笃斯越橘对兔眼光损伤前后视网膜电流图及组织结构的影响

目的 探讨笃斯越橘对兔眼光损伤前后视网膜电流图(ERG)及组织结构的影响.方法 对照实验研究.采用随机数字表法将35只青紫蓝兔分为5组,每组7只兔.各组自由进食、摄水,对A、D组兔加用笃斯越橘匀浆.4周后,在光镜下观察D、E组兔视网膜组织学结构变化并测量光感受器细胞外核层(ONL)厚度及凋亡指数(AI);按照国际临床视觉电生理学会标准化方案确立的最大混合反应ERG及振荡电位(Ops)对A、B、C组兔视网膜进行检测.随后进行光损伤照射.照射后A组停用笃斯越橘,C组加用笃斯越橘,B组保持不变.在光照后1 d、1和2周进行ERG检测.检测完毕,取A、B、C组兔视网膜进行组织学分析.对各组兔视网膜ERG潜伏期、振幅、ONL厚度及AI值比较采用双因素及单因素的方差分析,进一步两两比较采用LSD检验法.结果 (1)最大混合反应ERG检测结果:A组饲养4周后,潜伏期:a波(14.079±0.841)ms,b波(35.629±6.865)ms;振幅:a波(83.936±10.807)μV,b波(280.931±27.807)μV.A组光照2周后,潜伏期:a波(15.571±1.087)ms,b波(38.915±7.683)ms;振幅:a波(66.478±9.709)μV,b波(245.887±11.797)μV.B组饲养4周后,潜伏期:a波(15.635±1.661)ms,b波(42.985±3.164)ms;振幅:a波(69.331±12.355)μV,b波(197.331±16.157)μV.B组光照2周后,潜伏期:a波(18.783±1.966)ms,b波(52.322±4.784)ms;振幅:a波(57.562±8.217)μV,b波(159.569±17.859)μV.C组饲养4周后,潜伏期:a波(15.115±0.940)ms,b波(43.242±4.662)ms;振幅:a波(72.812±4.403)μV,b波(207.815±14.373)μV.C组光照2周后,潜伏期:a波(15.957±2.154)ms,b波(44.081±9.506)ms;振幅:a波(66.804±8.755)μV,b波(186.271±29.349)μV.A、B、C组间最大混合反应ERG在饲养4周后及光照2周后差异有统计学意义(潜伏期a波:饲养4周后F=6.057,P＜0.05;光照2周后F=13.296,P＜0.05.潜伏期b波:饲养4周后F=9.949,P＜0.05;光照2周后F=11.145,P＜0.05.振幅a波:饲养4周后F=8.468,P＜0.05;光照2周后F=4.844,P＜0.05.振幅b波:饲养4周后F=70.194,P＜0.05;光照2周后F=62.161,P＜0.05);3组间ΣOPs值振幅差异有统计学意义(饲养4周后F=17.482,P＜0.05;光照2周后F=11.748,P＜0.05).进一步两两比较,显示光照前最大混合反应ERG振幅B组的a、b波及C组的a、b波均低于笃斯越橘饲养4周后的A组(B组的a波、b波振幅与A组比较:P=0.003,0.000;C组的a波、b波振幅与A组比较:P=0.001,0.000);光照1 d、1和2周后,A组的振幅b波较同期B组均明显升高(均P=0.000);光照后随用药时间延长,C组ERG检测值逐渐改善;光照2周后,C组较B组的b波潜伏期缩短,振幅提高(潜伏期P=0.008,振幅P=0.007).(2)视网膜组织学观察结果:光照前在光镜下观察兔视网膜组织,D、E组兔视网膜结构形态正常,光感受器细胞内外节排列整齐规则.B组视网膜结构排列紊乱,有光感受器细胞外节碎解.A、C组视网膜结构改变介于D、E和B组之间.各组间ONL厚度差异有统计学意义(F=330.506,P＜0.05).(3)各组间AI值差异有统计学意义(F=230.126,P＜0.05);B组AI值为(10.960±1.534)%,较各组明显增高(均P=0.000);D组AI值为(1.817±0.203)%,小于E组(P=0.000).结论 笃斯越橘对于暴露于正常昼夜日光交替下的兔视网膜有减少细胞凋亡、减轻光化学损伤的作用;预防性地使用笃斯越橘能明显降低光损伤的程度;光损伤后应用笃斯越橘有助于视网膜组织的修复.     

