左旋多巴改善屈光参差性弱视视功能的远期效果

目的：观察“思利巴”的有效成分左旋多巴改善屈光参差性弱视单字视力、拥挤视力、对比敏感度、立体视的远期效果。方法：61例5．5－15岁难治性屈光参差性弱视患者，被随机分成实验组和对照组，两组均用传统治疗，实验组加服思利巴3个月，观察两组实验前，实验第1个月、第2个月、第3个月、第6个月、第9个月末的单字视力、拥挤视力、对比敏感度变化及实验前和实验第9个月的立体视变化。结果：（1）服药组弱视眼：（1）单字视力：第1个月、第2个月逐渐提高且变化有显著性。（2）拥挤视力：第1个月提高有显著性。（3）对比敏感度：服药后1个月中低空间频率改善有显著性，高空间频率无变化。以上结果均保持到实验结果。（2）立体视变化无显著性。（3）服药组优势眼及对照组比较，各项指标无变化。结论：（1）服药2个月后，可改善难治性屈光参差性弱视眼的单字视力，服药1个月可改善拥挤视力。（2）思利巴可改善中低空间频率的对比敏感度。（3）服用思利巴3个月对立体视及优势眼无影响。     

正常与屈光不正性弱视儿童视知觉检查的比较

目的了解对比敏感度、噪声、拥挤现象三种视知觉检查在正常儿童与屈光不正性弱视儿童间的差异。设计前瞻性病例系列。研究对象正常儿童50例,屈光不正性弱视儿童50例。方法应用国家医疗保健器具工程研究中心研发的视知觉检查测评系统中的噪声视力表、拥挤视力表、对比敏感度视力表检查正常儿童及屈光不正性弱视儿童各50例。根据检测结果对弱视组和正常组进行比较分析,并对弱视组中不同弱视程度和不同屈光度之间进行比较。主要指标对比敏感度、噪声、拥挤现象的正常和异常人数及构成比。结果弱视儿童及正常儿童对比敏感度异常者分别为60眼（60．00％）和15眼（15．00％）,噪声异常者分别为62眼（62．00％）和30眼（30．00％）,拥挤异常者分别为56眼（56．00％）和0眼（0％）（P均=0．000）。轻度、中度、重度弱视者对比敏感度异常者分别为32眼（51．61％）、20眼（66．67％）、8眼（100％）（P=0．005）;拥挤异常者分别为30眼（48．39％）、18眼（60．00％）、8眼（100％）（P=0．010）。噪声异常者分别为39眼（69．90％）、18眼（60．00％）、5眼（62．50％）（P=0．868）。弱视患者轻度、中度、重度屈光不正者,对比敏感度异常者分别为33眼（70．21％）、9眼（34．12％）、17眼（62．96％）（P=0．011）;噪声异常者分别为30眼（63．83％）、15眼（57．69％）、17眼（62．96％）（P=0．868）;拥挤异常者分别为30眼（63．83％）、11眼（42．31％）、17眼（62．96％）（P=0．172）。结论对比敏感度、噪声、拥挤现象三种视知觉检查可以用来评估弱视患者视知觉损害状态。（眼科,2010,19：113-116）     

视觉敏感期后弱视研究的新进展

弱视是指眼部无明显器质性病变,单眼或双眼的最佳矫正视力低于相应年龄的标准。然而,视觉敏感期后的弱视是患病率较高的眼部疾病,全球有接近3%的高发病率,但以往对于这类患者却是放弃治疗的。目前,视觉敏感期后弱视机制研究的热点之一就是对视觉系统可塑性的重新认识。本文就这一热点领域,针对视觉关键期后视觉系统可塑性的临床和基础研究、视觉敏感期后弱视治疗的进展等作一综述。     

斜视性弱视与屈光参差性弱视对比敏感度函数的研究

目的研究斜视性弱视及屈光参差性弱视患者弱视眼的对比敏感度函数。方法用稳态ＶＥＰ的方法对３２例斜视性弱视、１９例屈光参差性弱视及正常儿童的对比敏感度进行测定。结果两种弱视患者弱视眼的ＣＳＦ均较正常儿童的ＣＳＦ低平，表现为中、高空间频率区ＣＳＦ明显受损，而两种弱视间的ＣＳＦ未见显著性差异。结论两种弱视可能均为Ｘ通道受损所致。     

