Visual acuity norms in young children

There are no universally accepted standards for visual acuity tests or norms in young (3-6-year-old) children, although acuity measurement is important in both clinical and screening settings. This review outlines the requirements for such standards. Although more research is needed, available data suggest that a standard test should meet the following requirements. It should utilize a letter optotype (tumbling E, Landolt C, or HOTV variant of the STYCAR), and single optotype with contour interaction bar surround. It should permit nonverbal pointing responses in younger children and verbal responses in older children. If an orientation-specifying method is followed, as with the E or Landolt C, the test should use a three-alternative choice--up, down, and sideways with a nondifferentiated left-right--rather than the traditional four alternative choice. A C-like O pseudo-optotype should be considered in a paired-comparison test format when the Landolt C is utilized, with a similar format for the tumbling E if a suitable pseudo-optotype can be derived. The optical grating test, which is widely used in infant testing, may underestimate acuity deficits and so is not a test of choice for determination of Snellen-equivalent acuity. A letter-based variant of the grating test may hold promise. Reduction in testing distance from 6 to 3 or 4 meters is recommended.     

3～6岁学龄前儿童的视力发育曲线比较性研究

目的用不同的方法检查正常3～6岁学龄前儿童的视力,比较研究学龄前儿童正常视力发育的曲线表现,并探讨不同年龄段儿童可行的视力检查方法。方法对幼儿园身体健康状况良好、无眼部器质性病变、屈光度在正常生理值范围的3～6岁的学龄前儿童检查条栅视力、E字视力、图形视力。结果(1)对不同的视力检查方法,幼儿的视力发育趋势表现有所不同,视力发育成熟的年龄亦有差异。其中,条栅视力发育较快,在3岁左右达到5.0;图形视力和E字视力发育接近,6岁以后达到5.0。(2)就3～6岁之间幼儿的视力发育呈阶段性,大致可分为2岁10个月～3岁3个月、3岁4个月～4岁3个月、4岁4个月～4岁9个月和5岁4个月～6岁3个月四个阶段,P<0.01,差异有显著性;其中,2岁10个月～3岁3个月和4岁4个月～4岁9个月两阶段视力发育更敏感,持续时间相对较短,为半年;继这两个阶段之后分别是两个视力发育相对缓慢期,为3岁4个月～4岁3个月和5岁4个月～6岁3个月两个年龄段,持续时间较长,约为一年。结论视力发育过程不仅与视神经传导功能的发育有关,还与幼儿的心理发育及认知能力有关;针对3～6岁的学龄前儿童,其视力检查以E字视力最敏感;其视力发育曲线可为视力普查时判断幼儿视力是否正常提供参考值。     

噪声视力表在儿童视力检查中的可重复性分析

目的探讨噪声视力表对儿童视力检查的可重复性及其相关影响因素。方法在门诊首诊患儿中,随机选择无理解障碍及除屈光不正外无其他器质性眼病儿童200例,使用噪声视力表进行噪声视力重复检查。采用配对t检验进行统计学分析。结果两次视力测量之间差异的均数为O.03行,（P=0.515）;两次视力测量结果按性别分组无明显差异（P=1.0,P=0.262）;按年龄分组亦无明显差异（P=0.159,P=0.786）;按屈光不正分组,其中近视组两次视力测量结果有明显差异（P=0.010）。近视儿童视力检查一致性较差,而正视及远视儿童的视力检查一致性较好（P=0.133,P=0.083）。结论结果提示噪声视力表适合儿童视力检查,建议推广使用。     

The determination of the central static visual acuity,presentation of a modified Landolt C chart

The circumstances which can influence the determination of the static central visual acuity are enumerated. The TNO Landolt C chart can be improved. A modified Landolt C letter chart is introduced on which the optotype is presented in 8 different positions, in vertical rows of ten per visual step above visual acuity 0.3. Address for corresspondence: Dr. G.H. Jonkers, Burg. Knappertlaan 90-92, 3117 BC Schiedam, The Netherlands.     

