IT differences between controls and all patients with diabetes, controls and diabetics without retinopathy, and between controls and diabetics with retinopathy. The subject groups did not differ significantly in terms of SNR. In the retinopathy group, ITs from zones with retinopathy were significantly longer than ITs from zones without retinopathy (P = 0.016). mfERG IT was more frequently abnormal than mfVEP IT. In addition, mfERG hexagons were twice as likely to be abnormal if the corresponding mfVEP zone was abnormal (P < 0.05). mfVEP implicit times are significantly delayed in patients with diabetes even when there is no retinopathy. These cortical response results are similar, albeit considerably less abnormal, than those previously reported for retinal (mfERG) responses in patients with diabetes. A correlation exists between the location of abnormal mfERG hexagons and abnormal mfVEP zones.     

Formulation and evaluation of a predictive model to identify the sites of future diabetic retinopathy

PURPOSE: To formulate and test a model to predict the development of local patches of nonproliferative diabetic retinopathy (NPDR), based on multifocal electroretinogram (mfERG) implicit times and candidate diabetic risk factors. METHODS: mfERGs and fundus photographs were obtained from 28 eyes of 28 diabetic patients during an initial and 12-month follow-up examination. mfERG implicit times were derived at 103 locations using a template-stretching method, and a z-score was calculated in comparison with 20 age-matched normal subjects. Thirty-five nonoverlapping retinal zones were constructed by grouping two to three adjacent stimulated locations, and each zone was assigned the maximum z-score within it. Zones containing initial retinopathy were excluded from further analysis. The probability that new retinopathy would develop in the remaining zones by the follow-up examination was modeled based on the mfERG implicit time z-score for the zone and other candidate diabetic risk factors determined during the initial visit. Data collected from four previously untested diabetic subjects and the other eye of eight previous subjects during their second year follow-up were used to test the predictive model. RESULTS: After 1 year, new retinopathy developed in 11 of the 12 NPDR eyes and 1 of the 16 eyes without initial retinopathy. After accounting for the correlation among zones within each eye, a predictive model was formulated with the variables mfERG implicit time, duration of diabetes, presence of retinopathy (NPDR or no retinopathy), and blood glucose level at initial visit. The area under the receiver operating characteristic (ROC) curve of this multivariate model is 0.90 (P <0.001). The predictive model has an expected sensitivity of 86% and a specificity of 84%, which was verified by the test data. CONCLUSIONS: The development of diabetic retinopathy over a 1-year period can be well predicted by a multivariate model. The inclusion of local mfERG implicit times allowed the model to identify the specific sites of future retinopathy.     

亚临床期糖尿病视网膜病变的早期诊断

目的:探讨亚临床期糖尿病视网膜病变的早期诊断。方法:横断面研究。无糖尿病正常人30例30眼(对照组);内分泌科确诊为2型糖尿病,经检眼镜、眼底荧光血管造影检查无视网膜病变(NDR)患者35例35眼;非增殖性糖尿病视网膜病变(non-proliferative diabetic retinopathy,NPDR)患者38例38眼。分别对其行多焦视网膜电图(multifocal retina electroretinogram,mf-ERG)、对比敏感度(contrast sensitivity,CS)及视网膜中央动脉彩色多普勒检查。采用单因素方差分析及SNK-q法进行统计学分析。结果:NDR患者即出现P1波振幅下降,N1波潜时延长,且与视网膜病变程度相关(P<0.05);NDR患者CS值在中、高频段出现下降(P<0.05),NPDR患者CS值全频段下降(P<0.05);视网膜中央动脉(CRA)血流在对照组与NDR组间差异无统计学意义(P>0.05),在对照组、NDR组与NPDR组间差异有统计学意义(P<0.05)。结论:mf-ERG和CS是糖尿病患者早期视功能评价的敏感指标,随着病变发展CRA血流也出现改变。     

多焦视网膜电图检测糖尿病早期视功能的变化

目的：了解多焦视网膜电图（mfERG）在糖尿病患早期视功能的变化规律。方法：将所有被检分为正常对照组（33例）、糖尿病无视网膜病变组（63例）以及单纯期糖尿病视网膜病变组（43例）。采用mfERG对上述3组进行检测,比较3组mfERG一阶反应N1波与P1波的潜伏期与反应密度。结果：在糖尿病无视网膜病变组中,N1波与P1波反应密度低于正常对照组,异常范围位于环1一环3。其中P。波反应密度在单纯期糖尿病视网膜病变组中进一步降低。N1波与P1波的潜伏期在糖尿病无视网膜病变组中的变化无统计学意义,在糖尿病视网膜病变组中延长,异常范围扩大到环4与环5。结论：mfERG在糖尿病视网膜病变出现之前已发生异常变化,且能够定量地反映随着病情的进展,视功能的损害程度及范围。     

