弱视儿童多焦视觉诱发电位的分析

目的分析儿童多焦视觉诱发电位的变化,探讨弱视眼视野各部位视功能的损害。方法采用多焦视觉电生理仪检查54只弱视眼,并与48只正常眼结果比较。结果弱视眼mfVEP振幅密度的下降和潜伏期的延长在中央视野较显著,在周边部分无明显差异。弱视程度与振幅密度及潜伏期之间存在相关性。结论儿童弱视眼在视野中央部分视功能下降较显著。     

斜视性弱视多焦视觉诱发电位的研究

目的 研究斜视性弱视患者多焦视觉诱发电位(mfVEP)的特征性变化,探讨弱视的发病机制,对弱视预后的判断给予临床指导.方法 收集斜视性(内斜)弱视患者30例、正常人30例,分为斜视性弱视组、对侧眼组和正常对照组3组,采用多焦电生理系统进行图形mfVEP检测,分析潜伏期与振幅密度.结果 6个离心度上弱视组反应振幅密度较对侧组和正常组均显著降低.弱视组及对侧组的鼻侧视网膜反应振幅密度均低于颞侧视网膜,潜伏期延长.斜视性弱视患者斜视度与弱视眼视力及mfVEP波形异常程度之间均无明显相关性.结论 斜视性弱视患者mfVEP表明弱视患者的视皮层与视觉传导通路均存在损害,mfVEP检查可为弱视的诊断、治疗及预后判断提供客观依据.     

屈光参差性弱视的多焦视觉诱发电位

目的 研究屈光参差性弱视患者弱视眼与对侧眼的多焦视觉诱发电位(multifocal visual evoked potential,mVEP)的特征性变化.方法 采用美国EDI公司生产的VERIS SciencTM 4.2多焦电生理系统对31例屈光参差性弱视患者、30例正常人双眼分别进行图形mVEP检测,以潜伏期和振幅为分析指标,进行屈光参差性弱视眼、对侧眼和正常对照眼三组mVEP的对比研究.结果 在六个离心度上,弱视眼反应振幅密度较其对侧眼和正常眼均显著降低,潜伏期延长(P＜0.01).在六个离心度上弱视眼mVEP的波形异常程度均与弱视眼视力呈负相关(P＜0.05),而与屈光参差度之间均无明显相关性(P＞0.05).结论 屈光参差性弱视患者mVEP具有特征性改变,表明弱视患者的视皮层与视觉传导通路均存在损害,中心区损害重于周边区,mVEP波形的异常在一定程度上能够反映出弱视患者视力的异常程度.mVEP检查可为弱视的诊断、治疗和预后判断提供客观依据.     

多焦电生理客观检测青光眼视功能损害的意义

多焦电生理是近十几年发展起来的新技术，它分为多焦视网膜电图(mfERG)和多焦视觉诱发电位(mfVEP)两种。mfERG可以分别了解视网膜内层和外层对应于视野各部位的视功能。青光眼对视网膜造成的损害主要是视神经纤维层。本文介绍青光眼患者mfERG的波形改变，着重探索mfERG波形中可能所含的视神经纤维层成分，并探讨了mfERG在诊断青光眼中的局限性。mfVEP作为客观视野检查法近几年也在青光眼的视功能检查中得到一定的重视，本文介绍了mfVEP在青光眼患者中的波形改变与视野改变的对应性．以及mfVEP两眼不对称性在青光眼早期诊断中的意义。     

斜视性弱视儿童多焦视觉诱发电位的研究

目的:研究斜视性弱视多焦视觉诱发电位特征,探讨弱视发病机制。方法:采用德国Roland公司的RETIscan3.15多焦视觉电生理仪,记录和分析了斜视性弱视儿童80眼,外斜43眼内斜37眼,并与正常对照组儿童60眼作比较。结果:弱视眼N1-P1波振幅密度平均值和P1-N2波振幅平均值较正常组儿童在中央视野有下降,随离心度增加,这种现象呈下降趋势。P1波潜伏期平均值无明显异常。正常组和各斜视性弱视组N1-P1波振幅密度平均值:颞侧<鼻侧,P1波潜伏期平均值:颞侧>鼻侧。结论:斜视性弱视mfVEP中心区损害重于周边区,波形异常程度与弱视程度无关。内斜性弱视波形异常程度大于外斜性弱视。     

