Lea Symbols视力表在42～78个月儿童视力检查中的重复测量可信度分析

目的：探讨Lea Symbols视力表在学龄前儿童视力检查中的重复测量可信度。方法：横断面研究。 2017年4-5月对泉州市泉港区实验幼儿园的250名42～78（61.9±10.3）个月的学龄前儿童进行全面 的眼科检查,使用Lea Symbols视力表重复测量右、左眼的单眼远视力,采用LogMAR记录法记录 视力值。采用Bland-Altman分析、加权Kappa检验、组内相关系数3种统计分析方法衡量2次测量之 间的重复测量可信度。结果：3种分析方法均显示Lea Symbols视力表在学龄前儿童视力检查中的重 复测量可信度较好,2次测量间视力的差值94.3%在1行以内,2次测量的视力值之间的相关性较高 （r=0.753,P<0.001）。在139名屈光正常儿童中,2次测量的视力值（LogMAR）平均相差0.014。在 139名屈光正常儿童中,视力与月龄的相关性是显著的,月龄越大视力越好（r第1次=-0.335,P<0.001; r第2次=-0.424,P<0.001）;性别对可重复性没有影响（P=0.197）。结论：Lea Symbols视力表可用于 中国42个月及以上学龄前儿童的视力检查,可以在临床视力检查中推广使用。     

Comparison of preschool vision screening tests as administered by licensed eye care professionals in the Vision In Preschoolers Study

PURPOSE: To compare 11 preschool vision screening tests administered by licensed eye care professionals (LEPs; optometrists and pediatric ophthalmologists). DESIGN: Multicenter, cross-sectional study. PARTICIPANTS: A sample (N = 2588) of 3- to 5-year-old children enrolled in Head Start was selected to over-represent children with vision problems. METHODS: Certified LEPs administered 11 commonly used or commercially available screening tests. Results from a standardized comprehensive eye examination were used to classify children with respect to 4 targeted conditions: amblyopia, strabismus, significant refractive error, and unexplained reduced visual acuity (VA). MAIN OUTCOME MEASURES: Sensitivity for detecting children with > or =1 targeted conditions at selected levels of specificity was the primary outcome measure. Sensitivity also was calculated for detecting conditions grouped into 3 levels of importance. RESULTS: At 90% specificity, sensitivities of noncycloplegic retinoscopy (NCR) (64%), the Retinomax Autorefractor (63%), SureSight Vision Screener (63%), and Lea Symbols test (61%) were similar. Sensitivities of the Power Refractor II (54%) and HOTV VA test (54%) were similar to each other. Sensitivities of the Random Dot E stereoacuity (42%) and Stereo Smile II (44%) tests were similar to each other and lower (P<0.0001) than the sensitivities of NCR, the 2 autorefractors, and the Lea Symbols test. The cover-uncover test had very low sensitivity (16%) but very high specificity (98%). Sensitivity for conditions considered the most important to detect was 80% to 90% for the 2 autorefractors and NCR. Central interpretations for the MTI and iScreen photoscreeners each yielded 94% specificity and 37% sensitivity. At 94% specificity, the sensitivities were significantly better for NCR, the 2 autorefractors, and the Lea Symbols VA test than for the 2 photoscreeners for detecting > or =1 targeted conditions and for detecting the most important conditions. CONCLUSIONS: Screening tests administered by LEPs vary widely in performance. With 90% specificity, the best tests detected only two thirds of children having > or =1 targeted conditions, but nearly 90% of children with the most important conditions. The 2 tests that use static photorefractive technology were less accurate than 3 tests that assess refractive error in other ways. These results have important implications for screening preschool-aged children.     