重度非增生性与增生性糖尿病视网膜病变多焦视网膜电图一阶函数核的特征分析

目的对比并分析糖尿病视网膜病变(diabetic reti-nopathy,DR)重度非增生期及增生期的多焦视网膜电图(mul-tifocal electroretinogram,mERG)一阶函数核的变化特征。方法选取DR患者46例72眼分为2组:一组为重度非增生性糖尿病视网膜病变(non-proliferative diabetic retinopathy,NPDR)患者23例38眼,另一组为增生性糖尿病视网膜病变(proliferative diabetic retinopathy,PDR)患者23例34眼。设立对照组为正常健康人23例34眼。采用罗兰的多焦视觉电生理检查仪进行mERG一阶函数核反应检查,提取数据后分析比较2组患者mERG1~5环的N1波、P1波的振幅密度值及峰时值。结果PDR组的N1波和P1波的振幅密度值比NPDR组下降,第1环的差异均有显著统计学意义,2~5环N1波的差异无统计学意义,P1波的差异有统计学意义;PDR组的N1波和P1波的潜伏期比NPDR组延迟,2种波形第1环的差异均无统计学意义,2~5环的差异有统计学意义(N1波4环除外)。结论DR从非增生期进入增生期,mERG一阶函数的N1和P1波在黄斑中心凹区振幅密度值下降明显,而在黄斑区外视网膜则以潜伏期的延长为明显。N1和P1波的振幅密度值对反映视细胞功能更为敏感,而潜伏期则可能与视网膜缺血的关系相对密切。     

The correlation between optical coherence tomographic features and severity of retinopathy,macular thickness and visual acuity in diabetic macular edema

Purpose To investigate the correlation between the features of optical coherence tomography (OCT) and the severity of concurrent retinopathy, central macular thickness (CMT), and best-corrected visual acuity in clinically significant diabetic macular edema.Methods In a prospective study, OCT was performed in 55 eyes of 55 patients with clinically significant diabetic macular edema, in 58 eyes of 30 patients with diabetes without retinopathy, and in 40 eyes of 21 healthy control subjects. The OCT features were categorized into: type 1, sponge-like retinal swelling; type 2, cystoid macular edema; type 3, serous retinal detachment; and type 4, vitreofoveal traction.Results The CMT in eyes with diabetic macular edema was significantly higher than in eyes of healthy controls or in eyes of diabetic patients without retinopathy (P < 0.001). Visual acuity correlated with CMT in diabetic macular edema (r = 0.558, P < 0.001). The prevalence of OCT type 1 was significantly higher in eyes with mild-to-moderate non-proliferative retinopathy (NPDR) than in eyes with severe NPDR to proliferative retinopathy (PDR) (P = 0.0069). The prevalence of OCT types 3 and 4 was significantly higher in eyes with severe NPDR to PDR than in eyes with mild-to-moderate NPDR (P = 0.0056). OCT type 1 showed the least CMT (P < 0.001) and the best visual acuity (P = 0.002).Conclusions There was a significant correlation between OCT patterns of clinically significant diabetic macular edema and severity of retinopathy, CMT, and visual acuity.     

Using Multifocal ERG Responses to Discriminate Diabetic Retinopathy

Purpose: Increase the accuracy in classifying subjects with or without early diabetic retinopathy, by analyzing the multifocal electroretinogram (mfERG) responses. Method: The mfERG was recorded for 14 control subjects (Normal) and 26 non-insulin dependent diabetic patients, 16 of the patients had no apparent retinopathy (NDR), the other 10 had mild to moderate non-proliferative retinopathy (NPDR). The first order kernel (K1) and the first slice of second order kernel (K21) of the mfERG were summed across the field and exported as trace arrays. The feature subset was selected from the kernel arrays by criterion of inter-intra distance and sequential forward searching strategy. Based on the selected features, Fisher’s linear classifiers were trained and the classification error rates were given. Result: With one feature selected, the error rates of the classifiers were bigger than 23% between the NDR and NPDR subjects. When six features were selected to train the classifiers, the classification error rate decreased to 6.5% between Normal and NDR, 0 between Normal and NPDR, and 9.6% between NDR and NPDR. The criterion function of inter-intra distance was calculated for each feature in the K1 and K21 arrays. According to rank of the function value, during early DR, deformations should be easier to find at the front limb of peaks N2 and P1 on the K1 trace, and at the front limb of peak N2 on the K21 trace. As a conclusion, the multifocal ERG responses have great potentials in exploring diabetic retinopathy, assisted with the pattern classification methods.     