从视标增率和记录方法看视力表设计中的核心问题

本研究通过概括视力表视标增率的发展以及目前多数国家正在使用的各种记录方法的特点．来探讨对数视力表设计中的核心问题,如：视标增率（10√10）,记录方法（lgα和5-lgα）,从而阐明缪天荣教授设计的对数视力表在核心问题处理上的合理性和科学性。     

弱视患者远、近视力差异的临床观察

目的  了解弱视儿童近视力和远视力是否存在差异。设计 回顾性病例系列。研究对象 弱视儿童81例（139眼）。方法 对81例初次就诊的弱视患者进行屈光矫正,分别运用标准对数远视力表和标准对数近视力表进行矫正后远、近视力的测量及分析。对所有接受检查的弱视儿童分别按年龄、屈光度和病因进行分组统计分析。主要指标 近视力,远视力。结果 不同病因弱视患者的远近视力比较：屈光不正性弱视、屈光参差性弱视、斜视性弱视患者的平均近视力分别为0.48±0.27、0.47±0.28、0.45±0.30,平均远视力分别为0.46±0.22、0.40±0.20、0.43±0.30,各组的远近视力差异均无统计学意义（P均＞0.05）。不同年龄弱视患者的远近视力比较：3岁～≤5岁组、＞5岁～≤7岁组、＞7岁～12岁组的平均近视力分别为0.41±0.23、0.56±0.29、0.46±0.31,平均远视力分别为0.39±0.18、0.52±0.22、0.42±0.23,各年龄组患者的远近视力差异均无统计学意义（P均＞0.05）。不同屈光度弱视患者的远近视力比较：≤+4.00 D组和＞+4.00 D组平均近视力分别为0.45±0.26、0.48±0.28,平均远视力为0.40±0.30、0.46±0.21,两组屈光度患者的近视力与远视力平均值差异均无统计学意义（P均＞0.05）。结论 本研究结果显示,不同病因、不同年龄段、不同屈光度的弱视患者其远、近视力无明显差异。 （眼科,2013,22： 266-268）     

视力和双眼视力差异对弱视患儿立体视形成的影响

目的探讨双眼视力差异及视力对弱视患儿立体视形成的影响。方法选取4～14岁不伴斜视和其他眼病的弱视患儿160例为试验对象,屈光矫正后进行定性、定量立体视功能检查。比较不同双眼矫正视力差异及视力水平对立体视功能的影响。结果双眼矫正视力差<2行与≥2行组间立体视差异具有显著性,χ2=39.571(P<0.01);双眼矫正视力差≥3行组均无中心凹立体视。106例双眼矫正视力差<2行的患儿中,视力≥0.6组与视力<0.6组间立体视差异具有显著性,χ2=23.910(P<0.01)。视力≥1.0治愈组与正常对照组比较,中心凹和黄斑立体视差异有显著性,χ2=8.617(P<0.01)。结论双眼视力差异大及视力低下是影响立体视形成的重要原因。     

弱视儿童干涉条纹视力测定分析

目的测定分析弱视儿童干涉条纹视力。方法25例(43眼)弱视儿童通过手持式的Heine视网膜视力计进行干涉条纹视力的检查,其结果与最佳矫正视力进行对比。结果43只弱视眼干涉条纹视力平均为4．57±0．2。干涉条纹视力与最佳矫正视力呈正直线相关(r=0．650,P＜0．001),回归方程(?)=0．736x+1．171。中度弱视组干涉条纹视力检查的准确性低于轻度弱视组(X~2=2．471,P=0．166)。结论弱视儿童干涉条纹视力与其最佳矫正视力呈正直线相关,在轻度弱视儿童中两者比较接近。干涉条纹视力的检查可以帮助诊断弱视。     

Assessment of visual acuity in children with trisomy 18

Although 90% of children with trisomy 18 (Edwards syndrome) die in the first year of life, a small proportion survive into the second and third decade. Many do not have associated ocular abnormalities that might affect vision. Measurable visual acuity has not been reported in these profoundly developmentally delayed individuals. Five children with trisomy 18, aged six months to eight years, underwent complete eye examination including assessment of binocular grating acuity with Teller acuity cards and assessment of binocular vernier acuity with vernier cards. All children were nonverbal with profound developmental delay. Binocular grating acuity ranged from 0.9 cycles per degree (cpd) to 2.2 cpd. This represents a reduction of 1.9 to 5.1 octaves (mean 3.5 octaves, SD 1.3 octaves) compared to age matched norms. None of the children responded to any of the vernier offsets, including the largest of 64 minutes of arc. All children with trisomy 18 demonstrated a measurable grating acuity that was well below normal for age, consistent with profound developmental delay.     