A computerized resolution visual acuity test in preschool and school age children

AIM: To study if one of the two molecules could lead to a lower number of follow up visits and intra-vitreous injection (IVI) with the same efficacy. METHODS: ELU (or “elected” in French) study is a retrospective study conducted in real life in patients presenting suboptimal response after ranibizumab IVI (phase 1) and secondary switched to aflibercept (phase 2). The number of follow up visits and IVI were compared in both phases. Visual acuity (VA) evolution and “switching” reasons were secondary analyzed. RESULTS: We retrospectively included data of 33 patients (38 eyes) with age-related macular degeneration (AMD; mean age: 77±7.7y). The number of monthly follow up visits [Median (Q1; Q3)]: was significantly lower with aflibercept (phase 2), respectively 1.0 (0.81; 1.49) visits in phase 1, versus 0.79 (0.67; 0.86) visits in phase 2. The median number of monthly IVI also significantly decreased in phase 2, respectively 0.67 (0.55; 0.90) IVI in phase 1, versus 0.55 (0.45; 0.67) IVI in phase 2. The mean VA evolution (VA final-VA initial) was similar in both phases, (P>0.05). Whatever the reason for “switching” (loss of efficacy, tachyphylaxis, tolerance problems), there was no incidence on VA evolution over the time. CONCLUSION: Our results show that switching from ranibizumab to aflibercept in “suboptimal” patients, significantly reduced the number of follow up visits and IVI, with a comparable efficacy. This decrease in visit number could improve patients’ quality of life and reduce surgical risk by reducing the number of injections.     

两种视力表检查89位学龄前儿童视力的对比研究

目的比较学龄前儿童Lea Symbols与Tumbling E两种视力表的检测率、单眼视力值．建立3。4周岁儿童正常的视力值。方法招募温州市区29—53月龄的89名学龄前儿童，入选标准是身体一般情况良好。智力发育正常，除屈光不正外无其他眼病。以随机顺序用两种视力表检查儿童单眼视力，用间插的logMAR记分方法记录结果。招募23名成人志愿者，分别用两种视力表检查单眼视力．获得两者之间的换算关系。结果成人44眼Lea Symbols的平均视力比Tumbling E高0．02logMAR。89名儿童Lea Symbols视力表的检测率为88％．而Tumbling E视力表的检测率为65％，统计学分析两者差异有显著性（P〈0．01）。60位儿童中115眼能同时配合查Lea Symbols与Tumbling E,Lea Symbols的平均视力为0．17±0．09．Tumbling E的平均视力为0．25±0．09．两者作配对t检验差异具有显著性（P〈0．01）。两种视力表视力相关性高（r=-0．73，P〈0．01），两种视力表视力差值不随视力水平的改变而变化（P=-0．60）。正常屈光状态下儿童Lea Symbols 平均视力0．16±0．07（120眼）。Tumbling E的平均视力0123±0.07（91眼）。结论Lea Symbols视力表和Tumbling E视力表是测量视力可靠且有效的方法．检查4周岁以下儿童的视力时首选Lea Symbol视力表。与Tumbling E视力表相比，Lea Symbol视力表过高估计视力．原因可能在于两种视力表的不同设计以及儿童的认知水平差异。     

Visual acuity results in school-aged children and adults: Lea Symbols chart versus Bailey-Lovie chart.

PURPOSE: To compare visual acuity results obtained using the Lea Symbols chart with visual acuity results obtained with the Bailey-Lovie chart in school-aged children and adults using a within-subjects comparison of monocular acuity results. METHODS: Subjects were 62 individuals between 4.5 and 60 years of age, recruited from patients seen in five optometry clinics. Each subject had acuity of the right eye and the left eye tested with the Lea Symbols chart and the Bailey-Lovie chart, with order of testing varied across subjects. Outcome measures were monocular logarithm of the minimum angle of resolution (logMAR) visual acuity and inter-eye acuity difference in logMAR units for each test. RESULTS: Correlation between acuity results obtained with the two charts was high. There was no difference in absolute inter-eye acuity difference measured with the two acuity charts. However, on average, Lea Symbols acuity scores were one logMAR line better than Bailey-Lovie acuity scores, and this difference increased with worse visual acuity. CONCLUSIONS: The Lea Symbols chart provides a measure of inter-eye difference that is similar to that obtained with the Bailey-Lovie chart. However, the monocular acuity results obtained with the Lea Symbols chart differ from those obtained with the Bailey-Lovie chart, and the difference is dependent on the individual's absolute level of visual acuity.     

Sensitivity of screening tests for detecting vision in preschoolers-targeted vision disorders when specificity is 94%.