无黄斑水肿的NPDR患者中心凹区mfERG与视网膜厚度的研究

目的：分析非增生性糖尿病视网膜病变(nonproliferative diabetic retinopathy,NPDR)无黄斑水肿的患者黄斑中心凹区视网膜功能及厚度间的关系。

方法：选取NPDR患者20例35眼患眼为糖尿病视网膜病变(diabetic retinopathy,DR)组,行多焦视网膜电图(multifocal electronic retinography, mfERG)及Spectralis 相干断层扫描(Spectralis optical coherence tomography,Spectralis OCT)检查。以15例20眼正常眼为OCT对照组,以19例20眼正常眼为mfERG对照组,OCT对照组做Spectralis OCT检查,mfERG对照组做mfERG检查。

结果：与对照组相比,DR组黄斑中心凹mfERG1环的P1波反应密度减小,P1波及N1波隐含期改变无统计学意义; DR组无水肿的黄斑中心凹视网膜厚度、神经上皮层厚度仍有显著增加。

结论：应用mfERG可以在视网膜无可见明显结构改变之前发现视网膜功能上的异常变化; Spectralis OCT可以测量视网膜各层厚度,反映视网膜精细结构变化,验证视网膜功能上的异常改变,二者联合应用为极早期发现糖尿病视网膜病变视功能改变提供有效的证据,并为及时治疗提供资料。     

Ultrawide-field Fluorescein Angiography for Evaluation of Diabetic Retinopathy

Purpose

To investigate the advantages of ultrawide-field fluorescein angiography (FA) over the standard fundus examination in the evaluation of diabetic retinopathy (DR).

Methods

Ultrawide-field FAs were obtained in 118 eyes of 59 diabetic patients; 11 eyes with no DR, 71 eyes with nonproliferative diabetic retinopathy (NPDR), and 36 eyes with proliferative diabetic retinopathy (PDR), diagnosed by the standard method. The presence of peripheral abnormal lesions beyond the standard seven fields was examined.

Results

Ultrawide-field FA images demonstrated peripheral microaneurysms in six (54.5%) of 11 eyes with no DR and all eyes with moderate to severe NPDR and PDR. Peripheral retinal neovascularizations were detected in three (4.2%) of 71 eyes with NPDR and in 13 (36.1%) of 36 eyes with PDR. Peripheral vascular nonperfusion and vascular leakage were found in two-thirds of eyes with severe NPDR and PDR.

Conclusions

Ultrawide-field FA demonstrates peripheral lesions beyond standard fields, which can allow early detection and a close evaluation of DR.     

OCT及mfERG在DR早期及非增殖期中的应用

目的：用光学相干断层扫描（optical coherence tomo-graphy,OCT）测定糖尿病视网膜病变早期（non-diabetes retinopathy,NDR）及非增殖期（non-proliferative diabetes retinopathy,NPDR）的视网膜形态学改变及用多焦视网膜电图（multifocal electroretinogram,mfERG）测定其视网膜电活动的改变,评价不同分期糖尿病视网膜病变（diabetic retinopathy,DR）的严重程度。 方法：选取50~70岁的老年人30例30眼作为正常组,已确诊为2型糖尿病患者50例50眼做为实验组。分别在标准状态下行OCT及mfERG检查,并对结果进行统计学分析。 结果：对于NPDR的患者,视网膜形态的变化：视网膜黄斑区大部分神经上皮层变厚,说明对于糖尿病这个危险因素,视网膜的功能在不断的下降,视网膜黄斑区神经上皮层在NDR中变化并不明显而在NPDR明显变厚,说明黄斑区形态在糖尿病早期变化并不大,随着糖尿病的病情加重,形态发生了很大变化。电生理学改变：mfERG的P1波随着病情的加重,其反应密度逐渐下降,在NDR就明显减低,而在NPDR,下降更为明显,说明在黄斑区,视网膜形态改变前,电活动已经减弱,在形态发生变化后,电活动的下降更为明显。 结论：OCT联合mfERG测定黄斑区域的形态改变及电活动改变,两种检查手段在疾病的早期观察、随访和进一步治疗的选择上具有很高的应用价值。     

