调节对儿童屈光构成因素的影响

目的：通过分析调节对儿童屈光构成因素的影响，探讨调节与屈光不正、特别是与近视眼的关系。方法：检测135例（270只眼）儿童睫状肌麻痹前后的前房深度（AD）、晶状体厚度（LT）、玻璃体腔径（VL）、眼轴长度（AL）的变化以及睫状肌麻痹后的屈光状态。对其中136只眼行睫状肌麻痹前后角膜地形图检查。结果：不论远视眼、正视眼还是近视眼在睫状肌麻痹后胶房加深（P＜0．01），晶状体变薄（P＜0．01），玻璃体腔径缩短（P＜0．01），但远视眼睫状肌麻痹后眼轴增长（P＜0．05），近视眼眼轴缩短（P＜0．01）；远视眼睫状肌麻痹后，以角膜中心点中心，直径为3mm的环平均角膜屈光度（MD3，P＝0．009）和角膜曲率K1（P＜0．05）增加；近视眼睫状肌麻痹后除MD3（P＝0．033）、K1（P＜0．05），K2以及以角膜中心点为中心，直径为5mm,7mm的环平均角膜屈光度（MD5、MD7）均降低（P≤0．01）；角膜垂直径线下方的平均角膜屈光度（LMD）大于上方的平均角膜屈光度（UMD）而水平径线颞侧的平均角膜屈光度（LaMD)大于鼻侧的平均角膜屈光度（MMD）（P＜0．01）。结论：调节对眼的几乎所有屈光构成因素有着显著的影响；它本身不仅是传统意义上的晶状体本身屈光度增加，同时还伴有晶状体的相对前移；角膜的非球面性即便是在同一垂直或水平径线上的屈光分布也是非对称的。

Effect of Ocular Accommodation on Refractive Components in Children

Purpose: To study the correlation between ocular accommodation and ametropia, especially myopia by analyzing the effect of accommodation on refractive components in children. Methods: The anterior chamber depth (AD), lens thickness (LT), vitreous chamber length (VL) and ocular axial length (AL) were measured for 135 cases (270 eyes) of children before and after cycloplegia. The corneal shapes of 136 eyes selected from the 270 eyes were studied before and after cycloplegia by a computerized video keratoscope. Results: AD increased (P < 0. 001) while both LT (P < 0. 001) and VL decreased (P < 0. 01) significantly after cycloplegia regardless of their refractive state. However, AL increased for hyperopic eyes (P = 0.027) and decreased for myopic eyes (P = 0. 008) after cycloplegia. For hyperopic eyes, the major keratometer K1 increased (P = 0. 025) while for myopic eyes, the major keratometer Kl (P = 0. 039) and minor keratometer K2 (P = 0. 003) decreased after cycloplegia. Similarly, mean corneal power of zones 3mm (MD3\ 5 mm (MD5) and 7 mm (MD7) decreased dramatically (p < 0. 05) with myopic eyes after cycloplegia, while MD3 ( P = 0. 009) increased with hyperopic eyes. The mean refractive power of the lower half vertical meridian (LMD) is greater than that of upper half (UMD); and the mean refractive power of the lateral half of the horizontal (LaMD) is greater than that of the medial half (MMD). Conclusion: The ocular accommodation has a great influence on refractive components in children. It is not only the process by which the refractive power of the lens is increased. Furthermore, the lens itself moved forward relatively. There is asymmetry of the corneal surface within the same horizontal or vertical meridian. Eye Science 2002; 18; 208 - 213.