屈光参差性弱视眼的多焦视觉诱发电位特征

目的 研究屈光参差性弱视眼的多焦(多刺激野)视觉诱发电位(multifocal visual evoked potentials,MVEP)在视野各部位的特征,了解弱视眼视野各部位的视功能。 方法 检测32只屈光参差性弱视眼和31只正常对照眼视野中央8.6°的MVEP。 结果 在屈光参差性弱视眼,MVEP的潜伏期延长和振幅下降在视野中央较显著,这种改变随着离心度的增加而减少。 结论 屈光参差性弱视眼视野中央视功能下降较显著。 (中华眼底病杂志,2000,16:27-29)     

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.     

不同类型弱视儿童视网膜结构和视觉诱发电位及立体视功能的差异性分析

目的:分析不同类型弱视儿童的视网膜结构和功能、视觉诱发电位及立体视功能的差异性。方法:选取2014-05/2018-05在我院眼科治疗的中度弱视儿童92例136眼为观察组(屈光参差性31例31眼,屈光不正性35例70眼,斜视性26例35眼),另选取在我院眼科检查视力正常的儿童29例58眼为对照组。采用光学相干断层扫描(OCT)成像仪检测黄斑中心凹厚度、视盘周围及各象限视网膜神经纤维层(RNFL)厚度,采用视觉眼电图检测视网膜功能变化,观察视觉诱发电位P100波幅值及潜伏期的特点,并进行立体视觉检查。结果:屈光参差性、屈光不正性弱视儿童黄斑中心凹厚度、视盘周围及各象限RNFL厚度均明显高于对照组和斜视性弱视儿童(P<0.01)。与对照组相比,屈光参差性弱视儿童视觉眼电图光峰电位偏低,光峰时间延长,屈光不正性弱视儿童中近视儿童暗谷电位偏高,Arden比和Gliern比减小(均P<0.01)。三种类型弱视儿童视觉诱发电位P100波幅值均明显低于对照组,且1°和15′空间频率潜伏期明显延迟(均P<0.01)。屈光不正性弱视儿童交叉视差、非交叉视差、近零视差、远立体视功能正常眼数显著高于斜视性弱视儿童(P<0.0167),但与屈光参差性弱视儿童上述各项指标无差异。结论:屈光参差性弱视、屈光不正性弱视儿童视网膜结构存在明显异常,且P100波潜伏期延迟;斜视性弱视对立体视功能影响最大,而屈光不正性弱视影响最小。     

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.     

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。     

弱视患儿治疗前后立体视觉及P-VEP的研究

目的：探讨弱视儿童治疗前后立体视觉及P-VEP的变化。

方法：在我院门诊确诊的弱视儿童41例68眼,其中男17例29眼,女24 例39眼,年龄4～16(平均8.29±3.05)岁,按照弱视类型分为斜视性弱视组4例7眼,屈光参差性弱视组11例11眼,屈光不正性弱视组26例50眼。弱视治疗内容包括激光治疗、CAM训练、红光闪烁、立体视训练、电脑中频脉冲治疗。治疗前后分别对患者进行裸眼视力、最佳矫正视力、图形视觉诱发电位(pattern visual evoked potential, P-VEP)、同时视、融合视及立体视检测。

结果：弱视患儿治疗前,同时视、融合视、立体视的异常率分别为51.2%,51.2%,80.5%,其中以立体视受损最为常见。弱视治疗后,视力增进2行或2行以上者21眼(31%),基本治愈43眼(63%),无效4眼(6%),总有效率为94%。屈光不正性弱视疗效优于斜视性弱视或屈光参差性弱视。同时视、融合视、立体视功能正常者比例均增高。图形视觉诱发电位中P100波潜伏期缩短(P<0.05)。

结论：弱视患儿经积极的弱视治疗后,患儿的视力及立体视觉均可得到提高,P100波潜伏期缩短。     

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。     

4D数字化弱视斜视矫治系统对远视性屈光不正性及屈光参差性弱视的疗效观察

目的:评估4D数字化弱视斜视矫治系统对远视性屈光不正性及远视性屈光参差性弱视儿童的疗效。方法:招募3~9岁远视性屈光不正性及远视性屈光参差性弱视患者48例(其中远视性屈光不正性弱视18例36眼,远视性屈光参差性弱视30例30眼),所有患者排除其他眼病,在屈光矫正、合理遮盖的基础上接受4D数字化弱视斜视矫治系统的训练。初期训练以提高视力为主,视力达0.6以上者加上脱抑制训练及双眼视功能训练。比较训练前、后的视力及双眼立体视变化情况。结果:远视性屈光不正性弱视患者共18例36眼,其中轻度弱视组13眼,中度弱视组19眼,重度弱视组4眼。远视性屈光参差性弱视患者共30例30眼,根据弱视程度分为轻度弱视组5眼,中度弱视组13眼,重度弱视组12眼。治疗60次后视力均有明显提高。治疗60次后立体视有明显提高,且与屈光度无关(P>0.05),与初始视力及治疗后视力均呈正相关(P<0.05),与屈光参差量呈正相关(P<0.05)。结论:4D数字化弱视斜视矫治系统联合传统的弱视治疗方法能有效提高3~9岁远视性屈光不正性弱视和远视性屈光参差性弱视儿童的视力并改善其双眼视功能。     

