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.     

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.     

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。     

斜视性弱视多焦VEP与多焦ERG的对比研究

目的对比研究斜视性弱视患者多焦视觉诱发电位(multifoeal VEP)及多焦视网膜电图(mERG)的特征性变化，探讨弱视发病的可能机制。方法采用VERIS Science^TM4．2多焦电生理系统记录并比较正常组30例、斜视性弱视患者20例各眼mVEP及mERG。结果弱视眼不同视网膜区域mVEP、mERG的特征峰反应振幅密度都较对侧眼和正常眼明显降低，mVEP的特征峰潜时延长。弱视眼mVEP、mERG波形异常程度随离心度增加而减小，mVEP波形异常程度大于mERG，且与弱视眼的视力异常程度有相关性。结论斜视性弱视患者的mVEP和mERG具有明显的特征性改变，表明弱视患者的视网膜、视皮层都存在明显损害。     

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。     

儿童屈光参差性和斜视性弱视多导图形视觉诱发电位的研究

目的通过用多导图形视觉诱发电位（Ｐ－ＶＥＰ）进一步研究儿童弱视的发病机制及两种弱视之间的相互关系。方法采用１６导视觉诱发电位仪，分别检查了２５例屈光参差性弱视和３３例内斜视性弱视，将检查的Ｐ－ＶＥＰ三个主要参数分别与正常对照组和弱视眼对侧眼的相应参数进行了比较。结果两种类型弱视的三个主要参数的平均结果都发生了明显的改变，内斜视性弱视的对侧眼与正常对照组相比Ｎ１、Ｐ１波的潜伏期也明显延长，振幅下降，说明内斜视对侧眼并非正常；结果还提示屈光参差性弱视其振幅比值较其对侧眼小于０．８、潜伏期大于５ｍｓ，可作为诊断的参考依据。结论临床上根据Ｐ－ＶＥＰ的检查结果来判断弱视是可靠的     

弱视儿童非弱视眼的视觉诱发电位分析

双８４例儿童正常视力眼的视觉诱发电位（ｖｉｓｕａｌ ｅｖｏｋｅｄ ｐｏｔｅｎｔｉａｌ，ＶＥＰ）进行了分析，其中正常儿童２０人，屈光参差性弱视儿童２８人，治愈的屈光参差性弱视儿童８人，单卵双生子８对，双卵双生子６对。结果表明：弱视的对侧眼及已治愈的弱视眼，尽管视力完全正常，但ＶＥＰ仍表现异常，以Ｐ１００波潜伏期延长明显；双生子中遗传物质相同的单卵双生子，其视力正常眼与弱视眼间的ＶＥＰ差异无显著性意义     

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。     

知觉学习改善屈光参差性弱视视功能的临床观察

目的探讨知觉学习训练在改善青少年及成人屈光参差性弱视患者视功能方面的效果。方法前瞻性自身对照研究。共纳入18例青少年和成年单眼屈光参差性弱视患者,弱视眼在截止空间频率下进行对比度检测任务的训练,对侧相对健眼作为对照。患者随访3～6个月。分别观察患者训练前后的最佳矫正视力和对比度阈值改变,立体视改变以及试验组训练前后视觉诱发电位改变。数据进行t检验、相关性分析。结果弱视眼与相对健眼相比,其在训练前后的视力改变,截止空间频率下的对比度阈值改变,以及所有空间频率下的对比度阈值改变差异均有统计学意义（t=2.731,P<0.05;t=5.108,P<0.01;t=3.700,P<0.01）,弱视眼及对侧眼在训练前后潜伏期变化,振幅变化差异均无统计学意义,并且18例中有8例立体视得到改善。12例患者随访3个月,弱视眼视力平均保持了99.3%,对侧眼视力改善平均保持了50%。结论知觉学习能改善青少年及成年屈光参差性弱视患者的视功能,可用于治疗大龄弱视。     

