两种视力表检查89位学龄前儿童视力的对比研究

A comparison of two charts for 89 preschool children vision examination

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0.02 logMAR。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,TumblingE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0.23±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LeaSymbol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。

Objective To compare testability, monocular visual acuity in preschool-aged children using the Lea Symbols chart and the Tumbling E chart and to establish normal values of visual acuity for three to four years children. Methods Eighty-nine preschool-aged children ranging in age from 29 months to 53 months were recruited from kid-gardens in Wenzhou city. Inclusion criteria were good general health and normal intellectual development, norreal eyes except for refractive errors. Each children was measured monocular acuity tested with the Lea Symbols chart and Tumbling E chart in random order, and outcome measurement was scored using the interpolated logarithm minimum angle of resolution （logMAR）. 23 adult volunteers were enrolled in this study, monocular acuity tested with Lea Symbols chart and Tumbling E chart was calculated for exchange relation of the two charts. Results The mean acuity of 44 adult eyes obtained with Lea Symbols chart on average 0.02 logMAR better than those obtained with Tumbling E chart. Among 89 children the testability of Lea Symbols chart was 88%, but the testability of Tumbling E chart was 65%, there was statistically significant difference （P〈0.01）. 115 eyes of 60 children both cooperated to test with Lea Symbols chart and Tumbling E chart, Mean （±SD） visual acuity obtained with Lea Symbols chart was 0.17 logMAR （±0.09）, those obtained with Tumbling E chart was 0.25 logMAR （±0.09）, paired t-test showed significant difference （P〈0.01）, the correlation between acuity results obtained with two charts was high （r=0.73,P〈0.01）. The visual acuity difference between Lea Symbols and Tumbling E did not change with visual acuity level （P=0.60）. With the normal refractive error, the mean acuity of Lea Symbols was 0.16, SD was 0.07（120 eyes）, the mean acuity of Tumbling E was 0.23, SD was 0.07（91 eyes）. Conclusion The present study suggests Lea Symbols chart and Tumbling E chart are reliable and valid methods of measuring visual acuity and Lea Symbols chart may be the preferred chart for younger than 4-years old children, but may overestimate the absolute acuity score compared with the Tumbling E chart. The reason may be the different designs of the two charts and the different recognition ability of preschool children.