Bai Jun-Xing, Bao Li, Liao Meng, Wang Xiao-Yue, Liu Long-Qian
Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu 610041, China.
Sichuan Da Xue Xue Bao Yi Xue Ban. 2013 Mar;44(2):251-4.
To investigate the influence of refractive factors, including axial length, cornea power and astigmatism, and total astigmatism to refractive errors.
Axial length (AL) and cornea power (K) of 295 children (590 eyes) aged 8. 43 years old (4-14 years old) were obtained through IOL-Master, refractive error was measured by retinoscope after cycloplegia. The eyes were divided into 7 groups according to their spherical equivalence (SE). The 7 groups were high myopia, moderate myopia, low myopia, emmetropia, low hyperopia, moderate hyperopia and high hyperopia. AL and cornea parameters of different groups were compared using ANOVA and Pearson's correlation was used to analyze the relationship between SE, AL and cornea astigmatism and total astigmatism respectively.
(1) Of the 7 groups, AL was longest in the high myopia group and shortest in the high hyperopia group. There was a statistically significant difference (P < 0.05) in AL among the 7 groups. (2) High and moderate myopes had the greatest K values and though there was no difference between the 2 groups, they had greater K values compared to other groups (P < 0.05). Moderate hyperopes had the smallest K values which were smaller than any other group except high hyperopia group. (3) SE was negatively correlated with K (r = -0.242, P < 0.001) and positively correlated with cornea astigmatism (r = 0.131, P = 0.001) but had no correlation with total astigmatism. AL was negatively correlated with cornea astigmatism (r = -0.218, P < 0.001) and had no correlation with K and total astigmatism. (4) Multiple linear regression using AL, K and age as independent variable and SE as dependent variable was applied to analyze the relationship of these variables, and the equation was.
The bigger the cornea K value and the longer the AL were, the more myopia the eye was. The study showed that cornea K value of high hyperopes became steeper, indicating that the corneas of high hyperopes tried to compensate for the hyperopic refractive error due to short AL so that the eye can grow toward emmetropization; but the corneas of other groups had the same trend as the AL, which caused myopia or hyperopia together. However, generally speaking, the cornea became steeper as myopia got more severe and flatter as hyperopia more severe.
探讨包括眼轴长度、角膜屈光力和散光以及总散光在内的屈光因素对屈光不正的影响。
通过IOL-Master测量295名年龄8.43岁（4 - 14岁）儿童（590只眼）的眼轴长度（AL）和角膜屈光力（K），用视网膜检影镜在睫状肌麻痹后测量屈光不正。根据球镜等效度（SE）将眼睛分为7组。这7组分别为高度近视、中度近视、低度近视、正视、低度远视、中度远视和高度远视。采用方差分析比较不同组的AL和角膜参数，分别用Pearson相关性分析SE、AL与角膜散光及总散光之间的关系。
（1）7组中，高度近视组的AL最长，高度远视组最短。7组间AL差异有统计学意义（P < 0.05）。（2）高度和中度近视者的K值最大，两组间虽无差异，但与其他组相比K值更大（P < 0.05）。中度远视者的K值最小，除高度远视组外小于其他任何组。（3）SE与K呈负相关（r = -0.242，P < 0.001），与角膜散光呈正相关（r = 0.131，P = 0.001），但与总散光无相关性。AL与角膜散光呈负相关（r = -0.218，P < 0.001），与K及总散光无相关性。（4）以AL、K和年龄为自变量，SE为因变量进行多元线性回归分析这些变量之间的关系，方程为。
角膜K值越大、AL越长，眼睛近视程度越高。研究表明高度远视者的角膜K值变得更陡，提示高度远视者的角膜试图补偿因AL短导致的远视性屈光不正，以使眼睛向正视化发展；但其他组的角膜与AL有相同趋势，共同导致近视或远视。然而，总体而言，近视越严重角膜越陡，远视越严重角膜越平。