超声微泡造影剂联合美金胺增强视神经损伤大鼠视网膜神经节细胞保护作用

目的 探讨超声微泡造影剂联合美金胺对视神经损伤大鼠视网膜神经节细胞( RGC)的保护作用.方法 将Sprague-Dawley(SD)雄性成年大鼠40只随机分为正常对照组(A组),假手术组(B组),空白对照组(C组),玻璃体腔单独注射美金胺组(D组),玻璃体腔注射美金胺加超声微泡组(E组)5个组,每组8只大鼠,再将各组随机分为视神经损伤后1、2周2个亚组,各亚组4只大鼠.A组不做任何处理;B组只暴露视神经,不进行钳夹,玻璃体腔注射生理盐水,立即用超声波辐照大鼠眼球;C～E组建立视神经钳夹伤模型后,处理方式分别为C组玻璃体腔注射生理盐水,D组玻璃体腔注射美金胺,E组玻璃体腔注射超声微泡造影剂及美金胺,立即用超声波辐照大鼠眼球.视神经损伤1、2周时,各组行逆行荧光金标记RGC并计数;闪光视觉诱发电位(F-VEP)检测,记录P100波潜伏期及振幅;荧光电子显微镜下观察视网膜细胞形态学改变.结果 逆行荧光金标记RGC结果显示,各处理组视网膜定向铺片上均可见金黄色着染的RGC.A、B组RGC数间差异无统计学意义(q=0.018,0.011;P=0.986,0.873);C～E组RGC数均较A组减少,差异具有统计学意义(F=85.944,P=0.012);D组RGC数多于C组,差异具有统计学意义(q=1.721,1.924;P=0.043,0.037);E组RGC数明显高于C、D组,差异具有统计学意义(q=1.128,1.482,P=0.027,0.008;q=1.453,1.855,P=0.031,0.010).F-VEP检测发现,A、B组P100波潜伏期及振幅间差异无统计学意义(q=0.008,0.019,P=0.981,0.946;q=0.072,0.052,P=0.737,0.851) ;C～E组P100波潜伏期较A组延长,振幅较A组降低,差异具有统计学意义(F=134.312,106.312;P=0.017,0.009).荧光电子显微镜下观察发现,A、B组大鼠视网膜各层结构完整,排列整齐,RGC排列紧密整齐,细胞核均匀深染,胞核大小一致.C～E组大鼠的视网膜不同程度水肿变厚,RGC有不同程度的排列紊乱,空泡化及细胞数目减少.结论 超声微泡造影剂联合美金胺能抑制视神经损伤后大鼠RGC的丢失,促进其视功能的恢复,对视神经损伤大鼠的RGC具有保护作用.     

外伤性前房积血的视觉电生理改变

目的探讨视觉电生理在外伤性前房积血中的应用价值.方法外伤性前房积血患者53例53眼.视力≥0.1为A组,视力＜0.1为B组;对侧健眼为各对照组.对所检测的闪光视网膜电图(flashelectroretinogram F-ERG)的a、b波和图形视觉诱发电位(pattern visual evoked potential P-VEP)P100波的振幅和潜伏期的结果进行统计学分析.结果受伤眼ERG的a、b波振幅与健眼比较都有明显下降(P＜0.005).A、B两组间比较,B组振幅下降更明显(P＜0.05),在B组a波下降幅度(P=0.003)较b波下降幅度(P=0.021)更大些.受伤眼ERG的a、b波潜伏期的变化仅在B组有轻度延长,与A组比较差异不明显(P=0.128).A、B两组的P-VEP P100波振幅下降,潜伏期延长,与对照组比较差异有显著性(P＜0.05),并且A、B两组间的振幅比较(P=0.023)以及潜伏期比较(P=0.027)差异均有显著性.结论视觉电生理可作为判断外伤性前房积血时视觉功能检查的客观方法之一.     