Habitual vs optimal distance visual acuity

PURPOSE: The maintenance of a good level of vision is desirable for developmental and social reasons; it is also a requirement that should not be overlooked in the clinical research environment. This study set out to quantify and analyse any difference between 'habitual' (pre-sight test) and 'optimal' (post-refraction) distance visual acuity in an optometric population. It is intended that the outcome of this work will inform not only clinicians but also those undertaking vision research. METHODS: Binocular logMAR visual acuity was determined at 6 m before and after optometric intervention in patients attending optometric practice for a routine sight test. Cases were recorded seriatim but restricted to the 'core' refraction range representative of typical optometric practice; three further exemption criteria included subject illiteracy, the necessity for a non-standard test distance and contact lens wear. Over a 12-month period, two-thirds of patients examined satisfied the study inclusion criteria; it is the clinical data of these 1288 individuals that are described and analysed here. RESULTS: These data provide a quantitative demonstration that an optometric intervention will most likely improve the habitual distance visual acuity of subjects, irrespective of gender, age group, time interval since last test, refractive status and whether or not the subject is a habitual spectacle wearer. The improvement found was typically within one logMAR chart line (<5 letters), being greatest in spectacle-wearing teenagers and in individuals beyond retirement age (increasing to eight letters in elderly habitual non-spectacle wearers); also in non-wearers who left an interval of 2 years or more between sight tests. CONCLUSIONS: Clinical and laboratory-based investigators are advised that a current and optimal refractive correction should be worn by subjects of all ages enrolled in vision-related studies. Refractive defocus may introduce or exaggerate test outcome variability.     

灯箱视力表与电脑视力表临床应用对比研究

目的:通过与灯箱视力表的对比研究了解电脑视力表的临床使用价值。方法:选取初三学生63例(126眼)同时用灯箱和电脑视力表进行远用视力检测,对视力检测值进行配对检验。结果:两种视力表检测值的t检验等于1.2671,P>0.20,两种视力表的检测在统计学上无显著性差异。结论:电脑视力表和灯箱视力表在临床上具有相同的应用价值,可以推广和普及。     

扫描图形视觉诱发电位在视觉发育期儿童中的应用

背景 扫描图形视觉诱发电位(SPVEP)作为一种客观视功能检测技术,可被用于婴幼儿及合作度较差的成年人的客观视力测定.已有研究显示,振幅-视角对数( A-LogVA)回归方法可提高SPVEP推算视力的准确性. 目的 研究SPVEP在视觉发育期儿童中的应用,并比较两种不同的视力推断方法,即振幅-空间频率(A-SP)回归方法和A-LogVA回归方法在儿童,尤其是弱视儿童客观视力评估中的有效性和准确性.方法 选取3～12岁各种原因所致弱视儿童26例26眼为弱视组,同时选取与弱视组儿童年龄相匹配的正常儿童31人为正常组.检测其最佳矫正LogMAR视力,并使用视觉电生理仪检测SPVEP,选用0.99～12.89 cpd的10个不同空间频率正弦调制水平光栅连续刺激视网膜,结果经离散傅里叶分析后采用A-SP回归方法和A-LogVA回归方法计算SPVEP视力,对检测结果行相关性分析. 结果 在正常组,由A-SP回归方法和A-LogVA回归方法计算所得的SPVEP视力与LogMAR视力的相关系数分别为0.600 (P＜0.01)和0.733(P＜0.01),均数差异有统计学意义(F=113.173,P＜0.01).由A-SP回归方法所测得的SPVEP视力(A-SP视力)与LogMAR视力均数差值的绝对值为0.40±0.02,由A-LogVA回归方法所测得的SPVEP视力(A-LogVA视力)与LogMAR视力均数差值的绝对值为0.26±0.02,A-SP视力与A-LogVA视力均数差值的绝对值为0.14±0.02.在弱视组,由A-SP回归方法和A-LogVA回归方法计算所得的SPVEP视力与LogMAR视力的相关系数分别为0.134(P=0.515)和0.456(P＜0.05),均数差异有统计学意义(F=3.433,P＜0.05).A-SP视力与LogMAR视力均数差值的绝对值为0.07±0.05,A-LogVA视力与LogMAR视力均数差值的绝对值为0.12±0.05,A-SP视力与A-LogVA视力均数差值的绝对值为0.05±0.01.在不同视力段,SPVEP视力存在高估或低估现象. 结论 SPVEP可对正常视力及弱视儿童的客观视力进行评估,且A-LogVA回归方法推断所得客观视力更为准确.     