弱视视功能损害特点

目的：弱视是一种视觉异常,表现为没有明显眼部器质性病变的空间视力低下。弱视存在多种视功能障碍,并且不同类型弱视的视功能损害还表现出不同程度的差异。本文从视力、光栅视力、游标视力、对比敏感度、双眼视觉、视知觉以及色觉等方面对弱视的视功能损害特点进行探讨,以期有助于弱视的评估和治疗。     

弱视视觉抑制的心理物理学研究进展

近年来动物实验、心理物理学研究发现,弱视视皮层结构上为双眼,视觉抑制使其功能上表现为单眼,并认为视觉抑制是引起弱视视觉功能损害的重要机制.本文主要对心理物理学领域视觉抑制在弱视视觉系统的重要作用和视觉抑制的测量、调控,以及针对视觉抑制的双眼平衡治疗模式的研究做一总结.     

屈光参差性弱视儿童双眼视觉状态

目的：分析屈光参差性弱视儿童的屈光状态、矫正视力情况及其与双眼视觉功能的关系。方法：横断面研究。收集2015年11月至2016年9月就诊于北京9家医院（分布于8个区县）的屈光参差性弱视儿童患者106例（106眼）,年龄（6.2±5.4）岁。根据屈光参差危险因素将所有患者分为远视性屈光参差组（67例）、近视性屈光参差组（5例）、散光性屈光参差组（12例）、远视合并散光性屈光参差组（20例）及近视合并散光性屈光参差组（2例）。对所有患者行裸眼视力（UCVA）、矫正视力（BCVA）、屈光状态、远近立体视等检查。采用Pearson相关性分析双眼屈光参差的差值程度与高度屈光不正眼UCVA、BCVA及双眼视觉间的相关性,并分析双眼矫正视力差值程度与双眼视觉的相关性。采用单因素方差分析比较5组高度屈光不正眼BCVA及远近立体视情况。结果：屈光参差的差值程度与高度屈光不正眼UCVA和BCVA、远立体视、近立体视（即随机点立体视,包括立体视锐度、交叉立体视、非交叉立体视）均呈负相关（均P<0.05）;双眼矫正视力差值与远立体视、近立体视均呈负相关（均P<0.05）。5组间在高度屈光不正眼BCVA、远立体视、近立体视方面总体差异均有统计学意义（F=6.221、5.271、3.622、3.647、3.464,P<0.05）,进一步两两比较显示高度屈光不正眼BCVA在近视性屈光参差组最好,然后依次为远视性屈光参差组、散光性屈光参差组、近视合并散光性屈光参差组以及远视合并散光性屈光参差组,组间差异均有统计学意义（均P<0.05）;远立体视在远视性屈光参差组最好,然后依次为近视性屈光参差组、散光性屈光参差组,组间差异均有统计学意义（均P<0.05）,但远视合并散光性屈光参差组与近视合并散光性屈光参差组的远立体视差异无统计学意义;近立体视在近视性屈光参差组最好,然后依次为远视性屈光参差组、散光性屈光参差组、远视合并散光性屈光参差组以及近视合并散光性屈光参差组,组间差异均有统计学意义（均P<0.05）。结论：屈光参差性弱视儿童的屈光参差程度与视力、立体视功能相关,且立体视功能和双眼矫正视力差值也有相关性。不同类型屈光参差儿童立体视损害有所差异。     

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。     

视觉可塑性相关因子和环境对弱视治疗影响的研究进展

弱视是引起儿童单眼视力低下最常见的原因,世界人口患病率为1%～5%,我国儿童弱视患病率约为2%～4%,且有逐年上升的趋势。弱视主要发生在儿童视觉发育的敏感期内,因为该时期视觉发育具有可塑性,而这种可塑性易受到多种因素的影响而导致视觉系统不同的发育轨迹。随着年龄的增长,视觉可塑性即消失,此时弱视的治疗效果甚微,故当视觉系统仍保持可塑性时是弱视治疗的黄金时期。近些年有大量针对视觉可塑性的研究,希望充分利用这一特性来逆转弱视的发生发展。目前已知视觉可塑性受到神经因子、生活环境等多方面的影响。本文将从兴奋性神经因子、脑源性生长因子、抑制性神经因子、环境影响方面入手,对目前针对视觉可塑性的研究进展做一综述。     

多焦视觉电生理在弱视中的研究进展

弱视的视觉电生理检查是近年来弱视研究的新兴技术,主要包括视网膜电图、视觉诱发电位。多焦视觉电生理的临床应用对研究弱视的视皮质、视觉传导和视网膜的功能更具有重要的临床意义,它的发展及应用为弱视的早期诊断和治疗提供了新的有力依据。我们就此进行较全面的综述。     