正常人视觉诱发电位的特征

目的:探讨正常人视觉诱发电位(visualevokedpotential,VEP)的特征,以获得正常参考值。方法:应用法国Metrovision公司生产的VisionMonitor视觉诱发系统对正常人60例(73眼)在白色、红色和蓝色闪光刺激下进行闪光VEP检查,按年龄不同分成4组:A组(5～14岁)19眼,B组(15～29岁)17眼,C组(30～49岁)21眼,D组(50～65岁)16眼;对正常人62例(77眼)在15,30和60min视角黑白棋盘格翻转图形刺激下进行图形VEP检查。按年龄不同分成4组:A组(5～14岁)20眼,B组(15～29岁)20眼,C组(30～49岁)22眼,D组(50～65岁)15眼。结果:在白色、红色、蓝色闪光刺激下P2波的潜伏期分别为122.2±8.3,122.5±11.7,124.1±8.5ms;在白光刺激下D组P2波的潜伏期与其他各年龄组相比,均有差异(P<0.05)。其他各年龄组相互比较,均无显著意义。在红光和蓝光刺激下A组与D组比较,A组、D组与其他年龄组比较均延长,有显著意义(P<0.05),其他各年龄组相互比较,均无显著意义。在15',30'和60'视角黑白棋盘格翻转图形刺激下P100波的潜伏期分别为111.6±6.0,105.9±5.3,105.1±3.8ms。各年龄组图形VEP相比较均无显著意义(P>0.05)。结论:在白色、红色和蓝色闪光刺激下14岁以下年龄组和50岁以上年龄组闪光VEPP2波的潜伏期较其他组延长,图形VEPP100波的潜伏期各年龄组比较无显著差异。     

血管内皮生长因子反义寡脱氧核苷酸联合血管生成素-1对糖尿病视网膜病变大鼠视网膜血管渗漏及新生血管生成的影响

目的 观察血管内皮生长因子(vascular endothelial growth factor,VEGF)反义寡脱氧核苷酸(ASODN)联合血管生成素-1(angiogenin-1,Ang-1)对糖尿病视网膜病变(diabetic retinopathy,DR)大鼠视网膜血管渗漏及新生血管生成的影响.方法 选取健康雄性SD大鼠60只,随机分为正常对照组(A组)5只和糖尿病组55只,糖尿病组通过链脲佐菌素腹腔注射诱导糖尿病模型成功后再饲养3个月行眼底荧光血管造影检查,确定DR大鼠模型且视网膜病变程度相仿的大鼠,随机抽取45只分为DR对照组(B组,5只)、PBS缓冲液对照组(C组,10只)、VEGF ASODN干预组(D组,10只)、Ang-1干预组(E组,10只)、联合干预组(F组,10只).C组玻璃体内注射PBS缓冲液5μL;D组玻璃体内注射浓度为100 μmol·L-1 VEGF ASODN 5 μL;E组玻璃体内注射浓度为160 mg·L-1Ang-1 5 μL;F组玻璃体内注射100 μmol·L-1 VEGF ASODN及160 mg·L-1 Ang-1各5μL;3 d后再次行上述操作.各组大鼠行眼底荧光血管造影检查,对比观察不同组别大鼠视网膜血管渗漏情况,病理组织切片光学显微镜下突破内界膜的观察视网膜新生血管芽细胞核数.结果 A、B、C、D、E和F组视网膜新生血管渗漏面积分别为0、( 20.98±1.14) mm2、(21.47±1.65) mm2、(14.60±1.55) mm2、(13.80 ±1.19) mm2、( 10.81±1.35) mm2;D、E、F组新生血管渗漏面积低于B、C组,差异有统计学意义(F=103.99,P ＜0.05);F组渗漏面积低于D、E组,差异有统计学意义(F=190.94,P＜0.05);B组与C组之间差异无统计学意义(t =0.22,P＞0.05).A、B、C、D、E和F组突破内界膜的新生血管芽细胞核数分别为(1.13±0.31)个、(80.31±5.21)个、(81.08 ±2.57)个、(37.37±3.41)个、(41.07±2.09)个、(14.41±1.23)个;D、E、F组突破内界膜的血管芽细胞核数均低于B、C组,差异有统计学意义(F=1339.41,P＜0.05);F组突破内界膜的血管芽细胞核数低于D、E组,差异有统计学意义(F =714.91,P ＜0.05);B组与C组之间差异无统计学意义(t=0.35,P＞0.05).结论 VEGFASODN联合Ang-1玻璃体内注射能明显抑DR大鼠视网膜新生血管的生成,减少视网膜血管渗漏.     