PURPOSE: To compare the sensitivity of 11 preschool vision screening tests administered by licensed eye care professionals for the detection of the 4 Vision in Preschoolers (VIP)-targeted vision disorders when specificity is 94%. METHODS: This study consisted of a sample (n = 2588) of 3- to 5-year-old children enrolled in Head Start programs, 57% of whom had failed an initial Head Start vision screening. Screening results from 11 tests were compared with results from a standardized comprehensive eye examination that was used to classify children with respect to the four VIP-targeted vision disorders: amblyopia, strabismus, significant refractive error, and unexplained reduced visual acuity (VA). With overall specificity set to 94%, we calculated the sensitivity for the detection of each targeted vision disorder. RESULTS: With the overall specificity set to 94%, the most accurate tests for detection of amblyopia were noncycloplegic retinoscopy (NCR) (88% sensitivity), the SureSight Vision Screener (80%), and the Retinomax Autorefractor (78%). For detection of strabismus, the most accurate tests were the MTI Photoscreener (65%), the cover-uncover test (60%), the Stereo Smile II stereoacuity test (58%), the SureSight Vision Screener (54%), and the Retinomax Autorefractor (54% in year 1, 53% in year 2). The most accurate tests for detection of significant refractive error were NCR (74%), the Retinomax Autorefractor (66%), the SureSight Vision Screener (63%), and the Lea Symbols VA test (58%). For detection of reduced VA, the most accurate tests were the Lea Symbols Distance VA test (48%), the Retinomax Autorefractor (39%), and NCR (38%). CONCLUSIONS: Similar to the previously reported results at 90% specificity, the screening tests vary widely in sensitivity with specificity set at 94%. The rankings of the sensitivities for detection of the 4 VIP-targeted vision disorders are similar to those with specificity set to 90%.     

Children unable to perform screening tests in vision in preschoolers study: proportion with ocular conditions and impact on measures of test accuracy

PURPOSE: To examine the relative prevalence of ocular conditions among children who are unable to perform preschool vision screening tests and the impact on measures of screening test performance. METHODS: Trained nurse and lay screeners each administered a Lea Symbols visual acuity (VA) test (Good-Lite, Inc., Steamwood, IL), Stereo Smile II test (Stereo Optical, Inc., Chicago, IL), and Retinomax Autorefractor (Right Manufacturing, Virginia Beach, VA), and SureSight Vision Screener (Welch Allyn, Inc., Skaneateles Falls, NY) examinations to 1475 children who later received a comprehensive eye examination to identify amblyopia, strabismus, significant refractive error, and unexplained reduced VA. The outcomes of the examination for children for whom screeners were unable to obtain results (Unables) were compared to the outcomes of children who passed and children who failed each screening test. When estimating sensitivity, specificity, and positive and negative predictive values (PPV and NPV), Unables were classified as either screening failures or screening passers. RESULTS: Less than 2% of children were classified as Unables for each test. The percentage with an ocular condition was at least two times higher for Unables than for screening passers for six of the eight modes of screening (P < 0.05). Considering Unables as screening failures, rather than screening passers, increased the estimate of sensitivity by 1% to 3% (depending on test) and decreased the estimate of specificity by 0% to 2%; PPV decreased by 0% to 4% for most tests, whereas NPV increased by <1%. CONCLUSIONS: Preschool children who are unable to perform VIP screening tests are more likely to have vision disorders than are children who pass the tests. Because < or =2% of children were unable to do each test, referring these children for an eye examination had little impact on the PPV and NPV of the tests, as administered in VIP.     