已治愈的单眼弱视患者多焦视觉诱发电位特征的研究

目的评估治愈的单眼弱视患者多焦视觉诱发电位(multifocal visual evoked potential,mfVEP)的恢复情况。方法 记录15例被治愈的单眼弱视(斜视性弱视、屈光参差性弱视或斜视性弱视合并屈光参差性弱视)患者及15例正常人的mfVEP,分别比较已治愈单眼弱视患者弱视眼、对侧眼及正常眼3组之间mfVEP特征峰P波平均潜伏期及振幅密度。结果 弱视眼特征峰P波平均潜伏期及振幅密度与对侧眼相比,差异均无统计学意义(均为P>0.05);弱视眼和对侧眼的特征峰P波平均潜伏期1环、2环、3环、4环均较正常眼显著延长,差异均有统计学意义(均为P<0.05),而平均振幅密度与正常眼比较,差异均无统计学意义(均为P>0.05)。结论 治愈的单眼弱视患者的弱视眼和对侧眼mfVEP特征峰潜伏期仍较正常人延长,说明仍存在视觉神经传导通路和视皮层的异常。     

黄斑病变的多焦视觉诱发电位检测

目的记录几种类型黄斑病变的多焦视觉诱发电位(mfVEP)变化，探讨mfVEP测试黄斑病变视功能变化的可行性。方法采用VERIS多焦视觉电生理仪测量31只黄斑病变眼和32只正常对照眼的mfVEP，将测试野分为上下两半，再分别由内向外分为3个环。两组对比分析每环mfVEP的二阶一次反应。结果黄斑病变眼上下半视野的中央环mfVEP的P1波潜伏期延长，N1-P1及P1-N2振幅降低，以下半视野的改变更为明显。结论mfVEP可以检测出黄斑病变的视功能损害。     

视网膜脱离高危眼中高度近视眼多焦视网膜电图和传统视觉电生理改变

目的观察视网膜脱离高危眼中的高度近视眼的视觉电生理改变,了解视功能损害程度。方法回顾我院门诊高度近视患者24例48眼,分别与高度近视伴对侧视网膜脱离20眼、正常人48眼对照组进行传统视觉电生理F-ERG、F-VEP、M-ERG(一阶反应,first order kernel,FOK)联合检测。结果与正常人对照组相比,高度近视的各项F-ERGa、b波表现为振幅下降明显(P<0.05),同时潜伏期下降(P<0.05),F-VEP P100改变无明显差异(P>0.05);但高度近视的各项F-ERGa、b波振幅下降程度没有高度近视伴对侧视网膜脱离眼明显(P<0.05),F-VEP P100与高度近视伴对侧视网膜脱离眼相比无明显改变(P<0.05)。M-ERG高度近视眼1~6环中心凹振幅密度下降、a,b波振幅下降介于对侧视网膜脱离眼和正常人眼之间(P<0.05),高度近视眼b波潜伏期延长在3~6环介于对侧视网膜脱离眼和正常人眼之间(P<0.05)。结论联合应用传统视觉电生理、M-ERG,为观察视网膜脱离高危眼的高度近视视功能受损提供了敏感客观依据,能定量、定性评价黄斑部后极部视网膜、视神经功能。     

《临床多焦视觉电生理学》出版

本书由广州中山眼科中心吴乐正教授主编，北京科学技术出版社出版。全书系统介绍了视网膜及视路生物电的产生及传播，多焦电生理技术测定原理、方法、影响因素及结果分析，以及此技术在眼黄斑病变、视网膜病变、视路病变等的应用。本书受国家科技学术著作出版基金资助，是国际上此领域的第一本学术专著。     

儿童屈光参差性弱视多焦视觉诱发电位初步研究

P波的潜时、振幅差异均无统计学意义(P＞0.05).(4)弱视的分度与双眼屈光参差度数差之间的相关系数为0.368(P＜0.05).结论 (1)屈光参差性弱视存在"单眼抑制".(2)屈光参差性弱视的机能及形态学异常可能存在于从神经节细胞到视皮层的整个通路中.(3)屈光参差性弱视的发病机制与其他类型弱视不同.(4)屈光参差性弱视程度与屈光度有一定的正相关.     

弱视的临床视觉电生理研究进展及其评述

近年来视觉电生理技术广泛地应用于弱视的临床研究,取得了丰富的成果。本文结合近年来弱视的临床视觉电生理研究进展,分别对于眼电图、视网膜电图、视觉诱发电位等视觉电生理指标的定义、产生机制及其在弱视的临床电生理研究中的意义等进行综述,并对相关研究结论的争议做一评述。     