正常儿童多焦视觉诱发电位的特征

目的：分析正常儿童多焦视觉诱发电位（multifocalvisual evoked potential,mfVEP）的特征,为其临床应用提供正常参考值.方法：采用法国Vision Monitor视觉电生理检察系统对50例正常儿童66眼进行mfVEP检查,观察mfVEP的P1波和N2波振幅密度和潜伏期,分析性别、年龄、眼别对正常儿童mfVEP之P1波和N2波振幅密度和潜伏期的影响.结果：正常儿童mfVEP之P1波和N2波振幅密度在视野中央最大,随离心度的增加迅速减小;潜伏期在视野中央最小,一般随离心度的增加逐渐延长;性别与P1波的潜伏期有相关性（P=0.014）,与P1波的振幅密度及N2波的振幅密度和潜伏期没有相关性（P＞0.05）,而年龄、眼别与mfVEP之P1波和N2波的振幅密度和潜伏期无相关性（P＞0.05）.结论：正常儿童mfVEP具有一定特征,能够反映视野不同部位的视觉诱发反应,可为临床应用提供正常参考值.     

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。     

儿童远视性弱视眼调节幅度及调节灵活度的研究

目的　比较不同程度远视性弱视眼与正视眼之间调节幅度及调节灵活度的差别.方法　临床病例对照研究.对2009年1～12月在河北大学附属医院眼科门诊能配合检查的远视性弱视儿童50例92只眼,按弱视程度分为中度弱视组(A组),轻度弱视组(B组),弱视治愈组(C组).正常儿童组(对照组)20人40只眼,采用改良移近法测量调节幅度(AMP),正负球镜翻转测量调节灵活度.结果　A组、B组、C组及对照组AMP平均值分别为(13.07±1.72)D、(14.17±1.60)D、(15.55±1.26)D、(16.09±1.11)D,调节灵活度平均值分别为(5.77±2.00)次/分、(5.13±1.67)次/分、(5.06±1.56)次/分、(5.45±2.19)次/分,结果显示A组和B组AMP均分别显著低于C组及对照组(P＜0.05).C组与对照组差异无统计学意义(P =0.247).各组调节灵活度差异无统计学意义(P=0.723).A组及B组中AMP与矫正视力呈正相关(r=0.487,P=0.007),AMP与屈光度无显著相关性(r=-0.236,P=0.218).结论　与同年龄正常眼相比,远视性弱视儿童眼调节幅度降低,调节幅度与弱视程度有显著相关性.调节灵活度差异无统计学意义.     

儿童弱视的图形视觉诱发电位临床研究

目的探讨图形视觉诱发电位(P-VEP)在儿童弱视检查中的价值.方法随机选择95例(167眼)弱视儿童和36例正常儿童进行P-VEP检查.结果弱视眼P-VEP和N75和P100潜伏期比正常对照眼延长(P=0.012).振幅低于正常对照组(P=0.001).弱视眼与对侧健眼比较N75和P100振幅有明显下降(P=0.013,P=0.001),P100潜伏期有明显延长(P=0.001).弱视对侧健眼与正常对照眼比较P100潜伏期延长,振幅下降(P=0.005,P=0.01).结论P-VEP可作为进一步判断弱视视觉功能的检查手段.     

