Discrimination of paediatric acuity test optotypes by 6-year-old children

Purpose

To compare the discrimination performance of 6-year-old children for optotypes from six paediatric visual acuity tests and to fit Luce's Biased Choice Model to the data to estimate the relative similarities and bias for each optotype.

Methods

Full data sets were collected from 20 typically developing 6-year-olds who had passed a vision screening. They were presented with single optotypes labelled 6/12 at a distance of 9 m and were asked to identify the optotype using a matching task containing all optotypes from the relevant test. The data were combined to form a confusion matrix for each test and a biased choice model was fitted to the data.

Results

Median correct performance varied from 40% to 100% across optotypes, with the HOTV test having the highest values. Estimates of the similarity of each pair of optotypes indicated equal values for all pairs in the Landolt C, HOTV, Lea numbers and Tumbling E tests. The values differed for the picture tests, that is Lea Symbols and Allen figures. The estimates of bias for each individual optotype also indicated different values with the picture tests.

Conclusions

Previous studies of the threshold acuity of young children and adults have indicated differences in acuity estimates across paediatric tests. A recognition acuity task typically requires resolving the difference information between optotypes. The performance of the 6-year-olds here reveals variance in similarity and bias values for picture tests, particularly for the Allen figures when compared with the Lea Symbols. Ideally, this analysis should be performed when designing new tests, and these results motivate progression from the use of current picture tests to well calibrated letter or number tests at the earliest possible age.     

Comparison of the amblyopia treatment study HOTV and electronic-early treatment of diabetic retinopathy study visual acuity protocols in children aged 5 to 12 years

PURPOSE: To compare two established visual acuity protocols: the Amblyopia Treatment Study HOTV (ATS HOTV) visual acuity protocol and the Electronic-Early Treatment of Diabetic Retinopathy Study (E-ETDRS) protocol, in children aged 5 to 12 years. DESIGN: Prospective cohort study. METHODS: Crowded HOTV optotypes and crowded ETDRS optotypes were presented to 236 consecutive children aged 5 to 12 years using an electronic visual acuity tester (Palm handheld, personal computer, and monitor). Twenty-three percent of the children were classified as amblyopic, 35% as having uncorrected refractive error, 36% as normal, and 6% as other. Visual acuity test results were converted to logarithm of minimal angle of resolution (logMAR) units for analysis. RESULTS: In developmentally normal children (n = 230), testability was 100% for HOTV in 5- to 12-year-olds and 100% for E-ETDRS in 7- to 12-year-olds. The E-ETDRS testing could be completed in 52% of 5-year-olds and in 87% of 6-year-olds. Visual acuity performance was better when measured by HOTV compared with E-ETDRS (median difference 0.06 logMAR [three letters on a chart with five letters/line], P =.0001), and the difference was found in normal eyes, eyes with refractive error, and amblyopic eyes. CONCLUSIONS: The ATS HOTV protocol yields slightly better visual acuity performance compared with E-ETDRS in 5- to 12-year-olds, but on average by less than a logMAR level. This systematic difference is important when a physician changes testing modality as a child matures and should be considered when interpreting the results of recent and ongoing clinical trials in amblyopia.     

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.     

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.     

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。     

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。     

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.     

Sensitivity and specificity of a visual acuity screening protocol performed with the Lea Symbols 15-line folding distance chart in preschool children

PURPOSE: The aim of this study was to assess the feasibility of a visual acuity (VA) test using the Lea Symbols 15-line folding distance chart and its diagnostic validity in detecting VA deficiency in preschool children. METHODS: A group of 149 children aged 38-54 months underwent VA examination performed with the Lea 15-line folding optotype at a distance of 3 metres, according to a test protocol described in the Methods section. After the VA test, a complete ophthalmological examination, including cycloplegic retinoscopy, a cover test and examination of the anterior and posterior segments, was performed on each child in order to detect any VA-threatening ocular abnormality. The Lea Symbols test's sensitivity, specificity, positive and negative likelihood ratios (LR +, LR -) and the receiver operating characteristic (ROC) curve were calculated by means of standard procedures using each VA level of the chart from 0.1 to 1 (1-0 logMAR) as a cut-off point. RESULTS: The Lea Symbols test could be successfully used in 95.9% of the population. The most useful cut-off points for screening preschool children were found to be 0.8 (LR + 5.73, LR - 0.05) or 0.63 (LR + 11.7, LR - 0.23). CONCLUSION: The Lea Symbols test proved to be clinically useful in detecting VA deficiency in preschool children. The choice between the two best performing cut-off levels should be made according to the expected cost-effectiveness of the screening programme.     