斜视性弱视儿童不同注视性质多焦视觉诱发电位的研究

目的对比研究斜视性弱视不同注视性质患者多焦视觉诱发电位特征性变化,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,提取FOK(一阶反应)。共记录和分析了不同注视性质斜视性弱视儿童52眼(中心凹型26眼;黄斑型21眼;黄斑周围型5眼),并与正常注视性质对照组儿童(60眼)作比较。结果斜视性弱视眼:中心凹注视眼图形中央区振幅下降陡峭,潜伏期最长。随离心度加大,周边区振幅下降平缓;黄斑注视眼中央区振幅下降平缓,潜伏期减小。随离心度加大,周边区振幅逐步下降;黄斑周围注视眼图形杂乱,中心至周边一侧可见多个小的异常波峰隆起,呈不对称分布。黄斑型注视组与黄斑周围型注视组在不同离心度mfVEP反应无统计学差异。结论虽然旁中心注视眼mfVEP不能反映视网膜中心区真实机能,但是异常网膜对应区域受到的抑制还是重于周边区域。     

屈光参差性弱视同步记录多焦视觉诱发电位和多焦视网膜电图的对比研究

目的探讨弱视发病的可能机制。方法采用VERIS Science^TM4．2多焦电生理系统对24例屈光参差性弱视患者双眼分别进行多焦图形视觉诱发电位(VEP)、视网膜电图(ERG)同步记录和多焦闪光VEP、ERG同步记录,并与30例正常对照的结果进行比较。结果在不同视网膜区域弱视眼多焦图形VEP、ERG反应和多焦闪光VEP、ERG二阶反应振幅均降低,VEP特征峰潜时延长,ERG潜时无改变。弱视眼多焦闪光一阶反应VEP、ERG的反应振幅密度均降低,潜时无明显改变。多焦图形VEP波形异常程度中心区大于周边区,且与弱视眼的视力异常程度有相关性。弱视眼多焦图形和闪光二阶反应的视网膜．皮层传导时间(RCT)显著延长,闪光一阶反应RCT三组无明显差异。结论弱视眼的mVEP和mERG具有明显的特征性改变,表明弱视眼的视网膜、视觉传导通路和视皮层都存在明显损害,且中心区损害重于周边区,中枢损害重于视网膜。(中华眼科杂志,2005,41：41-46)     

Automated perimetry in amblyopia: a generalized depression

PURPOSE: To quantitate the visual field abnormalities associated with amblyopia. METHODS: In a prospective study, 37 amblyopic patients (11 anisometropic, 13 strabismic, 9 combination, 4 deprivation) performed automated perimetry in each eye using the Humphrey 30-2 program. Primary outcome measures were foveal threshold, mean deviation, and average threshold. RESULTS: When the probability plots were examined, 21 visual fields in amblyopic eyes were normal, 8 had central scotomas, and 7 had diffuse depressions. No focal defects other than mild central scotomas were seen. However, the foveal threshold of amblyopic eyes was decreased by an average of 7.2 +/- 8.0 dB (P < .0001) compared with fellow eyes; intereye differences in mean deviation (3.2 +/- 5.4 dB; P < .001) and average threshold (2.9 +/- 5.3 dB; P < .005) were also seen. This decrease in sensitivity for the amblyopic eye occurred for all types of amblyopia. The depression in threshold was greatest at the fovea but was detectable and significant at all eccentricities of the 30-degree field. The average threshold in the amblyopic eye was highly correlated with visual acuity (r = .839; P < .001). CONCLUSIONS: Although automated visual fields in amblyopic eyes typically appear normal, all four types of amblyopia are associated with a generalized depression of light sensitivity, which is proportionately greatest at the fovea and highly correlated with visual acuity loss. In general, amblyopia is not associated with any area of focal loss of threshold light sensitivity. If a focal defect is present in the visual field of the amblyopic eye, organic causes of visual loss should be suspected. The Humphrey visual field analyzer STATPAC program (Allergan-Humphrey, Inc, San Leandro, California) may artifactually transform small and generalized full-field depressions in a manner that makes them appear to be isolated central defects.     

Long-term changes in visual acuity and refractive error in amblyopes.