冻干人纤维蛋白黏合剂在围绝经期雌兔干眼的应用研究

目的 探究冻干人纤维蛋白黏合剂通过泪道栓塞的方式对围绝经期雌兔干眼症的预防和治疗效果.方法 选取72只经抗感染处理后剪除第三眼睑的雌兔,制作围绝经期雌兔干眼症模型,手术完成后将其随机分为6组(每组12只):术后无处理组(A组)、PBS预防组(B组)、冻干人纤维蛋白预防组(C组)、造模后无处理组(造模时间:术后2个月,D组)、PBS治疗组(E组)、冻干人纤维蛋白治疗组(F组),并于注射前及注射后2周、4周及6周行Schimer实验(SIT)检查、角膜荧光素(fiuorescein,FL)染色及角膜共聚焦显微镜检查.结果 D、E、F三组不同时间点间的FL评分和SIT值有一定差别(F=27.346、10.608,P=0.000、0.001);三组间FL评分和SIT值有一定差别(F=7.579、6.786,P=0.002、0.007);三组的FL评分和SIT值的变化趋势有明显差别(F=44.897、3.424,P=0.000、0.045).D组、E组、F组在处理2周、4周、6周后,F组FL评分和SIT值较D组明显好转,差异有统计学意义(t=2.906、3.654、4.504,P=0.022、0.017、0.013;t=4.573、5.759、7.231,P=0.032、0.019、0.008);E组、F组FL评分和SIT值在处理后相比,差异有统计学意义(t=2.776、4.124、5.324,P=0.032、0.026、0.017;t=1.969、3.122、4.324,P=0.038、0.023、0.009).A、B、C三组注射6周后上皮基底细胞(F=17.306,P=0.002)和炎症细胞密度(F=34.024,P=0.000)比较,D、E、F三组上皮基底细胞(F =3.749,P =0.042)和炎症细胞密度(F=8.806,P=0.005)比较,均有统计学差异.结论 通过冻干人纤维蛋白黏合剂进行泪道栓塞对于干眼症的预防和治疗均有显著疗效.     

Evaluation of methods for assessing visual function of infants.

PURPOSE: Commonly used behavioral and electrical testing methods for estimation of visual acuity and visual function in infants yield different estimates and may not accurately predict visual acuity and visual function in later life. Moreover, neither test-retest variability nor side-by-side comparisons of the various methods have been thoroughly evaluated in the same infant population. The purpose of this study was to provide such an evaluation. METHOD: The test-retest variability of visual acuity and visual function was evaluated for the Teller Acuity Card (TAC) procedure, sweep visual evoked potential (VEP), as well as latency and amplitude measured by transient pattern VEP. Groups of approximately 20 infants contributed test-retest data. Visual function estimated by the various methods in a larger group of infants (n = 118) was compared. Correlations between methods and the validity of the various methods to detect maturational changes between 4 and 8 months of age were also assessed. Administration of these tests was according to standard and usual procedures. RESULTS: The average percent difference between test and retest estimates of acuity as well as the SD was lowest for transient VEP latency (3%, 7% SD). The other methods were markedly more variable: sweep VEP (2%, 22% SD), TAC procedure (8%, 20% SD), and transient VEP amplitude (7.5%, 39% SD). Average coefficients of variation showed a similar trend: transient VEP latency, 8%; sweep VEP, 15%; TACs, 30%; and transient amplitude, 53%. Correlations among estimates by the methods were poor, but expected changes in visual maturation from 4 to 8 months of age were detected with all methods. CONCLUSIONS: All methods evaluated provide valid and reliable test-retest data for a group, but are less valid for estimating visual acuity and visual function of an individual subject. The poor correlations between any 2 of the testing methods suggest that each test assesses a different aspect of vision. Nonetheless, expected maturational changes between 4 and 8 months of age were readily detectable by all methods evaluated.     