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.     

The electronic visual acuity tester: testability in preschool children.

PURPOSE: To evaluate the ability of preschool children to have their threshold visual acuity assessed using a standardized, computer-based letter test. METHODS: Participants were 1195 3.5- to 5-year-old children enrolled in the Vision in Preschoolers Study. Monocular visual acuity was assessed by licensed eye care professionals (optometrists and pediatric ophthalmologists experimented in the examination of children), using the Electronic Visual Acuity tester, which uses the letters H, O, T, and V with a crowded surround. RESULTS: Overall, 99.1% of children passed the training that consisted of identifying the letters H, O, T, and V by naming or matching the letters at 60 cm. Among those who passed the training, 99.6% completed the binocular pretest at 3 m, and 97.6% of those passing the training and the pretest completed monocular threshold visual acuity testing of each eye with the Electronic Visual Acuity tester. Testability increased with age for training (p = 0.03), pretesting (p = 0.04), and acuity testing (p = 0.07). Overall, 93.3% of 3.5-year-olds, 96.7% of 4-year-olds, and 98.8% of 5-year-olds completed training, pretesting, and monocular threshold acuity testing of each eye using standard letter optotypes. CONCLUSION: Using the computer-based Electronic Visual Acuity system, nearly all 3.5- to 5-year-old children can complete monocular acuity testing of each eye.     

Reproducibility of visual acuity assessment in normal and low visual acuity

PURPOSE: To assess the reproducibility of measurements of visual acuity in both the upper and lower range of visual acuity. MATERIALS AND METHODS: The retroilluminated ETDRS 1 and ETDRS 2 charts (Precision Vision) were used for measurement of visual acuity. Both charts use the same letters. The sequence of the charts followed a pseudorandomized protocol. The examination distance was 4.0 m. When the visual acuity was below 0.16 or 0.03, then the examination distance was reduced to 1 m or 0.4 m, respectively, using an appropriate near correction. Visual acuity measurements obtained during the same session with both charts were compared. A total of 100 patients (age 8-90 years; median 60.5) with various eye disorders, including 39 with amblyopia due to strabismus, were tested in addition to 13 healthy volunteers (age 18-33 years; median 24). At least 3 out of 5 optotypes per line had to be correctly identified to pass this line. Wrong answers were monitored. The interpolated logMAR score was calculated. In the patients, the eye with the lower visual acuity was assessed, and for the healthy subjects the right eye. Differences between ETDRS 1 and ETDRS 2-acuity were compared. RESULTS: The mean logMAR values for ETDRS 1 and ETDRS 2 were -0.17 and -0.14 in the healthy eyes and 0.55 and 0.57 in the entire group. The absolute difference between ETDRS 1 and ETDRS 2 was (mean +/- standard deviation) 0.051 +/- 0.04 for the healthy eyes and 0.063 +/- 0.05 in the entire group. In the acuity range below 0.1 (logMAR > 1.0), the absolute difference (mean +/- standard deviation) between ETDRS 1 and ETDRS 2 of 0.072 +/- 0.04 did not significantly exceed the mean absolute difference in healthy eyes (p = 0.17). Regression analysis (|ETDRS 1 - ETDRS 2| vs. ETDRS 1) showed a slight increase of the difference between the two values with lower visual acuity (p = 0.0505; r = 0.18). DISCUSSION: Assuming correct measurement, the reproducibilty of visual acuity measurements in the lower acuity range is not significantly worse than in normals.     

Interobserver agreement for grating acuity and letter acuity assessment in 1- to 5.5-year-olds with severe retinopathy of prematurity.