屈光参差性弱视mfVEP的临床分析

目的分析屈光参差性弱视患者多焦视觉诱发电位(mfVEP)的特征性变化,以探讨弱视发病的可能机制。方法采用VERISScienceTM4.2多焦电生理系统对23例屈光参差性弱视患者、30例正常人进行双眼图形mfVEP检查,以潜伏期与振幅为分析指标,进行了屈光参差性弱视眼、对侧眼和正常对照三组mfVEP的对比研究。结果在六个离心度上弱视眼反应振幅密度较其对侧眼和正常眼均显著降低,潜伏期延长。弱视眼波形异常程度随离心度增加而减小,在六个离心度上弱视眼mfVEP的波形异常程度都与弱视眼的视力异常程度有相关性。结论屈光参差性弱视患者的mfVEP具有明显的特征性改变,表明弱视患者的视觉传导通路存在明显损害,在中心区损害重于周边区,弱视眼波形异常程度与视力异常程度有明显的相关性,mfVEP检查对于弱视的诊断、治疗和预后判断具有一定的指导意义。     

斜视性弱视眼的多焦视诱发电位特征

目的研究斜视性弱视眼视野各部位视功能的变化.方法记录和分析了5例斜视性弱视眼和45例正常对照眼的多焦VEP.刺激图形由61个六边形单元组成,每个刺激单元内有黑白格子,刺激野直径约13.6°.在VERIS系统电脑程序(伪随机双极m序列)控制下,各刺激单元同时并互相独立地进行黑白翻转刺激,通过用快速Walsh变换计算刺激与反应的互相关函数,分离提取到各自的反应波形.结果斜视性(内斜)弱视眼在中央视野和颞侧视野,多焦VEP潜伏期延长、振幅下降.按不同离心度的环分组统计,斜视性弱视眼与正常对照眼比较,P1波潜伏期平均值在中央凹和第一环分别延长20.2ms和11.2ms;P1-N2振幅平均值在中央凹下降68.8%,在第一环下降52.6%,在第二环下降47.5%,N1-P1振幅平均值在中央凹下降54.4%.按鼻颞侧分组统计,斜视性弱视眼与正常对照眼比较,潜伏期平均值在颞侧视野延长10.6ms;P1-N2振幅平均值在颞侧下降66.5%,N1-P1振幅平均值在颞侧下降63.7%.斜视性弱视眼潜伏期平均值在颞侧视野比在鼻侧视野延长11.2ms;P1-N2振幅平均值在颞侧视野比在鼻侧视野下降64.2%,N1-P1振幅平均值在颞侧视野比在鼻侧视野下降64.2%.结论本研究证实,斜视性(内斜)弱视眼在中央视野和颞侧视野,视功能下降较显著.     

儿童外斜视手术前后多焦视觉诱发电位的变化

目的　研究儿童外斜视手术前后多焦视觉诱发电位（ｍｕｌｔｉｆｏｃａｌｖｉｓｕａｌｅｖｏｋｅｄｐｏ-ｔｅｎｔｉａｌ,ｍＶＥＰ）特征峰的变化。方法　采用德国Ｒｏｌａｎｄ多焦视觉电生理仪,对２０例外斜视力正常组和６０例外斜伴不同程度（轻度、中度、重度）弱视组患者进行ｍＶＥＰ的检测,并进行视网膜不同区域的斜视矫正术术前及术后１个月、３个月、６个月的比较。结果　外斜伴轻、中度弱视患者的ｍＶＥＰ特征峰振幅反应密度在第一、二、三环术后与术前相比均升高,术后３个月、６个月与术前相比差异均有统计学意义（均为Ｐ＜０．０５）。外斜伴轻、中度弱视组上下半侧视网膜的ｍＶＥＰ特征峰的振幅反应密度较术前提高,差异均有统计学意义（均为Ｐ＜０．０５）;潜伏期缩短,但差异均无统计学意义（均为Ｐ＞０．０５）。外斜伴中、重度弱视患者术后各组鼻侧视网膜ｍＶＥＰ特征峰的振幅反应密度与颞侧相比差异均有统计学意义（均为Ｐ＜０．０５）。结论　外斜伴弱视患者鼻颞侧视网膜的视觉传导通路均有不同程度损害,且鼻侧视网膜的视觉传导通路损害均重于颞侧视网膜。外斜伴轻度弱视患者术后ｍＶＥＰ特征峰振幅反应密度可有不同程度提高,提高程度鼻侧视网膜要高于颞侧,鼻颞侧视网膜特征峰振幅反应密度达到平衡;外斜伴中、重度患者术后鼻侧与颞侧视网膜特征峰振幅反应密度提高程度相近,鼻颞侧视网膜特征峰振幅反应密度仍未达到平衡。     

Determining abnormal interocular latencies of multifocal visual evoked potentials