PURPOSE: To report long-term changes in visual acuity and refractive error for strabismic, anisometropic, and isoametropic amblyopes. METHODS: Records of patients with strabismic amblyopia, anisometropic amblyopia, and isoametropic amblyopia who were treated from 1983 to 1993 were reviewed. Excluded were patients having ocular or neurological diseases, developmental delay, and follow-up <4 years after treatment cessation. Data included best-correctable visual acuity and spherical equivalent refractive error of the amblyopic and the nonamblyopic eye at pretreatment, posttreatment, and long-term follow-up. RESULTS: Records for 61 patients met the inclusion criteria. For strabismic amblyopia (n = 22), mean visual acuity in amblyopic and nonamblyopic eyes improved 0.36 and 0.05 logarithm of the minimum angle of resolution (logMAR) units after a mean treatment time of 1 year. At long-term follow-up (mean = 9.3 years after treatment), visual acuity in the amblyopic eye regressed 0.09 logMAR and visual acuity in the nonamblyopic eye improved 0.10 logMAR units. For anisometropic amblyopia (n = 26), mean visual acuity in amblyopic and nonamblyopic eyes improved 0.30 and 0.02 logMAR units, respectively, after a mean treatment period of 1.1 year. At the long-term follow-up visit (mean = 7.1 years after treatment), visual acuity in the amblyopic eye regressed 0.09 logMAR unit and in the nonamblyopic eye improved 0.03 logMAR unit. Repeated-measures analysis of variance showed no significant effect of type of amblyopia on visual acuity of the amblyopic eye and a significant effect of visit due to treatment but not regression. The changes in visual acuity in the nonamblyopic eye from the pretreatment to the follow-up visit were significant and interacted with type, the changes being larger in strabismic amblyopia. For strabismic amblyopia, the mean refractive error in amblyopic and nonamblyopic eyes changed from +2.15 D and +1.85 D, respectively, initially to +0.45 D and +0.58 D, respectively, at the follow-up visit. For anisometropic amblyopia, the mean refractive error in amblyopic and nonamblyopic eyes changed from +1.04 D and +0.12 D, respectively, initially to +0.23 D and -0.94 D, respectively, at the follow-up visit. The effect of visit on amblyopic and nonamblyopic refractive errors was significant. For isoametropic amblyopia (n = 13), visual acuity in both right and left eyes initially was 0.39 logMAR unit and improved to 0.14 logMAR unit in each eye after a mean follow-up of 8.9 years. Refractive error in the right and the left eyes changed from -1.22 D and -1.14 D, respectively, to -2.68 D and -2.56 D, respectively, at follow-up. These differences were all significant. CONCLUSIONS: After treatment and with long-term follow up, visual acuity regresses but not significantly in the amblyopic eye in strabismic amblyopia and anisometropic amblyopia. At the same time, visual acuity in the nonamblyopic eye improves slightly. Visual acuity also improves significantly over time in isoametropic amblyopia. The refractive error of both amblyopic and nonamblyopic eyes tends to show a myopic shift regardless of the type of amblyopia.     

Visual evoked potential importance in the complex mechanism of amblyopia

To compare the visual evoked potential (VEP) responses of amblyopic eyes with VEP responses of sound eyes in amblyopic children. A study of 65 amblyopic children with pattern-reversal VEPs elicited by checkerboard stimuli with large, medium and small checks. The children were classified into three groups: Group A, 22 children with anisometropic amblyopia; Group B, 16 children with exotropic strabismic amblyopia; and Group C, 27 children with esotropic strabismic amblyopia. Visual acuity (VA) was significantly worse in the amblyopic eye as compared to the sound eye. However, no statistically significant difference was found between the amblyopic and sound eye of amblyopic children in the three groups for VEP P1 amplitude and latencies for any check sizes. VEP is a very important tool in understanding the complex amblyopic mechanism. Although the sound eye has superior VA, the absence of differences in VEP P1 amplitudes and latencies demonstrate the functional abnormality of the eye considered ‘good’. More studies are necessary to explain why the sound eye in amblyopic children cannot be considered completely normal. Special attention should therefore be paid to amblyopic treatment, as patching can have a negative effect on the sound eye.     