Optic nerve functions and visual evoked potential after acute optic neuritis

目的:比较视神经炎患者和正常人的视神经功能与视觉诱发电位.方法:本研究为2011年9月至2013年2月在马来西亚大学眼科医院进行的横断面研究.研究包含在检查前3mo至2y间发生特发性神经炎一次的视神经炎患者20例和10例正常人.眼科检查包括视力、色觉、视觉灵敏度、视野和视觉诱发电位.独立t检验用于比较视神经炎组与对照组视神经功能和VEP参数的差异.在参数非正态分布时,Mann-Whitney试验用于比较两组间的中位数.结果:视神经炎组的平均年龄为30.8岁.在视神经炎发作至评估期间的平均持续时间为6.6个月.视神经炎组视力较差,平均LogMAR值(0.52)明显高于对照组(P=0.001).色觉下降,视神经炎组的平均值为63%(P=0.001).视神经炎患者的对比敏感度在四个空间频率上均有所下降 [3CPD(P=0.029),6CPD(P=0.026),12CPD(P=0.002)、18CPD(P=0.006)].视神经炎组的视野下降有统计学意义(P<0.001).与对照组相比,视神经炎组的VEP P100潜伏期有轻微延长.但使用棋盘格模式1或2时,VEP潜伏期的差异不显著.视神经炎患者的VEP振幅较高,但两组差异无统计学意义.结论:视神经炎急性发作,平均6mo后视神经功能(即视力、色觉、对比敏感度和视野)显著下降.视神经炎组和对照组的VEP振幅和潜伏期无显著差异.VEP可能不是理想的诊断视神经炎既往发作史的试验,尽管VEP参数在浮动后趋于正常.     

Normative values of visual evoked potential in adults

Purpose:Visual evoked potentials (VEP) are used to determine the function of visual pathway from the optic nerve to visual cortex. Various factors may affect VEP response, viz., technical and environmental. The aim of this study is to obtain the normative value of VEP latency and amplitude parameters in adulthood in Indonesia, as well as the relationship of height, weight, body mass index (BMI), head circumference, and visual acuity with the variety of latency and amplitude values of VEP parameters.Methods:It is a cross-sectional study on 120 healthy subjects consisting of 60 males and 60 females between 18 and 65 years old. Height, weight, BMI, head circumference, and visual acuity were measured and continued with VEP examination using a 26′ checkerboard pattern on the left and right eyes alternately. All data were collected and analyzed with the Shapiro–Wilk test using statistical software R version 3.5.2.Results:Mean value of P100 latency (interocular latency) of left and right eye were 104.6 ± 3.4 ms and 104.1 ± 3.4 ms, respectively, as well as 9.8 ± 4.7 μV and 10.3 ± 5.4 μV for the amplitude. There was no significant difference between the male and female group, as well as on the age group. Female significantly exhibited a higher P100 amplitude than male. The greater the age, the lower amplitude of P100 significantly.Conclusion:Gender and age do not affect the P100 latency value but only affect P100 amplitude. Height, weight, BMI, head circumference, and visual acuity also do not affect the P100 latency and amplitude.     

健康婴儿的闪光视觉诱发电位检查

目的：：评估健康婴儿的视觉诱发电位( VEP)。方法：选取34例神经系统及眼部均健康的、年龄为2~10月龄的婴儿,运用闪光VEP检查并比较双眼P3波潜伏期与振幅。结果：所有婴儿的P3波数据均被记录。其平均潜伏期为138~140ms,振幅为7~9μV。潜伏期不稳定。结论：病理状态下,婴儿的潜伏期或振幅可能不会出现变异。而由于视路和皮层的髓鞘发育会使其出现变异,应注意类似于P3波的皮层波或其他波出现。因此,使用闪光VEP检测年龄为1~3月龄的婴儿是不准确的。     

Electroencephalogram-based scaling of multifocal visual evoked potentials: effect on intersubject amplitude variability

