3--6岁儿童睫状肌麻痹后散光变化的矢量分析

Vector analysis of astigmatism with and without cycloplegia in 3-6 years old preschool children

目的对3~6岁学龄前儿童的散光值进行矢量分析，并研究睫状肌麻痹对散光的影响。方法横断面研究。2012年1—10月选取上海市杨浦区3-6岁儿童14116例．其中男孩7310例，女孩6806例。平均年龄（4．0±0．8）岁。采用CanonRK—F1型全自动电脑验光仪对所有儿童行睫状肌麻痹前后的电脑验光，记录全眼散光及轴向；ZeissIOLMaster测量眼轴长度。每例均取右眼进行统计分析。对完成所有检查的13080例有效样本的全眼散光进行Thibos矢量分析，将近视性散光转换为M、Jn和J45。睫状肌麻痹前后的各数据差异采用配对t检验进行统计分析。结果睫状肌麻痹前后，3～6岁儿童主要表现为顺规性散光，特别是在柱镜值≥1．00D的高度散光组，其次为斜轴性散光．最后为逆规性散光。在睫状肌麻痹后，高度散光的比例略有下降，从19．96％降至18．41％；而O．25～0．75D的正常散光比例略有增加，从28．59％增加到33．72％。同时在睫状肌麻痹后，顺规性散光比例增高，逆规性散光和斜轴性散光比例都略有下降。而在高度顺规性散光组中，睫状肌麻痹后全眼散光值下降[（-1．612±0．763）D vs．（-1．457±0．645）D，t=-6．396，P〈0．01），其中主要表现为J0成分的降低，J45成分保持不变。结论睫状肌麻痹对散光也有着一定程度的影响，尤其是对高度顺规性散光。

Objective Analyze astigmatism in 3-6 years old preschool children using vector analysis and to investigate the effect of cycloplegia on astigmatism. Methods In this cross-sectional study, refraction and eye health were examined in 14 116 3-6 years old children （7 310 boys, 6806 girls） in Yangpu District, Shanghai, China, from January 2012 to October 2012. Pre- and post-cycloplegic refractive measurements were taken with an autorefractor （Canon RK-F1, Japan） and axial length was measured with an IOLMaster （Carl Zeiss, Germany）. Of 13 080 eligible children, all the data from the right eyes were analyzed. Measurements of spherocylinder were transposed into M, J0 and J45 components by Fourier transformation. Data were analyzed using a paired t test. Results Astigmatism in preschool children 3-6 years old was mainly with-the-rule （WTR）, especially in the high astigmatism group （HAG, /〉1.0 D）, followed by oblique axis astigmatism, and then against-the-rule （ATR） astigmatism. After cycloplegia, the prevalence of high astigmatism （I〉1.0 D） decreased from 19.96% to 18.41%; the prevalence of normal astigmatism （0.25-0.75 D） increased from 28.59% to 33.72%. Meanwhile, the proportion of WTR astigmatism increased, and ATR astigmatism and the oblique axis astigmatism ratio declined slightly after cycloplegia. Total astigmatism declined only in the high WTR astigmatism group （-1.612±0.763 D vs. -1.457±0.645, t=-6.396,P〈0.01）, mainly for J0 components. The J45 components remained the same before and after eycloplegia. Conclusion Cycloplegia has a slight effect on astigmatism, especially in the high WTR astigmatism group. The astigmatism results for non-cycloplegia may be more important for preschool children when assessing and prescribing for astigmatism.