PURPOSE: To evaluate interobserver test-retest reliability of the Teller Acuity Card procedure for assessment of grating acuity at ages 1, 2, 3.5, 4.5, and 5.5 years, for HOTV letter acuity at 3.5 and 4.5 years, and for Early-Treatment Diabetic Retinopathy Study (ETDRS) letter acuity at 5.5 years in the multicenter study of Cryotherapy for Retinopathy of Prematurity (CRYO-ROP). METHODS: Subjects were the 73 participants in the CRYO-ROP study who had acuity assessed at one or more ages by two of the seven study visual acuity testers as part of a quality control procedure. All subjects had birth weights of less than 1251 g, and all had severe (threshold) ROP in one or both eyes. RESULTS: For sighted eyes, interobserver agreement for grating acuity (across all five test ages) was 0.5 octave or better in 57% of eyes and 1.0 octave or better in 85% of eyes. Interobserver agreement for letter acuity (3.5-, 4.5-, and 5.5-year test ages) was 0.5 octave or better in 71% of eyes and 1.0 octave or better in 93% of eyes. For all eyes (sighted and blind), Kendall rank correlation coefficients (Tau) were 0.86, 0.83, and 0.94 for grating, HOTV, and ETDRS acuity, respectively. Kappa statistics on data from all eyes indicated excellent interobserver agreement for grating, HOTV, and ETDRS acuity (0.73, 0.80, and 0.84, respectively). Interobserver agreement was not related to age or to severity of retinal residua of ROP. CONCLUSIONS: Excellent interobserver agreement for grating acuity measurements and for letter acuity measurements was obtained. Results suggest that with careful training and implementation of quality control procedures, high reliability of visual acuity results is possible in clinical populations of young children.     

Outcome of conventional treatment for adult amblyopia

Purpose

To ascertain whether conventional treatment can improve visual function in adults with amblyopia.

Methods

Sixteen patients aged 21–67 years old were instructed to wear glasses for refractive correction and to patch the non-amblyopic eye for at least 1 h per day. Visual acuity, measured with crowded optotypes for distance and near acuity, was checked every 3 months, and followed for a mean (SD) of 14.1 (4.2) months. Prognostic factors related to the subsequent results, an improvement of 3 or more lines logMAR in distance visual acuity, were evaluated.

Results

Of 16 patients, 5 (31 %) improved 3 or more lines of distance and 5 (31 %) in near acuity. The mean improvement in distance was 2.4 lines logMAR (95 % CI 1.4–3.5) and 2.4 lines logMAR for near acuity (95 % CI 1.5–3.3). Patients aged under 45 years (p = 0.0357) and with severe amblyopia (p = 0.0337), defined as a corrected distance visual acuity of worse than ?0.699 logMAR, were associated with a good response.

Conclusions

Conventional treatment may improve the visual acuity of amblyopic eyes even in adult patients.     

Comparison of visual acuity levels in pediatric patients with amblyopia using Wright figures, Allen optotypes, and Snellen letters.

PURPOSE: To compare and correlate the clinical performance of Wright figures in visual acuity assessments of pediatric patients with amblyopia to those obtained through Allen cards and Snellen letters. SUBJECTS AND METHODS: Best-corrected visual acuity of 26 amblyopic children were measured with the Wright figures(c), Snellen letters, and isolated Allen optotypes, respectively. Amblyopia was defined as two lines of visual acuity difference or a visual acuity level of 20/30 or lower as determined by Snellen chart. The results were evaluated for statistical intergroup differences using the Wilks' Lambda multivariate analysis of variance and for correlation using the Pearson correlation coefficient test. RESULTS: The mean age of the subjects was 8.27 +/- 2.46 years (range: 5 to 15 years). The mean logMAR values for the Wright figures(c), Snellen letters, and Allen optotypes were 0.40 +/- 0.20, 0.47 +/- 0.23, and 0.29 +/- 0.28, respectively. When compared with Snellen letters, the Wright figures correlated to a higher degree ( r = 0.46, P < 0.001) than Allen optotypes ( r = 0.67, P < 0.001). With a visual acuity of 20/40 or worse on Snellen letter testing, the sensitivity of Wright figures(c) and Allen cards in diagnosing amblyopic eyes was 87.0 and 56.5%, respectively ( P = 0.016). CONCLUSIONS: Wright figures, designed primarily to evaluate the vision in the preliterate pediatric population, correlate more closely to Snellen letters and have a higher rate of correctly identifying amblyopia than isolated Allen optotypes in pediatric patients.     