Purpose: To describe methods for measuring interocular latency differences of multifocal visual evoked potentials (mfVEP) and for determining regions with abnormal interocular latencies in patients. Methods: The mfVEPs from 100 individuals with normal visual fields and normal fundus examinations were analyzed. Individuals ranged in age from 21.6 to 92.4 years. The stimulus was a 60 sector, pattern-reversing dartboard display. Each sector had 16 checks, 8 white (200 cd/m²) and 8 black (<1 cd/m²). Interocular latency was measured as the temporal shift producing the best cross-correlation value between the corresponding responses of each eye. The corrected interocular latency was defined as the difference between this shift and the mean interocular latency (shift) for a particular sector and recording channel. Results: The variability of the corrected interocular latency decreased as the signal-to-noise ratio (SNR) of the mfVEP responses increased. For example, the 95% confidence intervals decreased from over 16 ms to under 4 ms as SNR increased. Grouping and summing the responses also lead to an increase in SNR and a decrease in the confidence interval. The results of various cluster criteria were also derived. A cluster criterion (e.g. two or more contiguous points within a hemisphere exceeding a given confidence interval), can serve to increase the specificity for detection of eyes or individuals with abnormal interocular latencies. For example, while 21% of the eyes had 3 or more points exceeding the 5% confidence interval, only 1.8% of the eyes had a cluster of 3 or more of these points. Finally, interocular latency was only weakly correlated with age (r=0.26). Conclusion: In testing for abnormalities in interocular latencies, the confidence interval should be based upon the SNR of the response. Grouping and summing responses to increase SNR or employing a cluster test may also prove useful.     

Application of multifocal visual evoked potentials in the assessment of visual dysfunction in macular diseases

Purpose

To evaluate the use of AccuMap multifocal visual evoked potentials (mfVEP) in visual dysfunction caused by macular diseases.

Methods

Forty-eight eyes with known macular diseases underwent AccuMap mfVEP and microperimetry 1 (MP1) assessments. Evaluation of mfVEP abnormality was based on an amplitude deviation probability plot and the AccuMap Severity Index (ASI). Correlation analyses of the mean mfVEP amplitude corresponding to a radius of 2°, 5°, and 10° of the central visual field, minimum angle of resolution best-corrected visual acuity (BCVA), and MP1 mean sensitivity of the corresponding areas were performed.

Results

Among the 48 affected eyes, AccuMap mfVEP detected an abnormality of the central visual field in 45 eyes, with a sensitivity of 93.8%. The mean mfVEP amplitudes within a radius of 2°, 5°, and 10° of the central visual field were found to be positively correlated with BCVA (P<0.01 for all groups). The mean amplitudes also positively correlated with the MP1 mean sensitivity value of the corresponding visual field (P<0.01 for all groups). In the group with stable fixation or predominantly central fixation, the mean mfVEP amplitudes did not correlate with the BCVA or the MP1 mean sensitivity value. Regardless of the fixation status, the ASI was found to correlate with both the BCVA and the total MP1 mean defect value.

Conclusion

Objective perimetry using AccuMap mfVEP might be applied in the assessment of macular function, with the ASI offering a potentially useful indicator for evaluating macular dysfunction.     

Determining abnormal latencies of multifocal visual evoked potentials: a monocular analysis

Purpose: To describe a methodology for measuring abnormal timing of monocular multifocal visual evoked potentials (mfVEP). Methods: The mfVEPs from 100 individuals with normal visual fields and normal fundus exams were analyzed. The stimulus was a 60 sector, pattern-reversing dartboard display. For each of the 60 locations of the dartboard and each channel and each eye, a template was derived based upon the average of the responses from the 100 normal individuals. In deriving this template, care was taken to exclude those responses reversed in polarity as compared to the average response. The best array of responses for each individual was compared to these templates. The relative latency of each response was measured as the temporal shift producing the best cross-correlation value. Results: The 95% confidence interval (CI) decreased as the signal-to-noise ratio (SNR) of the mfVEP responses increased. For example, the 95% CI decreased from over 17ms to under 9 ms as the SNR increased. Grouping and summing the responses also lead to an increase in SNR and a decrease in CI. Because the number of points exceeding the CI is not randomly distributed among normal individuals, a cluster criterion (e.g. two or more contiguous points within a hemisphere exceeding a given confidence interval) can be helpful. For example, while 18% of the eyes had 5 or more points exceeding the 5% confidence interval, only 6.5% of the eyes had a cluster of 5 of these points. The correlation between relative latency and age was relatively low (r=0.46). Conclusion: For detecting abnormalities in the timing of monocular, mfVEP responses, a template method provides a reasonable approach. In devising a particular test for abnormal timing, the CI should be based upon the SNR of the response. In addition, grouping and summing responses to increase SNR or employing a cluster test may also prove useful.