灯箱视力表与Freiburg电子视力表应用对比研究

目的 比较灯箱视力表与Freiburg电子视力表结果的一致性与可重复性,评价Freiburg电子视力表的临床应用价值。设计 诊断性技术评价。研究对象 空军杭州航空医学鉴定训练中心的工作人员86例,平均年龄（26.3±2.1）岁。方法 所有入选者均随机由2位固定检查者分别使用灯箱视力表和Freiburg电子视力表进行检查,两种视力表检查的顺序随机决定。所有检查均在同一房间内完成,房间内亮度小于3 lux。检查距离均为3 m。对不同视力表间与检查者间测量重复性采用配对t检验比较结果的差别并计算相关系数r值。主要指标 使用两种视力表获得的logMAR视力。结果 在检查者一,用灯箱视力表查,被检者logMAR视力为0.19±0.23,Freiburg电子视力表0.20±0.15,两者差值为-0.011±0.141,差异无统计学意义（t=-0.741, P=0.461）,但有显著相关性（r=0.808,P=0.000）。在检查者二,用灯箱视力表查,被检者logMAR视力为0.32±0.25,Freiburg电子视力表为0.20±0.15,两者差值为-0.118±0.151,差异有统计学意义（t=7.191, P=0.000）及显著相关性（r=0.810,P=0.000）。均用灯箱视力表,检查者一、二的差异有统计学意义（F=11.872,P=0.001）,两者显著相关（r=0.938,P=0.000）。而均用Freiburg电子视力表,检查者一、二的差异无统计学意义（F=0.019,P=0.890）,两者显著相关（r=0.986,P=0.000）。结论 Freiburg电子视力表受检查者因素的影响小于灯箱视力表,其在不同测量者间的可重复性优于灯箱视力表。（眼科, 2013, 22: 117-120）     

Distance doubling visual acuity test: A reliable test for nonorganic visual loss

Background  To determine the value of the distance doubling visual acuity test in the diagnosis of nonorganic visual loss in a comparative observational case series. Methods  Twenty-one consecutive patients with nonorganic visual acuity loss and 21 subjects with organic visual loss as controls were included. Best corrected visual acuity was tested at the normal distance of 5 meters using Landolt Cs. The patient was then repositioned and best corrected visual acuity was tested with the previous optotypes at double the distance via a mirror. Results  Nonorganic visual acuity loss was identified in 21 of 21 patients. Sensitivity and specificity of distance-doubling visual acuity test in functional visual loss were found to be 100% (CI; 83%–100%) and 100% (CI; 82%–100%), respectively. Conclusion  Distance doubling visual acuity test is widely used to detect nonorganic visual loss. Our results show that this test has a high specificity and sensitivity to detect nonorganic visual impairment.     

福州市21952名学龄前儿童视力调查

目的探索学龄前儿童视力低常状况,及弱视患病率,为临床治疗提供依据.方法对福州市3～7岁21952名学龄前儿童进行视力普查,将单眼或双眼视力低于1.0者,通知到门诊复查,将矫正视力＜0.9,定为弱视.结果视力低常与年龄密切相关,患病率14.35%,其中男14.11%,女14.58%;弱视患病率3.38%,各年龄组弱视患病率差异无显著性(P＞0.05);视力低常者屈光不正分布远视81.96%,近视8.43%,混合散光9.61%,三者差异有显著性.结论学龄前儿童年龄越小,视力低常率越高;各年龄组弱视患病率无差异;对3～4岁儿童进行弱视诊断时应注意年龄因素.     