Lea图形与HOTV字母视力表对3～4.5岁儿童视力检查的比较

目的:比较分析Lea图形与HOTV字母视力表在3~4.5岁学龄前儿童视力检查中的适用情况及视力发育情况。方法:采用调查研究,以随机顺序先后应用两种视力表对广州地区两所幼儿园共133例266眼进行视力检查,视力值及其差异均用logM AR记录方法表示。结果:Lea视力较HOTV视力总体可测率高(96.24%vs92.48%),但差异无统计学意义(P>0.05)。儿童单眼两种视力差异均无统计学意义(右眼t=0.517,P=0.606;左眼t=-0.618,P=0.538)。儿童左右眼之间的视力差异均无统计学意义(Lea视力表:t=0.638,P=0.525;HOTV视力表:t=-0.897,P=0.372)。男性儿童的两种视力均优于女性儿童,但差异无统计学意义(均P>0.05)。3岁、3.5岁、4岁、4.5岁四个年龄组单眼的两种视力检查结果显示,儿童的视力随年龄增长逐渐提高,但四个年龄组间Lea视力差异无统计学意义(右眼:F=2.662,P=0.052;左眼:F=1.850,P=0.143),HOTV视力差异具有统计学意义(右眼:F=4.518,P=0.005;左眼:F=3.893,P=0.011)。结论:两种视力表都适合于3~4.5岁学龄前儿童的视力筛查;3~4.5岁儿童单眼的两种视力结果相似;视力发育与眼别、性别均无关;年龄大于3岁的儿童基本都可以接受主观视力检查,且在学龄前早期主观视力发育较快。     

Threshold visual acuity testing of preschool children using the crowded HOTV and Lea Symbols acuity tests

PURPOSE: To compare the testability and threshold acuity levels for very young children on the crowded HOTV logMAR distance visual acuity test presented on the BVAT apparatus and the Lea Symbols logMAR distance visual acuity chart. METHODS: Subjects were 87 Head Start children from age 3 to 3.5 years. Testing consisted of binocular pretraining at near using a lap card as needed, binocular pretraining at 3 m, and threshold testing for each eye. The testing procedure, adapted from the Amblyopia Treatment Study, presented optotypes until the child was unable to correctly name or match three of three or three of four optotypes of a given size. Threshold acuity was the smallest size for which at least three optotypes were correctly identified. RESULTS: Both near and distance pretraining were completed by 71% of children for HOTV and by 75% for Lea Symbols (P =.39). The distribution of threshold acuities differed between the two tests. For the 69 eyes of 53 children who were successfully tested with both optotypes, results from the crowded HOTV acuity test were on average 0.25 logMar (2.5 lines) better than those from the Lea Symbols acuity test (P <.001). CONCLUSIONS: The proportion of children between 3 and 3.5 years of age whose monocular visual acuity could be assessed was high and was similar for the two charts tested. Crowded HOTV acuity results were better on average than results using Lea symbols. The different formats of the two tests may explain the observed differences in threshold acuity level.     

Using the KM visual acuity chart for more reliable evaluation of amblyopia compared to the HVOT method

PURPOSE: To evaluate a new letter matching visual acuity (VA) chart (the KM chart) for children aged 5-7 years, designed as a Monoyer-based chart, in order to obtain a better consistency between school and preschool VA recordings. METHODS: Visual acuities were assessed using three methods: the HVOT, KM and Monoyer charts. Comparisons were made between the KM method versus the HVOT and Monoyer methods, respectively. Children with normal vision and with different degrees of amblyopia were investigated. RESULTS: Visual acuity levels appeared significantly higher in children with amblyopia when tested with the HVOT chart than when tested with the KM chart. Visual acuities obtained with the Monoyer and KM methods were comparable. The difference between the Monoyer and KM methods on the one hand, and the HVOT method on the other, can be explained by the fact that the HVOT chart elicits less crowding effect than the other two charts. CONCLUSIONS: Visual acuity in children with amblyopia might be overestimated if the HVOT test alone is used to assess vision. Use of the HVOT chart, therefore, should be restricted to the 3.5-4.5 years age group, for whom the KM chart is somewhat too difficult. In our opinion the KM chart should be preferred for use with older preschool children because it shows good consistency with the Monoyer chart.     

Visual acuity screening versus noncycloplegic autorefraction screening for astigmatism in Native American preschool children.