Is the motion system relatively spared in amblyopia? Evidence from cortical evoked responses

Visual evoked potentials (VEPs) produced by pattern reversal were compared with those elicited by onset of motion in 37 amblyopic children (20 with anisometropic amblyopia, seven with strabismic amblyopia and 10 with both anisometropia and strabismus). The amplitudes and peak latencies of the main P₁ peak in the pattern-reversal VEP and of the motion-specific N₂ peak in the motion-onset VEP through the amblyopic eye were compared with those through the normal fellow eye. Regardless of the type of amblyopia, the amplitude of the pattern-reversal VEP for full-field stimulation was significantly smaller and its latency significantly longer through the amblyopic eye (P < 0.001). In contrast, neither the amplitudes nor the latencies of the N₂ motion-onset VEPs differed significantly between amblyopic and non-amblyopic eyes. For pattern-reversal VEPs through the amblyopic eyes, the extent to which amplitude was reduced and latency prolonged correlated well with the reduction of visual acuity, whereas the amplitudes and latencies of motion-onset VEPs did not vary with visual acuity. Even for stimuli restricted to the central visual field (5 or 2 deg diameter) or to the peripheral field (excluding the central 5 deg), motion-onset responses were indistinguishable through the two eyes, while pattern-reversal responses always differed significantly in amplitude. These results suggest that the source of motion-onset VEPs (probably an extrastriate motion-sensitive area) is less affected in amblyopia than that of pattern-reversal VEPs (probably the striate cortex). The motion pathway, presumably deriving mainly from the magnocellular layers of the lateral geniculate nucleus, may be relatively spared in amblyopia.     

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)     

The contrast sensitivity function and childhood amblyopia

We measured contrast sensitivity function and visual acuity in both eyes of strabismic and anisometropic amblyopic patients. There was a linear relationship between contrast sensitivity function and visual acuity in the amblyopic eye. As visual acuity decreased, the contrast sensitivity function decreased along the contrast sensitivity axis, and peak sensitivity shifted to lower spatial frequencies. After patching therapy, when visual acuity reached 20/20 in each eye, suggesting that the amblyopia was cured, there continued to be statistically significant difference in the contrast sensitivity functions between the eyes. The contrast sensitivity function from the previously amblyopic eye was depressed compared to the nonamblyopic eye. A comparison between patients with strabismic and anisometropic amblyopia showed that, when matched for visual acuity, the contrast sensitivity functions were similar for both the nonamblyopic and amblyopic eyes. However, a large difference was found between the amblyopic and nonamblyopic eyes of each group.     

Defective processing of motion-defined form in the fellow eye of patients with unilateral amblyopia.

The following three measurements were made on a group of 20 pediatric and 5 adult patients with unilateral amblyopia: (1) speed threshold for recognizing motion-defined dotted letters; (2) recognition acuity for isolated solid letters of 4% contrast; and (3) Snellen line acuity for high-contrast letters. Normal limits were established with a group of 30 pediatric and 10 adult control subjects. The main finding was that, in amblyopic children, a high percentage (83%, 15 of 18) of fellow eyes showed a degraded ability to recognize motion-defined letters, even though Snellen acuity and 4% letter acuity were normal for age. The fellow eyes of all nine patients with strabismic amblyopia showed this pattern of loss, as did four of six fellow eyes of patients with anisometropic amblyopia and two of three fellow eyes of patients with anisometropic plus strabismic amblyopia. Only two clinically unaffected eyes were normal for motion-defined letters. These eyes belonged to patients with anisometropic amblyopia. Eighteen of the 19 previously amblyopic eyes tested were abnormal for motion-defined letters even though Snellen acuity was within normal limits for 6 of these eyes. In adults, only one of five fellow eyes failed the motion-defined letter test. It was concluded that the degradation of form perception associated with amblyopia can be different for luminance-defined and motion-defined form and that defective processing of motion-defined form is common in the fellow eyes of children with unilateral amblyopia.     

Effects of luminance on the visual acuity of strabismic and anisometropic amblyopes and optically blurred normals

Evidence is accumulating to suggest fundamental differences between strabismic and anisometropic amblyopia. We explored differences in these amblyopes by assessing the effects of luminance on optotype acuity, using targets that ranged from photopic to low mesopic levels. Our results show that reducing luminance has less of a detrimental effect on the acuity of strabismic than anisometropic amblyopic eyes. Furthermore, the effect of decreasing luminance on the acuity of optically blurred normal eyes mimicked the effect we found for anisometropic amblyopic eyes. These results are consistent with the hypothesis that the fundamental deficit in anisometropic amblyopia is impaired resolution while in strabismic amblyopia the fundamental deficit is impaired spatial directionalization.