对糖尿病视网膜病变患者视网膜血管循环时间的观察

目的：观察不同分期糖尿病性视网膜病变(diabetic retinopathy,DR)视网膜动、静脉循环时间的差异性,分析各期DR视网膜血管循环时间的变化特点。

方法：收集2016-03/2017-03我院眼科确诊的DR患者60例60眼,其中轻中度非增殖期糖尿病视网膜病变(nonproliferative diabetic retinopathy,NPDR)组20例20眼、重度NPDR组20例20眼、增殖期糖尿病视网膜病变(proliferative diabetic retinopathy,PDR)组20例20眼。通过眼底荧光血管造影(undus fluorescein angiography,FFA)检查记录视网膜动脉4个分支主干刚开始显影即臂视网膜循环时间(A1)和完全充盈的时间(A2)、视网膜静脉4个分支主干全部出现层流的时间(V1)和完全充盈的时间(V2),并进行相关分析。

结果：视网膜动脉通过时间(A2-A1)三组比较,差异无统计学意义(F=1.642,P=0.157)。视网膜毛细血管通过时间(V1-A2)、视网膜静脉通过时间(V2-V1)、视网膜动静脉通过时间(V2-A1)三组分别比较,差异均有统计学意义(F=5.794、5.180、5.564,P=0.007、0.009、0.008),其中PDR组均较轻中度和重度NPDR组明显延长,重度NPDR组均较轻中度NPDR组明显延长。

结论： DR病程越长,程度越重,视网膜微血管破坏越严重,视网膜微循环时间越长。     

Early changes of retinal function in diabetic patients detected by multifocal electroretinogram

To investigate the early changes of retinal function in diabetic patients detected by multifocal electroretinogram (mfERG). ·METHODS: The first-order kernel responses of mfERG were recorded fromeyes of 33 normal control subjects, 63 diabetic patients without retinopathy and 43 diabetic patients with background retinopathy. The response densities and implicit times of N₁ and P₁ were compared among the control, diabetic patients without retinopathy and diabetic patients with retinopathy. ·RESULTS: The response densities of N1 and P1 in central 3 rings were reduced significantly in diabetic eyes with and without retinopathy. And the implicit times of N₁ and P₁ were delayed significantly only in diabetic eyes with retinopathy. ·CONCLUSION: mfERG can detect the early changes of retinal function quantitatively in diabetic patients. Analysis of response densities and implicit times of N₁ and P₁ can reflect the progress of local retinal dysfunction in diabetes     

PFCL and ILM peeling in macular hole with retinal detachment

To investigate the early changes of retinal function in diabetic patients detected by multifocal electroretinogram (mfERG). ·METHODS: The first-order kernel responses of mfERG were recorded fromeyes of 33 normal control subjects, 63 diabetic patients without retinopathy and 43 diabetic patients with background retinopathy. The response densities and implicit times of N₁ and P₁ were compared among the control, diabetic patients without retinopathy and diabetic patients with retinopathy. ·RESULTS: The response densities of N1 and P1 in central 3 rings were reduced significantly in diabetic eyes with and without retinopathy. And the implicit times of N₁ and P₁ were delayed significantly only in diabetic eyes with retinopathy. ·CONCLUSION: mfERG can detect the early changes of retinal function quantitatively in diabetic patients. Analysis of response densities and implicit times of N₁ and P₁ can reflect the progress of local retinal dysfunction in diabetes     

Comparison of mfERG waveform components and implicit time measurement techniques for detecting functional change in early diabetic eye disease

This study first compares two methods for measuring first order multifocal electroretinogram (mfERG) implicit time abnormalities in eyes with early diabetic retinopathy. Two analysis methods are used: template stretching (multiplicative scaling) of an 80 msec response epoch and template sliding (cross-correlation or additive scaling) of portions of responses containing the major waveform features. The study also compares the relative sensitivities of N1, P1 and N2 implicit time assessed by cross-correlation. The nature of the change in the mfERG waveform associated with diabetes is also assessed. MfERGs were recorded from 15 eyes of 15 individuals with diabetes and early non-proliferative retinopathy and 20 eyes of 20 healthy control subjects of similar age. Implicit time determined by template stretching is more frequently abnormal in the eyes of the diabetic subjects than the implicit time of any of the components assessed by template sliding. This is attributable to the lower variability of the template stretching implicit time measure in normals. Of the components, P1 is most often abnormal in the eyes of individuals with diabetes. Responses recorded from retinal areas with retinopathic signs are more often abnormal than those from other areas. Later components of the response are not delayed more than earlier ones. We conclude that template stretching is a sensitive measurement technique, but that it does not fully capture the effect of diabetes on the first order mfERG well.