INTRODUCTION: Visual acuity screening (VAS) is less reliable in preschoolers than in school-aged children as a means of detecting significant refractive error. We wished to compare the effectiveness of VAS with the effectiveness of an objective method, noncycloplegic autorefraction screening (NCARS), in detecting the presence of significant astigmatism warranting spectacle correction. METHODS: We examined 245 Native American Head Start registrants aged 3 to 5 years. We attempted to obtain uncorrected visual acuity using Lea Symbols logMAR Chart (Precision Vision Inc, Villa Park, Ill), noncycloplegic autorefraction using the Nikon Retinomax K-plus (Nikon Corp, Melville, NY), and cycloplegic refraction (CR) on each eye. The VAS failure criterion was either a 2-line acuity difference between eyes or acuity worse than 20/40 in either eye. The NCARS and CR failure criterion was the spectacle correction threshold exceeding the 50th percentile on the basis of a survey of AAPOS members. RESULTS: We completed VAS in 96% of children and NCARS and CR in 100% of children. There was high prevalence (31%) of significant astigmatic refractive error in this sample. Ten subjects who did not permit bilateral visual acuity measurements were scored as having a positive test result. The sensitivity and specificity of VAS were 90% and 44%, respectively. NCARS had sensitivity and specificity of 91% and 86%, respectively. NCARS becomes cost-effective after 1044 children are screened, assuming that the cost of the autorefractor is 300 times the cost of the referral examination. CONCLUSION: VAS offers high sensitivity but suffers from poor specificity. NCARS greatly reduces the number of unnecessary referrals. In this population, NCARS becomes cost-effective after approximately 1000 children are screened.     

Cost-efficient vision screening for astigmatism in native american preschool children

PURPOSE: To design and test a cost-efficient, community-based vision screening program for a population of Native American preschool children in which there is a high prevalence of astigmatism. METHODS: Based on analysis of vision screening and eye examination data from a preschool population with a 33% prevalence of astigmatism, comparative costs to conduct a 1000-child screening program with a target sensitivity of 90% were estimated for photoscreening, noncycloplegic autorefraction, autokeratometry, and Lea symbols distance visual acuity testing. Results of the cost analysis and examination of sensitivity and specificity data from the preschool population led to development of a hybrid screening program of autokeratometry and visual acuity screening with referral thresholds of 2.25 D of corneal astigmatism or inability to read a 20/63 Lea symbols line on two separate attempts. The screening program was prospectively implemented in a community-based screening of a similar cohort of 167 children, and its efficiency was evaluated by comparison to results of cycloplegic refraction. RESULTS: The community-based screening showed 96.8% sensitivity and 79.2% specificity for detecting the presence of refractive astigmatism of 1.50 D or more. CONCLUSIONS: Referring children who have at least 2.25 D of corneal astigmatism or acuity worse than 20/63 on two attempts, provides the high sensitivity and specificity associated with automated keratometry while maintaining an acuity component that can detect other causes of reduced acuity in the absence of astigmatism.     

Screening for amblyogenic factors in preschool children with the retinomax hand-held refractor: do positive children have amblyopia and is treatment efficacious?

PURPOSE: To determine the visual acuity (VA) in a group of preschool children who were true positives for refractive screening (positive group) in order to compare it with the VA of a sample of children without any refractive anomaly (control group); also, to investigate if true-positive treated children can achieve the VA of the control group within what delay. METHODS: Fifty seven children without any refractive anomaly were tested with the VA child chart if the Nidek SCP 670 projector; 47 children presenting with the refractive anomalies were tested with the same chart. A Kruskal Wallis exact test for singly ordered tables were used to compare VA between those groups and a non-parametric Wilcoxon test for paired samples was used to compare pre- and post-treatment VA in 27 children of the positive group. The mean time necessary to achieve the post-treatment VA was calculated. RESULTS: Median VA: 20/20 in the control group, 20/33 in the positive group. The VA difference between the two pre- and post-treatment VA are highly significant. Among the 27 treated children, pre-treatment median VA was 20/50, post-treatment 20/20. The differences between the pre- and post-treatment VA was 9 months. CONCLUSION: The positive group had a significantly lower VA than the control group. In the treated group, treatment initiated at a mean age of 4 years resulted in an increase in VA to that of the control group after an average time of 9 months, encouraging early screening and treatment before VA is measureable in order to shorten this delay.     

