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.     

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。     

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）     

Chart memory and visual acuity measurement

BACKGROUND: A small, but statistically significant, improvement has previously been demonstrated when retesting visual acuity within 24 hours. Because letter chart testing procedures are familiar to most adult patients, this improvement may be due to memory of the chart letter subset, rather than increased familiarity with the test procedure. Chart letter subset memory does not appear to have previously been measured directly. METHODS: A letter recognition task was used to measure chart letter subset memory for groups of routine clinical patients. Comparisons were made between assessments after a single acuity measurement and assessments at increasing intervals after a routine examination involving several references to the same letter chart for both eyes. RESULTS: The recognition score for the 'one-minute-after a single acuity measurement group' was an average of 2.5 letters (range 0.7 to 4.7). Low levels of chart letter subset memory were found to persist for 10 days. CONCLUSION: The chart letter subset memory found is consistent with enhanced acuity scores that occur on retesting. Scores appear likely to have a greater chance of enhancement for a second eye measurement when it follows immediately after the first. Similarly, scores at the end of a full examination may be enhanced by memory that is accumulated during multiple measurements for both eyes using the same chart. Chart memory may be acquired when acuity is measured frequently in monitoring the progress of disease. Chart memory, or its loss over time, may contribute to measurement imprecision and associated expansion of the confidence limits for significant change in acuity.     

常用远用视力表的临床价值对照研究

目的:分析《标准对数视力表》与《低视力视力表》对远用视力检查的临床意义及临床价值。方法:随机抽取本院验光部验光患者59例(118眼),每位患者分别进行两种视力表的远用视力检查,然后记录裸眼视力以及矫正视力检查结果,再进行配对设计资料检验。结果:裸眼视力检查t=2.9944,矫正视力检查t=3.5564,P<0.05,两种视力表无论是裸眼视力还是矫正视力在统计学上均有显著性差异。结论:两种视力表的视力检查结果有所差异,裸眼视力相差19.953′视角,矫正视力相差15.849′视角,且低视力专用视力表的均值均小于标准对数视力表。     

儿童图形视力表与Teller视敏锐度卡在婴幼儿视力检测中应用分析

目的 探讨儿童图形视力表、Teller视敏锐度卡在婴幼儿视力检测中的可行性和可靠性.方法 对2010年1～12月在北京同仁医院眼科斜弱视门诊就诊的185例患儿,分别使用儿童图形视力表检测2～3岁患儿59例118只眼,用Teller视敏锐度卡检测5个月至2岁患儿126例252只眼.每2个月龄为一组,共分为10组进行视力检测,并对其检测结果进行分析评估.结果 应用儿童图形视力表检测视力结果:0.1～0.2者为14.41％ (17/118),0.3～0.5者为64.41％ (76/118),0.6者为21.19％ (25/118);应用Teller视敏锐度卡检测视力结果:13 cy/cm为21.43％ (54/252),4.8～9.8 cy/cm为20.63％(52/252),1.3～3.2 cy/cm为42.86％ (108/252),0.86 cy/cm为10.71％ (27/252),0.43 cy/cm为4.37％(11/252).结论 儿童图形视力表、Teller视敏锐度卡是一种安全、快速、经济、有效地婴幼儿视力评估检测系统,较常规检查能更早地发现低于该年龄段视力发育水平的低常视力,同时可以对眼部先天性疾患的婴幼儿低视力进行早期干预并制定跟踪治疗方案.     

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。     

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.     

Eccentric visual acuity in patients with macular disease

A series of cards each containing a two dimensional array of identical Snellen "E's" was used to determine best eccentric visual acuity in patients with macular disease having Snellen visual acuity of 20/70 or worse. Each "full field E" card simultaneously presents the same letter to foveal and parafoveal areas. This test can therefore determine quickly if potentially useful vision is present in any area of the central visual field. In our study of 37 eyes, 70% demonstrated potential visual acuity at least two times better than visual acuity measured by conventional methods, and 20% demonstrated at least a fourfold improvement. This suggests that most patients with macular disease do not spontaneously employ their best remaining area of retina for fixation.     

Habitual visual acuity in a large urban cohort of Western India and factors influencing poor habitual vision

Purpose:The aim of this study was to determine habitual visual acuity (HVA) in a large urban cohort in western India and identify factors associated with poor HVA.Methods:This was a prospective study conducted over 10 days in September 2018 to assess the HVA in individuals attending a 10-day festival in Western India. Participants who volunteered to undergo vision screening and also filled the questionnaire form pertaining to demographic information including their age, gender, address, income, and educational status were included in this study. HVA was recorded with the distance correction that the participants were wearing when they attended the screening. The study evaluated the prevalence of visual acuity 6/6 or <6/6, 6/12, and 6/18 and the factors associated with lower visual acuity.Results:Of the 6300 participants, 1660 (26.3%) were females. Majority of the participants were from urban background (6084, 96.6%) and were of younger age group (18–40 years––3786, 60.1%; 41–60 years––2187, 34.7%; >60 years––327, 5.2%). HVA was recorded as 6/6 both eyes in 4136 (65.6%), at least 6/12 both eyes in 5691 (90.3%), and at least 6/18 both eyes in 5974 (94.8%) individuals. Only 11 patients (0.17%) had VA worse than 6/60 with only 3 patients (0.003%) having bilateral VA <6/60. Older age, female sex, lower education status, and low annual income were significant risk factors for poor HVA.Conclusion:Poor education, lower income, female gender, and old age are significantly associated with poor HVA even in urban Western India despite relatively easy access to affordable eye care facilities.     

视觉诱发电位技术与视力客观评估

对视觉诱发电位技术及其发展历史、现状进行了必要介绍,并结合分析临床法医实践中眼损伤的特点对视觉诱发电位技术在视力评估中的应用进行了综述。     

Marfan's syndrome: a refractive challenge for optometrists

We present an interesting case of a child with Marfan's syndrome with ectopia lentis, who was followed for five years. The changes in refractive and visual findings of this child during this period are discussed. The importance of careful oculo‐visual examination and possible management options in such children are highlighted.     

Visual acuity testability and comparability in Australian preschool children: the Sydney Paediatric Eye Disease Study

Purpose

To establish standardised protocols for vision screening, testability and comparability of three different vision tests were examined in a population-based, cross-sectional sample of preschool children (Sydney Paediatric Eye Disease Study).

Methods

Measurement of presenting monocular distance visual acuity (VA) using the Amblyopia Treatment Study (ATS) HOTV protocol, was attempted by all (1774) children aged≥24 months. In addition, in children aged≥60 months (576), VA was also tested using the logMAR retro-illuminated HOTV or Early Treatment Diabetic Retinopathy Study (ETDRS) linear charts (CSV 1000). Children able to have both eyes tested monocularly were considered.

Results

Testability significantly increased with age for all VA tests. The ATS HOTV with an overall testability of 80% (females: 82%, males: 78%) was the most testable of the VA tests (P<0.0001). In children aged <3 years testability was low (≤47%) rising to≥80% in children aged≥3. In children≥60 months, testability was higher for the HOTV (94%) than the ETDRS (59%) chart. In those that did two VA tests, mean difference of the ATS HOTV compared with the HOTV(CSV) was −0.1, and compared with ETDRS was −0.12 (P<0.0001).

Conclusions

Children aged <3 years had poor VA testability, whereas those 3 years and above were highly testable using the ATS HOTV. The HOTV (CSV) retro-illuminated test was appropriate for children aged >5 years, and may be possible in younger children with early educational exposure. When comparing VA measures using these tests, the higher VA attained using the ATS HOTV, needs to be taken into account.     

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。