屈光性弱视与屈光参差性弱视对比敏感度变化的比较

目的：观察屈光不正性弱视与屈光参差性弱视的对比敏感度改变的差异性。方法：对30例（56只眼）屈光不正性和26例（26只眼）屈光参差性弱视的视觉对比敏感度（CS）进行测定。结果：在明视状态下中、重屈光参差性弱视在中频（6c/d)区CS下降幅度大于屈光不正性弱视（P＜0.05);夜视条件下,两弱视组所有空间频率的CS均无显著性差异。结论：中、重度的屈光参差性弱视的视觉质量比屈光不正性弱视低下。     

儿童弱视与屈光不正

本文名分析了3099例2.5～14岁儿童的屈光状态.资料表明:非斜视者的屈光不正随着年龄增长,远视的发生和程度逐渐减少而近视的发生和程度逐渐增加。双眼屈光不正性弱视者,中、量度弱视的高、中度远视和近视比轻度弱视者多.单跟屈光不正性弱视者,高、中度远视和高度近视比非弱视眼的多.双眼内斜视性弱视的不同年龄和不同程度弱视的屈光分布无显著差异.单眼斜视性弱视的屈光分布与非弱视眼比,无显著差异.本文结果揭示屈光不正性弱视与高度屈光不正有关;眼位偏斜可能为斜视性弱视的主要原因.     

Variation of the Multifocal Visual Evoked Potential with Eccentricity in Isometropic Amblyopes

Purpose: To investigate the variation of visual function in different eccentricities of the visual field in isometropic amblyopes.Method: The stimulus matrix containing 61 hexagons was generated on a monitor. The diameter of the entire stimulating field was approximately 13.6 deg of arc; the frame rate of the monitor was 67 Hz. Every hexagon of the display contained a number of black and white small hexagonal patches which reversed during stimulation. These hexagons were simultaneously but independently modulated in time by the controlling computer program. The flashed elements were selected differently on each frame according to a computer-generated binary pseudo-random time series (m-sequence); the response contributions from each of the individual stimulus elements could be extracted from the cross corre-ation function. Subjects were asked to maintain fixation at the center of the stimulus pattern while each of the hexagons of the display reversed. The VERB system extracted the local responses by cro     

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。     

Asymmetries of optokinetic nystagmus in amblyopia: the effect of selected retinal stimulation

Open loop optokinetic eye movements were measured in response to monocular nasalward and temporalward visual field movement presented at four selected retinal sites in 6 strabismic amblyopes and 4 normal observers. Stimulus sites included the central retina (10 X 10 deg), a large field (40 X 32 deg), a large peripheral field with the center (10 X 10 deg) blocked out and a hemiretinal field (15 X 32 deg) excluding the fovea. We found directional preferences of OKN in amblyopia to nasalward stimulus movement for the foveal and concentric peripheral stimuli. The results of peripheral hemiretinal optokinetic stimulation of amblyopic subjects revealed a deficient OKN slow phase response from the temporal hemiretina, particularly for temporalward stimulus movement. There was no marked asymmetry of OKN in the normal group for the concentric stimuli. A normal preference was found for nasalward and temporalward stimulus field movement imaged on the nasal and temporal hemiretinae respectively. These results are interpreted in terms of a model of cortical and subcortical pathways for OKN derived from comparative studies of cat and monkey.     

Hemiretinal differences in speed of light detection in esotropic amblyopes

Nine esotropic amblyopes were tested monocularly in a simple reaction time (RT) paradigm with brief suprathreshold flashes of light presented at various eccentricities along the horizontal meridian of the nasal or temporal hemiretinae. All were clinically amblyopic in one eye only. RT was significantly longer in the amblyopic than in the other eye at 1, 5 and 10 deg but not at 25 and 35 deg from the fovea. Another clearcut finding concerned hemiretinal differences: in the non-amblyopic eye, as in control subjects, RT was faster in the nasal than in the temporal hemiretina and such a difference increased with the eccentricity of stimulus presentation. In the amblyopic eye, however, the only significant hemiretinal effect was at 10 deg with a temporal retina advantage and at 35 deg with a nasal retinal advantage. Furthermore, unlike in normal control subjects and the non-amblyopic eye of our esotropes, in the amblyopic eye there was no increase in RT with the eccentricity of stimulus presentation, except for the most peripheral visual field positions. It can be concluded that esotropic amblyopia affects the speed of suprathreshold light detection in the most central 10 deg of visual field and that the nasal hemiretina is clearly more impaired than the temporal hemiretina.     

