674例3~6岁视力低常儿童屈光状态分析

Analysis of refractive state in 674 children aged 3 to 6 years old with subnormal vision

目的 分析3-6岁视力低常儿童的屈光状态分布并探讨不同屈光类型与弱视发生的关系.方法 描述性研究.对674例（1348眼）3-6岁裸眼视力低于正常（3岁≤20/40,4岁≤20/32,5岁及以上≤20/25）儿童进行阿托品散瞳后验光检查屈光状态及矫正视力.分析不同年龄段、弱视眼和非弱视眼的屈光状态分布,不同年龄段屈光参差分布以及屈光参差与弱视发生的关系.不同年龄段屈光分布的构成比及弱视发生率比较采用卡方检验.结果 视力低常儿童中屈光分布以远视为主,近视发生率较低;随着年龄增加,远视所占比例逐渐降低,近视所占比例逐渐增加,差异有统计学意义（χ^2=99.7,P〈0.001）.弱视眼和非弱视眼屈光分布差异有统计学意义（χ^2=20.1,P=0.01）;弱视眼中前3位屈光类型分别为复性远视散光（59.4%）、单纯远视散光（17.8%）和混合性散光（15.8%）,而单纯近视眼中无弱视发生.双眼等效球镜度差值≥1 D时容易引起屈光参差性弱视,并且弱视发生率随屈光参差程度增大而升高（χ^2=62.9,P〈0.001）.结论 学龄前视力低常儿童的屈光状态分布以远视为主,远视性屈光不正、散光、屈光参差等屈光异常更容易引起弱视的发生.

Objective To investigate the distribution of refractive state in children aged 3 to 6 years old with subnormal vision and to analyze the relationship between different refractive types and amblyopia. Methods This was a descriptive study of 674 children （1348 eyes） aged 3 to 6 years old who had subnormal vision （3 years old≤20/40, 4 years old≤20/32, 5-6 years old≤20/25）. Refraction and corrected visual acuity were detected after cycloplegia using 1% atropine ointment. The distribution of refractive errors in cases with and without amblyopia were analyzed. The incidence of anisometropia at different ages and the relationship between anisometropia and amblyopia were studied. The distribution of refractive errors and the incidence of amblyopia were compared by the chi-square test. Results The majority of the children were hyperopic, and myopia rarely occurred. With increasing age, the proportion of children with hyperopia decreased gradually while myopia increased, and the difference was statistically significant （χ^2=99.7, P〈0.001）. There was a significant difference in the distribution of refraction between amblyopic and non-amblyopic eyes （χ^2=20.1, P=0.01）. The first three refractive causes of amblyopia were compound hyperopic astigmatism （59.4%）, simple hyperopia astigmatism （17.8%）, and mixed astigmatism （15.8%）. No amblyopia occurred in the eyes with simple myopia. The incidence of amblyopia was higher when the spherical equivalent difference between the two eyes was or more than 1 diopter. There was a significant increase in the occurrence of amblyopia with increased anisometropia （χ^2=62.9, P〈0.001）. Conclusion The majority of children 3 to 6 years old with subnormal vision have hyperopia. Hyperopia, astigmatism, and anisometropia are prone to cause amblyopia.