学龄前儿童常用视力表的研究进展

学龄前期(3-6岁)是视觉发育的关键时期，及早发现并治疗学龄前儿童视觉问题至关重要。视力表是筛查儿童视觉问题的重要工具，国内常采用标准对数视力表和儿童图形视力表，而国外则常用Lea、HOTV和ETDRS视力表。已经有很多研究报道了这三种视力表在儿童视力检查中的可测性、可重复性及诊断视觉相关问题的敏感性。然而，在国内这三种视力表的应用较为有限，本文就这三种视力表的设计原理、临床中的应用及各自的特点进行综述，以便更好地了解它们在学龄前儿童中的适用性和局限性，从而为未来视力检查方法的选择和改进提供参考。     

Preliminary report: Examination of young children with Lea symbols

BACKGROUND. Lea symbols are highly sensitive for detection of amblyopia in cooperative patients. They are favorable for visual acuity assessment in childhood. Therefore, we assessed age-related normal values and interocular differences of Lea symbol visual acuity. METHODS/PATIENTS. We reexamined 50 out of 193 children aged 21 months to 7 years who came for a routine pediatric examination between January and November 1999. Lea symbol acuity (Lea Symbols Single Symbol Book (LS) and Lea 15-Line Folding Distance Chart (CLS)) and Landolt-C acuity (single (LC) and crowded with 2.6' inter-optotype distance (LC 2.6 )) were measured. A three out of four criterion was used. Strabismus and any organic eye disease were excluded by orthoptic and ophthalmologic examination, consisting of biomicroscopy, ophthalmoscopy, retinoscopy or refractometry, cover test or Hirschberg test and Lang Stereotest. RESULTS. Only 26% of the parents (50 out of 193) accepted an examination in our hospital. In 35 (32) of the 50 children, visual acuity could be measured in both eyes seperately with single (crowded) Lea symbols, while 26 (25) children could be examined in both eyes monocularly with the Landolt-C with single (crowded) optotypes. Except for one 3-year-old boy, all of the children older than 30 months could be tested with single Lea symbols. Lea acuity surpassed Landolt acuity. The difference was about 1.5 lines (1.5 dB) for both the single and the crowded optotypes. In 63% (69%) of the children who could be tested monocularly, LS acuity (CLS acuity) was higher than 0.8 (0.63). 89% (83%) of the children had an interocular difference of maximum 1 line for single (crowded) Lea symbols. CONCLUSIONS. The youngest child whose visual acuity could be assessed with Lea symbols was 23 months old. Almost every child older than 30 months could be tested with Lea symbols. Lea acuity higher than 1 and an interocular difference less than 2 lines is not suspect for amblyopia. Children with a difference of more than one line should be reexamined.     

Clinical usefulness of the baby vision test in young children and its correlation with the Snellen chart

AIM: To investigate the efficacy of a new visual acuity (VA) screening method, the baby vision test for young children. METHODS: A total 105 eyes of 65 children aged 2-8y were included in the study. Acuity testing was conducted using a standardized recognition acuity chart (Snellen visual chart: at 3 m) and the baby vision model assessment. The baby vision device includes a screen, a near infrared camera and a computer. Children were seated at a measured distance of 33-40 cm from a display for testing. VA was estimated according to the highest resolution the children could follow. Decimal VA data were converted to logarithm of the minimum angle of resolution (logMAR) for statistical analysis. The VA results for each child were recorded and analyzed for consistency. RESULTS: The mean VA measured using the Snellen visual chart was 0.62±0.32, and that assessed using the baby vision test was 0.66±0.27. The 95% limit of agreement was -0.609 to 0.695, with 95.2% (100/105) plots within the 95% limits of agreement. VA values of the baby vision test were significantly correlated with those of the Snellen chart (R=0.274, P=0.005). CONCLUSION: The baby vision test can be used as a relatively reliable method for estimating VA in young children. This new acuity assessment might be a valid predictor of optotype-measured acuity later in preverbal children.     