Binocular summation in the fovea and peripheral field of anisometropic amblyopes

PURPOSE. Binocular performance in the central and peripheral visual fields was compared for normal and anisometropic amblyopes. METHODS. Binocular and monocular thresholds to a light detection task were measured along the four principal meridia in 10 young normal subjects and 10 anisometropic amblyopes using the Humphrey's Visual Field Analyser. Thresholds were obtained at the fovea and at retinal eccentricities of 5 masculine, 10 masculine, 15 masculine, 25 masculine, 40 masculine and 55 masculine on the horizontal, vertical and oblique meridia of 45 masculine and 135 masculine. RESULTS. Binocular summation ratios (binocular sensitivity/ 'best' monocular sensitivity) were calculated for all the eccentricities. In the normal group, the mean binocular summation ratio for the fovea and the peripheral field was not significantly different. In the amblyopic group, subjects showed no or minimal binocular summation in the foveal region but reached normal ratios in the periphery. DISCUSSION. Results are discussed in terms of tolerance to interocular sensitivity differences in the periphery and selective losses in cortical cells.     

Rarebit fovea test in children: reference data for children aged six to 10 years

Introduction: The most common way to examine vision is to measure visual acuity using letter charts. The Rarebit fovea test was developed for detection of small defects of foveal function at a stage before they cause abnormal visual acuity. In a recent study, the RFT was well tolerated in a smaller group of children between seven and nine years of age; however, the number of subjects in that study was small for the determination of reference values, and therefore the aim of the present study was to establish reference values for a larger group of children aged between six and 10 years and to evaluate the learning effect after repeated tests. Methods: Rarebit fovea test data were collected from a group of 108 subjects aged between six and 10 years as part of a screening program at a compulsory school in Stockholm, Sweden. All subjects had good visual acuity and minor refractive errors. They underwent two Rarebit fovea test examinations on one occasion. Results: Rarebit fovea test results ranged from a median mean hit rate of 94.0 to 97.5 per cent for pre‐school and third‐year children, respectively. For the entire group of children the median mean hit rate was 96 per cent (range 57 to 100). The third‐year children performed significantly better than the pre‐school (p < 0.01) and first‐year children (p < 0.05). A significant improvement from the first to second test run was noticed in all groups. Conclusion: The Rarebit fovea test proved to be well tolerated among children in a group of six to 10 year olds and more than 90 per cent of children were considered to give reliable results close to what is normal for adults. It would be interesting to further investigate the potential of the Rarebit fovea test for evaluation of foveal function in children.     

Retinal symmetry of multifocal visual evoked potential in both eyes of normal subjects

Purpose: To analyze the retinal symmetry of muhifocal visual evoked potential(mfVEP) in both eyes of normal subjects.Methods: The monocular mfVEP in both eyes of 36 normal subjects (72 eyes) weretested with VERIS Science 4.0. The stimulus was the pattern reversal dart array con-sisted of 60 sectors each including 16 black-white reverse patterns. The visual stimu-lation was controlled by a binary pseudo-random m-sequence and subtended 25 de-grees of retinal region.Results: The nffVEP patterns between left and right eyes of each subject were similar,and P1 latency and amplitude in correspondent visual field quadrants between left and right eyes had no significant difference (P>0.05). The latency of superotemporal visual field quadrant in right eyes was shorter than that of superonasal visual field quadrant in left eyes, and the amplitude of superonasal visual field quadrant in right eyes was longer than that of superotemporal visual field quadrant in left eyes (P<0.05). The P1latency and amplitude among four visual field quadrants of each eye had significant difference (P<0.05). The P1 latency between the superonasal visual field quadrant and inferotemporal visual field quadrant or between the superonasal visual field quadrant and inferonasal quadrant visual field had significant differences in right or left eyes(P<0.05).Conclusion: The mfVEP of normal subjects exists retinal symmetry.     

多焦视诱发电位的双眼对称性分析

目的 观察正常人多焦视诱发电位(mfVEP)的双眼对称性。 方法 应用VERIS Science 4.0视觉诱发反应图像系统对36名正常人的72只眼进行mfVEP测试，刺激图形为带图形的飞镖盘，对应的视角为25°。图形中有60个小块，每个小块包括4×4个黑白相间的格子，由二元伪随机m-序列控制其黑白翻转形成视觉刺激。 结果 左右眼各对应象限的P1波潜伏期及振幅配对 t 检验显示差异无统计学意义。双眼同侧视野的潜伏期与振幅的数据差异大于相应视野象限的数据差异。右眼或左眼4个象限组间比较显示双眼各自鼻上与颞下、鼻下象限P1波潜伏期之间差异有统计学意义，振幅方面仅左眼颞上与颞下象限之间差异有统计学意义。 结论 正常人双眼mfVEP以视网膜对称性优于视皮层的对称性。 (中华眼底病杂志, 2006, 22: 42-44)