婴幼儿主观认知视力可测性年龄发生与视力发育的探讨

目的探讨婴幼儿主观认知视力可测性年龄的发生以及视力随月龄增长的变化规律。方法采用横断研究设计。以随机顺序对264名正常婴幼儿用带围栏的HOTV视频和由电脑控制的闭路式强化优先注视法（COPL）进行单眼视力检测及影响因素调查。采用配对t检验、独立样本t检验、Pearson相关、直线回归及Logistic回归对数据进行分析。结果26％的婴幼儿自24月龄开始接受主观认知视力检测,至46月龄时,已达到100％;24月龄右眼和左眼的平均主观视力分别为4．86＋0．05和4．881-0．08,至46月龄时均达5．0。左右眼间主观视力值比较,差异无统计学意义,男女间的主观视力值差异无统计学意义。主观视力与月龄呈正相关关系（r=O．526,P〈0．01）,主观视力（Y）与月龄（X）之间的直线回归方程为Y_4．699＋0．006X。应用Logistic回归分析,发现母亲教育背景（B=0．460,P=0．05）、A＇JL受教育程度（B=0．386,P〈0．01）对主观视力检测配合度的影响具有显著性。结论电脑控制的带围栏的HOTV认知视标检测系统为观察婴幼儿主观视力可测性的发生及其演绎提供了一种方法,婴幼儿主观视力检测应根据婴幼儿的年龄、认知水平选择不同的方式进行。     

Symmetric bilateral implantation of a distance-dominant diffractive bifocal intraocular lens

PURPOSE: To assess visual results after symmetrical bilateral implantation of a distance-dominant bifocal diffractive intraocular lens (IOL). SETTING: Fernández-Vega Ophthalmological Institute, Oviedo, Spain. METHODS: Fifty patients had bilateral implantation of a distance-dominant diffractive bifocal 447D IOL (Acri.Tec GmbH) in a prospective study. Monocular and binocular best corrected distance visual acuities and best distance-corrected near visual acuity, binocular best distance-corrected intermediate visual acuity, and distance contrast sensitivity under photopic (85 cd/m(2)) and mesopic (5 cd/m(2)) conditions were determined. RESULTS: At the 6-month postoperative visit, the mean binocular best corrected distance acuity and best corrected distance near acuity were 0.02 +/- 0.04 logMAR and 0.04 +/- 0.03 logMAR, respectively. Binocular best corrected distance intermediate visual acuity worsened significantly as a function of the distance of the test: from 0.04 +/- 0.03 logMAR at 33 cm to 0.21 +/- 0.08 logMAR at 70 cm (P<.01). Contrast sensitivity was within normal limits under photopic and mesopic conditions. Binocular contrast sensitivity was statistically significantly better than monocular contrast sensitivity at all spatial frequencies under both illumination levels (P<.01). CONCLUSION: Bilateral implantation of the distance-dominant bifocal 447D IOL provided good simultaneous distance, near, and intermediate vision with improved contrast sensitivity under photopic and mesopic conditions.     

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。     

Prospective study of the Acri.LISA bifocal intraocular lens

PURPOSE: To assess the visual results after bilateral implantation of the bifocal Acri.LISA 366D intraocular lens (IOL) (Acri.Tec AG). SETTING: Fernández-Vega Ophthalmological Institute, Oviedo, Spain. METHODS: Eighty-one patients had bilateral implantation of the distance-dominant bifocal Acri.LISA 366D IOL in a prospective study. Monocular and binocular best corrected distance visual acuity and best distance-corrected near visual acuity, binocular best distance-corrected intermediate visual acuity, and distance contrast sensitivity under photopic (85 cd/m(2)) and mesopic (5 cd/m(2)) conditions were determined. RESULTS: At the 3-month postoperative visit, the mean binocular best corrected distance acuity was 0.048 +/- 0.111 logMAR and the mean binocular best distance-corrected near acuity, 0.012 +/- 0.0084 logMAR (both approximately 20/20). The mean binocular best distance-corrected intermediate acuity changed significantly as a function of the distance of the test, from 0.012 +/- 0.084 logMAR (approximately 20/20) at 33 cm to 0.265 +/- 0.099 logMAR (approximately 20/40) at 70 cm (P<.01). Contrast sensitivity was within normal limits under photopic and mesopic conditions. Binocular contrast sensitivity was statistically significantly better than monocular contrast sensitivity at all spatial frequencies under both illumination levels (P<.01). CONCLUSION: The Acri.LISA 366D IOL provided a satisfactory full range of vision; a high level of uncorrected and corrected distance, intermediate, and near acuity; and improved contrast sensitivity under photopic and mesopic conditions.     

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。