Screening athletes with Down syndrome for ocular disease

BackgroundPersons with Down syndrome are well known to have a high prevalence of vision and eye health problems, many of which are undetected or untreated primarily because of infrequent ocular examinations. Public screening programs, directed toward the pediatric population, have become more popular and commonly use letter or symbol charts. This study compares 2 vision screening methods, the Lea Symbol chart and a newly developed interactive computer program, the Vimetrics Central Vision Analyzer (CVA), in their ability to identify ocular disease in the Down syndrome population.MethodsAthletes with Down syndrome participating in the European Special Olympics underwent an ocular screening including history, auto-refraction, colour vision assessment, stereopsis assessment, motility assessment, pupil reactivity, and tonometry testing, as well as anterior segment and fundus examinations to evaluate for ocular disease. Visual acuity was tested with the Lea chart and CVA to evaluate these as screening tests for detecting ocular disease as well as significant, uncorrected refractive errors.ResultsAmong the 91 athletes that presented to the screening, 79 (158 eyes) were sufficiently cooperative for the examination to be completed. Mean age was 26 years ±10.8 SD. Significant, uncorrected refractive errors (≥1.00 spherical equivalent) were detected in 28 (18%) eyes and ocular pathology in 51 (32%) eyes. The Lea chart sensitivity and specificity were 43% and 74%, respectively, for detecting ocular pathology and 58% and 100% for detecting uncorrected refractive errors. The CVA sensitivity and specificity were 70% and 86% for detecting pathology and 71% and 100% for detecting uncorrected refractive errors.ConclusionThis study confirmed the findings of prior studies in identifying a significant presence of uncorrected refractive errors and ocular pathology in the Down syndrome population. Screening with the Lea symbol chart found borderline sufficient sensitivity and specificity for the test to be used for screening in this population. The better sensitivity and specificity of the CVA, if adjusted normative values are utilized, appear to make this test sufficient for testing Down syndrome children for identifying both refractive errors and ocular pathology.     

Is vision screening in 3-year-old children feasible? Comparison between the Lea Symbol chart and the HVOT (LM) chart

PURPOSE: The aim of this prospective study was to compare visual screening at the age of 3 years with screening at 4 years using two different charts. METHODS: A total of 478 3-year-old children were tested at four child health care centres (CHCCs). Of these children, 440 were tested again at the age of 4 years. A third group, a control group, consisting of 229 children, was examined only at the age of 4 years. All children were tested with both the HVOT chart and the Lea Symbol chart. RESULTS: Testability rates for 3-year-olds were almost the same with the Lea Symbol chart and the HVOT chart (82.8% and 84.8%, respectively). The corresponding rates for the same children tested at 4 years of age were 96.5% and 97.0%, and for the 4-year-olds not previously tested 92.9% and 92.8%. The mean testing time was somewhat shorter for the Lea Symbol chart in all three groups, but the difference was not statistically significant. The difference in the assessment of visual acuity between the two charts was small and less than 1/10th of a line. The positive predictive value was lower at 3 years (58%) than has previously been found at 4 years (74.6%). CONCLUSION: Three-year-old children co-operate well in visual acuity testing. However, the examination time is a little longer and the testability rate is about 10% lower than at 4 years. Both 3-year-old and 4-year-old children can be tested equally well with the HVOT and the Lea Symbol charts.     

The repeatability of best corrected acuity in normal and amblyopic children 4 to 12 years of age

PURPOSE: The main purpose of this work was to measure repeatability of line-by-line logMAR (logarithm of the minimum angle of resolution) acuity in normal and amblyopic children, while adequately controlling for optical defocus. METHODS: The Lea Symbols Chart is a constant-crowding, equal-logMAR increment chart similar in design to the Early Treatment Diabetes Retinopathy Study [ETDRS] chart. LogMAR visual acuity was tested twice in each eye of 32 amblyopic and 11 normal children. Each test commenced with screening in which one of the three central symbols was chosen for identification starting with the 1.0- or 0.9-logMAR line, progressing to every second line until incorrect identification occurred. Symbol-by-symbol presentation then commenced at the logMAR line containing the last correctly identified symbol. The threshold was recorded as the last logMAR line where four of four or four of five correct responses occurred (i.e., line-by-line scoring). Retesting by the same examiner was identical and occurred within the same session. RESULTS: There was no significant difference in repeatability among normal, fellow, or amblyopic eyes. The difference between test and retest thresholds lay between +/-0.10 logMAR in 93% of eyes. The 95% limits of agreement for the difference was +/-0.18 logMAR. Repeatability in eyes tested first did not differ from that in those tested second in either the normal or amblyopic groups. CONCLUSIONS: In the age-group tested, the line-by-line method of threshold scoring compares favorably with previous reports of both line-by-line and interpolated threshold scoring. There was no clinically meaningful difference in repeatability between the normal and amblyopic children tested.