PURPOSE: The interindividual variability of the visual evoked potential (VEP) has been recognized as a problem for interpretation of clinical results. This study examines whether VEP variability can be reduced by scaling responses according to underlying electroencephalogram (EEG) activity. METHODS: A multifocal objective perimeter provided different random check patterns to each of 58 points extending out to 32 degrees nasally. A multichannel VEP was recorded (bipolar occipital cross electrodes, 7 min/eye). One hundred normal subjects (age 58.9 +/- 10.7 years) were tested. The amplitude and inter-eye asymmetry coefficient for each point of the field was calculated. VEP signals were then normalized according to underlying EEG activity recorded using Fourier transform to quantify EEG levels. High alpha-rhythm and electrocardiogram contamination were removed before scaling. RESULTS: High intersubject variability was present in the multifocal VEP, with amplitude in women on average 33% larger than in men. The variability for all left eyes was 42.2% +/- 3.9%, for right eyes 41.7% +/- 4.4% (coefficient of variability [CV]). There was a strong correlation between EEG activity and the amplitude of the VEP (left eye, r = 0.83; P < 0.001; right eye, r = 0.82; P < 0.001). When this was used to normalize VEP results, the CVs dropped to 24.6% +/- 3.1% (P < 0.0001) and 24.0% +/- 3.2% (P < 0.0001), respectively. The gender difference was effectively removed. CONCLUSIONS: Using underlying EEG amplitudes to normalize an individual's VEP substantially reduces intersubject variability, including differences between men and women. This renders the use of a normal database more reliable when applying the multifocal VEP in the clinical detection of visual field changes.     

Visual function correlates with nerve fiber layer thickness in eyes affected by ocular hypertension.

PURPOSE: To test whether the high variability observed when measuring pattern electroretinogram (PERG), visual evoked potentials (VEP), and spatial contrast sensitivity (SCS) in eyes with ocular hypertension is associated with variation in nerve fiber layer thickness, as measured by optical coherence tomography (OCT). METHODS: The study involved 32 untreated eyes (32 patients; age range, 29-64 years) showing a normal whiteon-white 24/2 Humphrey (San Leandro, CA) perimetry, IOP between 23 and 28 mm Hg, best corrected acuity of 20/20 or better, and none of the following papillary signs on conventional color stereo slides: rim notch(es), peripapillary splinter hemorrhages, or increased vertical-to-horizontal cup-to-disc ratio. On recruitment, each eye underwent SCS testing, OCT, PERG, and VEP recordings. Linear regression (Pearson's test) or Spearman's rank regression was adopted for the analysis of the data. RESULTS: The 95% confidence limits of the electrophysiological data were: PERG P50 latency, 59.3 to 63 msec; PERG P50 to N95 amplitude, 0.74 to 1.15 cmV; VEP P100 latency, 113 to 118 msec; VEP N75 to P100 amplitude, 3.81 to 4.90 micromV. The 360 degrees nerve fiber layer thickness overall (NFLO) ranged between 113 and 169 microm (145+/-16 microm; mean+/-SD) and significantly correlated with PERG P50 to N95 amplitude (r: 0.518; P = 0.002), PERG P50 latency (r: -0.470; P = 0.007), VEP N75 to P100 amplitude (r: 0.460; P = 0.008), VEP P100 latency (r = -0.422; P = 0.016) and SCS at 3 cyc/deg (r: -0.358; P = 0.044). CONCLUSIONS: The variability of PERG, VEP, and SCS testing observed in eyes with ocular hypertension is associated with differences in NFL thickness (the thinner the layer, the worse the visual function).     

