目的：探讨3～6岁学龄前儿童各屈光参数的分布情况及其与等效球镜(SE)的关系，并评估各筛查指标在诊断屈光不正方面的准确性。方法：横断面研究。选取同意完成散瞳验光的3～6岁学龄前儿童，共计791名。测量眼轴长度(AL)、角膜屈光力(K)，小瞳孔下电脑验光和散瞳验光后SE，然后计算角膜曲率半径(CR)及眼轴长度/角膜曲率半径(AL/CR)比值。结果：共纳入791名学生，其中男生400人(50.6%)，女生391人(49.4%)。AL、CR、AL/CR及SE平均值分别为22.62±0.94mm、7.81±0.29mm、2.90±0.09、+1.95±1.31D。AL、CR及AL/CR随年龄的增大而增大； 男生AL及CR显著大于女生(均P<0.001)，男生与女生AL/CR及SE均无差异(P=0.82、0.19)。SE与AL/CR、AL、CR的相关系数分别为-0.86、-0.50、0.16。多元线性回归表明：AL/CR每增加1个单位，SE向近视转变10.91个单位。AL/CR筛查近视的灵敏度为94.44%，特异度为90.46%，约登指数为0.84； 小瞳孔下电脑验光筛查近视的灵敏度为100%，特异度为66.09%，约登指数为0.66； 以AL/CR及AL作为筛查近视的指标绘制受试者工作特征曲线(ROC曲线)，曲线下面积分别为0.967、0.809。结论：在难以进行散瞳验光的大规模群体筛查活动中，AL/CR相对于AL和小瞳孔下电脑验光来说，可以更好地评估屈光状态，且其筛查近视及发现远视储备小于同年龄段儿童的效能也相对更好。

AIM: To investigate the distribution of refractive parameters and theirs correlation with spherical equivalent(SE)in preschool children aged 3 to 6 years, and evaluate the accuracy of each screening index in diagnosing refractive errors.METHODS: Cross-sectional study. A total of 791 preschool children, ranging from 3 to 6 years old, who consented to undergo mydriatic refraction were selected. Axial length(AL), corneal refractive power(K), and SE were measured after microcoria optometry and mydriatic optometry. Additionally, the corneal radius of curvature(CR)and the axial length/corneal radius of curvature(AL/CR)ratio were calculated.RESULTS: A total of 791 students participated in the study, out of which 400(50.6%)were male and 391(49.4%)were female. The mean values for AL, CR, AL/CR, and SE were 22.62±0.94mm, 7.81±0.29mm, 2.90±0.09, and +1.95±1.31D, respectively. AL, CR, and AL/CR increased with age. AL and CR were significantly higher in males than in females(all P<0.001), while there was no statistically significant difference between AL/CR and SE in males and females(P=0.82, 0.19). The correlation coefficients of SE and AL/CR, AL and CR were -0.86, -0.50 and 0.16, respectively. The results of multiple linear regression analysis indicate that for each unit increase in AL/CR, there was a corresponding shift of 10.91 towards myopia in SE. The sensitivity of AL/CR in screening for myopia was 94.44%, with a specificity of 90.46% and a Youden index of 0.84. For screening myopia under microcoria optometry, the sensitivity was 100%, with a specificity of 66.09% and a Youden index of 0.66. The area under the curve was 0.967 and 0.809 when the ROC curves were plotted using AL/CR and AL as indicators for screening myopia, respectively.CONCLUSION: For large group screening activities where mydriatic optometry is not feasible, AL/CR is better for evaluating refractive status and identifying children with myopia and hyperopia reserve that are lower than normal for their age, compared to AL and microcoria optometry.