近视性离焦对静态视力和动态视力的影响

背景光学离焦对静态视力能产生明显的影响,但是对动态视力的影响尚未见报道。目的研究近视性离焦对静态视力和动态视力影响的差异及其机制。方法研究纳入40名志愿者,包括20名平均年龄（27．40±1．64）岁的成人和20名平均年龄（11．70±1．49）岁的儿童。受检眼排除眼科疾患,最佳矫正视力≥1．0D,散光≤0．75D,双眼屈光参差〈1．50D。受检眼在远用屈光全部矫正的基础上分别加戴＋1．00、＋1．50、＋2．00、＋2．50D的正透镜进行离焦,使用自制的DVA-I动态视力测试仪和静态视力表测试受试者的动态视力和静态视力。结果成人组和儿童组的静态视力和动态视力均随着离焦度的增加而下降,4种离焦度的总体差异均有统计学意义（F=506．907,P=0．000）;成人组和儿童组在各离焦度的动态视力与静态视力间的比较差异均无统计学意义（P〉0．05）;线性回归分析表明,静态视力或动态视力与离焦度间均呈阳性相关（R2=0．819,t=26．720,P=0．000;R2=0．826,t=27．420,P=0．000）;离焦度与静态视力的斜率和截距均明显陡于离焦度与动态视力的斜度和截距（F=34．180,P=0．000;F=1005．560,P=0．001）。结论等量离焦对静态视力和动态视力的影响不同,推测动态视力不仅与屈光系统有关,还可能与其他影响因素有关。     

Assessment of visual acuity by evoked potential recording: Ambiguity caused by temporal dependence of spatial frequency selectivity

The spatial-frequency selectivity of pattern evoked potentials depends on the stimulus repetition rate: responses to low spatial frequencies are emphasized by stimulating at 16–20 Hz, while responses to high spatial frequencies are emphasized at 5–8 Hz. These findings are consistent with the suggestion that pattern EP's are a mixture of pattern responses and responses to local flicker. To a first approximation the “local flicker” responses resemble EP's produced by flickering a light similar to the patterned stimulis in all respects except for absence of pattern. Any developmental changes in the temporal tuning of pattern responses and/or local flicker responses might distort the results of studies in which pattern EP's have been used as an index of either (a) the development of visual acuity or (b) acuity changes due to visual deprivation. Methods of minimizing this problem are suggested.     

白内障患者术后F-VEP、F-ERG检查预测中心视力的评价

目的：评估F－VEP和F－ERG在白内障患者超声乳化人工晶状体植入术后中心视力预测中的价值。方法：对1062眼白内障患者术前使用国产泰克公司TGS－150型眼电生理仪分别行F－VEP和F－ERG检查，比较分析单纯F－VEP异常，F－ERG异常，F－VEP和F－ERG均异常或正常的白内障术后中心视力情况，结果：二项指标结果均正常者976眼，其中术后中心视力≥0．8者920眼（94．42％），≤0．3者78眼（7．99％），F－VEP异常者45眼，术后中心视力≤0．3者6眼（13．3％），F－ERG异常者33眼，术后中心视力≤0．3者16眼（48．5％），二项指标均异常者8眼，术后中心视力≤0．3者5眼（62．5％）。结论：F－VEP和F－ERG对白内障术后的视功能预测有客观性和有效性，在本研究中F－ERG对预测白内障术后中心视力有一定价值。     

近视儿童在低对比度状态下视敏度的表达

目的 通过测量近视儿童的对比度视力,研究近视儿童对比度下降对视敏度的变化规律,了解其内在差异,探讨相关的影响因索 方法 横断面研究,76名9-16岁的近视儿童全矫后,以多功能视力测试仪MFVA -100测量4种对比度下的(100％、25％、10％、5％)视力.人选的近视儿童的近视范围-1.12～-6.00 D,对比度视力使用logMAR视标设计和记录,分析4种对比度下视力的分布规律,以及不同年龄、屈光度、散光对视敏度表达的影响,采用独立样本t检验和单因索方差分析 结果 ①近视儿童在100％、25％、10％、5％对比度下的平均logMAR视力为- 1.007、0.067、0.303、0.558隧着对比度的下降,其logMAR 值逐渐增大(F＝321,P＜0.01).对比度视力在在低对比度区间 呈线性下降②根据4个对比度视力指标,将近视儿童分为两个类别,对比度视力较低的儿童占 30.3％.这类儿童同其余儿童在年龄、屈光度和散光上差异无统计学意义③各年龄组、屈光度组及散光组间的对比度视力差异无统计学意义 结论 近视儿童的对比度视力在低对比度区间呈线性下降.对比度视力不受年龄、低中度近视和散光的影响 其存在的内部差异,推测与近视进展的易感性相关.