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     

左旋多巴对屈光参差性弱视患儿视力的影响

目的：观察息宁（左旋多巴／卡比多巴）对难治性屈光参差性弱视患儿视力的影响,探讨左旋多巴用药时间和治疗机理。方法：给３２例（５￣１５岁）经传统疗法治疗至少６个月无效的屈光参差性弱视患儿口服息宁１ｍｇ／０．２５ｍｇ／ｋｇ,一日三次,连续６０天。观察服药前及服药后第３、６、９、３０、６０天单字Ｅ视力的变化。结果：弱视眼和优势眼的单字视力服药后第３天提高,差异有极显著性（Ｐ〈０．０１）,继续服药无进一步改     

Perceptual learning improves contrast sensitivity and visual acuity in adults with anisometropic amblyopia

To evaluate the effects of perceptual learning on contrast-sensitivity function and visual acuity in adult observers with amblyopia, 23 anisometropic amblyopes with a mean age of 19.3 years were recruited and divided into three groups. Subjects in Group I were trained in grating detection in the amblyopic eye near pre-training cut-off spatial frequency. Group II received a training regimen of repeated contrast-sensitivity function measurements in the amblyopic eye. Group III received no training. We found that training substantially improved visual acuity and contrast-sensitivity functions in the amblyopic eyes of all the observers in Groups I and II, although no significant performance improvement was observed in Group III. For observers in Group I, performance improvements in the amblyopic eyes were broadly tuned in spatial frequency and generalized to the fellow eyes. The latter result was not found in Group II. In a few cases tested, improvements in visual acuity following training showed about 90% retention for at least 1 year. We concluded that the visual system of adult amblyopes might still retain substantial plasticity. Perceptual learning shows potential as a clinical tool for treating child and adult amblyopia.     

刺激条件对扫描图像翻转诱发电位视力的影响

目的研究时间频率和空间频率对扫描图像翻转诱发电位视力准确度的影响。方法比较10例20眼正常志愿者SPVER视力和对数视力表视力。在SPVER视力的测定中用7个不同空间频率的光栅条纹连续扫描。所得的数据经离散傅立叶分析后，获得振幅-空间频率曲线，并通过外推法估计其视力。诱发电位测定的时间频率分别为8、12、16、20、24Hz，根据测试距离来调整空间频率。结果与视力表视力比较各时间频率测定的SPVER视力有良好的相关r=0．87～0．5，各空间频率间测定的视力有良好的相关性r=0．72～0．96。三种不同空间频率测试的SPVER视力和视力表视力比较在低视力段无差异在高视力段所设空间频率越高结果越接近视力表视力。结论SPVEP视力与视力表视力有良好的相关性。但为使测定的结果更准确可根据条件选取相应的时间和空间频率。     

Discrimination of position and contrast in amblyopic and peripheral vision

Many computational models of normal vernier acuity make predictions based on the just-noticeable contrast difference. Recently, Hu, Klein and Carney [(1993) Vision Research, 33, 1241–1258] compared vernier acuity and contrast discrimination (jnd) in normal foveal viewing using cosine gratings. In the jnd stimulus the test grating was added in-phase to the (sinusoidal) pedestal, whereas in the vernier stimulus the same test grating was added with an approx. 90 deg phase shift to the pedestal. In the present experiments, we measured thresholds for discriminating changes in relative position and changes in relative contrast for abutting, horizontal cosine gratings in a group of amblyopes using the Hu et al., test-pedestal approach. The approach here is to ask whether the reduced vernier acuity of amblyopes can be understood on the basis of reduced contrast sensitivity or contrast discrimination. Our results show that (i) abutting cosine vernier acuity is strongly dependent on stimulus contrast. (ii) In both anisometropic and strabismic amblyopes, abutting cosine vernier discrimination thresholds are elevated at all contrast levels, even after accounting for reduced target visibility, or contrast discrimination. (iii) For both strabismic and anisometropic amblyopes, the vernier Weber fraction is markedly degraded, while the contrast Weber fraction is normal or nearly so. (iv) In anisometropic amblyopes the elevated vernier thresholds are consistent with the observers' reduced cutoff spatial frequency, i.e. the loss can be accounted for on the basis of a shift in spatial scale. (v) In strabismic amblyopes and in the normal periphery, there appears to be an extra loss, which can not be accounted for by either reduced contrast sensitivity and contrast discrimination or by a shift in spatial scale. (vi) This extra loss cannot be quantitatively mimicked by “undersampling” the stimulus. (vii) Surprisingly, in some strabismics, and in the periphery, at relatively high spatial frequencies, vernier thresholds appear to lose their contrast dependence, suggesting the possibility that there may be qualitative differences between the normal fovea and these degraded visual systems. (viii) This contrast saturation can be mimicked by “undersampling” the target, or by introducing strips of mean luminance between the two vernier gratings, thus mimicking a “scotoma”. Taken together with the preceding paper, our results suggest that the extra loss in position acuity of strabismic amblyopes and the normal periphery may be a consequence of noise at a second stage of processing, which selectively degrades position but not contrast discrimination.     