视路肿瘤三维适形放疗后视觉诱发电位的改变

目的观察累及视路的颅脑肿瘤在进行三维适形放疗后,视觉诱发电位(VEP)的变化。方法选取16累及视路的颅脑肿瘤患者,进行三维适形放疗,在放疗前、放疗结束、放疗后6、12个月进行VEP检查。结果放疗后、放疗后6、12个月VEP的P100波波幅及潜伏期与放疗前比较无显著的统计学差异(P>0.05)。结论三维适形放疗是一种较为安全有效的治疗颅脑肿瘤的方法,在杀灭肿瘤细胞的同时可以最大程度保护周围正常组织的功能。     

儿童Leber遗传性视神经病变VEP变化特点的临床分析

目的 分析不同病程、不同位点突变的Leber遗传性视神经病变（LHON）患儿视力及视觉诱发电位（VEP）的变化特点,并探讨两者之间的关系。设计回顾性病例系列。研究对象根据临床特点及基因检查确诊且病例资料完整的LHON患儿36例纳入研究,其中27例有完整的视力资料的患者纳入视力结果的分析。方法根据病程分为≤6个月的亚急性期组和>6个月慢性期组;根据致病基因位点分为11778位点突变组和14484位点突变组。分别比较不同发病时间、不同基因突变位点及不同性别间最佳矫正视力（BCVA）、视觉诱发电位（VEP）P100波平均潜伏期和振幅,并分析VEP指标与视力、发病时间的相关性。主要指标病程、BCVA、VEP P100波的潜伏期及振幅。结果36例LHON患儿,其中男性27例,平均年龄（10.75±4.64）岁。不同性别、病程、突变位点的最佳矫正视力均无统计学差异。亚急性期组VEP中P100波平均潜伏期（109.54±29.05）μs低于慢性期组（127.28±6.95）μs（t=-2.93,P=0.007）;两组间P100波振幅无明显差别。14484突变组BCVA、P100波平均潜伏期及振...     

Short-duration transient visual evoked potential for objective measurement of refractive errors

This study examined effects of uncorrected refractive errors (RE) in a short-duration transient visual evoked potential (SD t-VEP) system and investigated their role for objective measurement of RE. Refractive errors were induced by means of trial lenses in 35 emmetropic subjects. A synchronized single-channel EEG was recorded for emmetropia, and each simulated refractive state to generate 21 VEP responses for each subject. P100 amplitude (N75 trough to P100 peak) and latency were identified by an automated post-signal processing algorithm. Induced hypermetropia and myopia correlated strongly with both P100 amplitude and latency. To minimize the effect of baseline shift and waveform fluctuations, a VEP scoring system, based on software-derived P100 latency, amplitude and waveform quality, was used to estimate the RE. Using the VEP scores, a single VEP response had a high sensitivity and specificity for discerning emmetropia, small RE (<2 diopter) within a 2 diopter range and large RE (2–14 diopter) within a 4 diopter range. The VEP scoring system has a potential for objective screening of RE and for a more accurate 3-step objective refraction.     

Application of visual evoked potentials for preoperative estimation of visual function in eyes with dense cataract

PURPOSE: To determine whether the temporal frequency characteristics of the visual system as determined by visually evoked potentials (VEP) can be used for a preoperative estimation of the visual function in eyes with cataracts. METHODS: Light stimuli driven by a pseudorandom binary sequence (PRBS) of 40950 ms duration were presented and EEG recordings were made from 13 control and 20 patients with cataracts preoperatively and 1 week after cataract operation. The first kernel of the PRBS-VEP was obtained as the first-order cross-correlation function between PRBS and PRBS-VEP. The Fourier transform of this function was used as the temporal frequency characteristic (TFC). RESULTS: The mean +/- standard deviation of the latency and amplitude of the VEP in normal controls were 110.8+/-4.3 ms and 2.01+/-0.67 microV, respectively. A high correlation (r>0.7) between the pre-and postoperative VEP waveform was obtained in 13 eyes (65%), and 14 eyes (70%) in the VEP-TFC curves. The sensitivity of the examination was 73%, 27%, and 91% for the latency, amplitude and TFC of the VEP, respectively. The specificity of the examination was 67%, 100%, and 89% for the same measures. Eleven of 12 eyes with abnormal TFC preoperatively showed retinal or optic nerve lesions postoperatively. False-negative results were seen in cases with delayed corneal edema. CONCLUSION: Postoperative visual function of patients with cataracts can be predicted by preoperative measurement of the TFC obtained by PRBS-VEP.