屈光参差性弱视治疗的空间频率评价

目的 观察弱视治疗的空间频率变化特点.方法 对屈光参差性弱视52只眼,随机分为治疗组(26只眼)和未治疗组(26只眼).治疗组采用SZ-C综合治疗仪治疗,观察治疗前后视力变化情况、不同空间频率图形翻转VEP的P100波振幅和峰潜时改变以及眩光对比敏感度不同空间频率改变.结果 治疗后视力变化差异具有统计学意义(p＜0.01),两组间P100波振幅和峰潜时差异具有统计学意义(p＜0.01),但治疗前后高空间频率P100波未见统计学差异.眩光对比敏感主要表现为高空间频率异常.结论 视力不是评价弱视疗效的惟一标准,应重视进一步的视觉功能训练.     

Factors affecting the stability of visual function following cessation of occlusion therapy for amblyopia

Aim To identify factors that predict which children with amblyopia are at greatest risk of regression of visual acuity (VA) following the cessation of occlusion therapy. Method A retrospective analysis was performed of 182 children (mean age at cessation of treatment; 5.9±1.6 years) who had undergone occlusion therapy for unilateral amblyopia, and had been followed up at least once within 15 months of cessation. Statistical analysis was used to identify whether change in VA following treatment cessation had any association with various factors, including the child’s age, type of amblyopia, degree of anisometropia, initial severity of amblyopia, binocular vision status, length and dose of occlusion therapy, and VA response to treatment. Results At 1 year, follow-up from treatment cessation, children with “mixed” amblyopia (both anisometropia and strabismus) demonstrated significantly (p=0.03) greater deterioration in VA (0.11±0.11 log units) than children with only anisometropia (0.02±0.08 log units) or only strabismus (0.05±0.10 log units). However, none of the other factors investigated were found to be significant predictors. Conclusion This study supports previous research that it is possible to identify those children most at risk of deterioration in VA following cessation of occlusion therapy. The presence of mixed amblyopia was the only risk factor identified in this study. Management of amblyopia should take this into account, with a more intensive follow-up recommended for those with both anisometropia and strabismus (mixed) amblyopia.     

Prevalence of amblyopia among defaulters of preschool vision screening

The prevalence of amblyopia among screening defaulters is an important determinant of the efficacy of amblyopia detection by preschool vision screening. A retrospective cohort study was therefore performed to assess an orthoptist-based preschool vision screening programme. The preschool vision screening status of children in the cohort was determined by reviewing their Community Child Health records. The prevalence of amblyopia among screening defaulters was determined by reviewing each child's school entry vision test (performed at 5.5 years of age), with retesting if a Snellen line acuity of 6/6 in each eye had not been documented. For comparison, the prevalence of amblyopia among screening attenders was also determined. The preschool vision screening status was known for 86.0% (772/898) of the cohort. The attendance rate at preschool vision screening was 79.2%. The prevalence of amblyopia among screening defaulters was 1.3% (95% CI 0.2% to 4.5%). The prevalence of amblyopia among screening attenders was 2.5% (95% CI 1.4% to 4.1%). There was no significant difference in the prevalence of amblyopia between screening defaulters and screening attenders (P=0.53). The efficacy of amblyopia detection by preschool vision screening is therefore highly dependent on its attendance rate. Preschool vision screening programmes with a low attendance rate will fail to detect a significant proportion of children with amblyopia.     

Combining vernier acuity and visual backward masking as a sensitive test for visual temporal deficits in aging research

Performance in many everyday situations slows down when age increases. The causes of slowing down may be found on any stage of information processing. Here, we show that the combination of a vernier acuity task and the shine-through backward masking paradigm is a good paradigm to determine temporal processing deficits. The paradigm is relatively robust to optical blur and unlikely affected by motor dysfunctions. Strong masking deficits are found from an age of about 50 years on.