近视眼角膜前、后表面不同范围非球面性及其与角膜球差的关系

目的 探讨拟行准分子激光角膜屈光手术的近视患者角膜前、后表面不同范围非球面性(Q值)及其与角膜球差的关系.方法 横断面研究.选取拟行角膜屈光手术的近视及近视散光患者116例(116眼),年龄18～45岁,球镜度- 1.25～-10.75 D,柱镜度0.00～-3.50 D.应用Pentacam眼前节分析系统对角膜前、后表面6、7、8、9 mm直径下的Q值及角膜球差进行测量.采用Pearson直线相关分析角膜前、后表面Q值与球差及其他参数的相关性、以及角膜前、后表面Q值的相关性,采用直线回归分析建立角膜前、后表面相应范围Q值与球差的回归方程 结果 在6～9 mm取值范围下,角膜前表面Q值分别为-0.24±0.09 、-0.29±0.09、-0.33±0.09和－0.39±0.10;后表面Q值分别为-0.12-0.12、-0.21±0.11 、-0.30±0.10和-0.38±0.10.前表面Q值较后表面Q值偏向负值方向,6～8 mm前后表面差异有统计学意义(t=- 10.35、-6.68、-3.46,P＜0.01).6～9 mm取值范围下角膜前、后表面Q值均呈正相关(r=0.30、0.37、0.40、0.42,P＜0.01).0值与球差存在明显的相关性,在6mm角膜直径下,前表面回归方程为SA=0.663Q+0.415,后表面回归方程为SA=0.159Q-0.177,前表面Q值为-0.60时,球差接近零.6～9 mm取值范围下,前表面Q值与与柱镜度均呈正相关(r=0.28、0.27、0.25、0.22,P＜0.05).后表面7～9 mm范围内的Q值与角膜厚度呈负相关(r=-0.18、-0.21、-0.24,P＜0.05)Q值与年龄、性别、眼别无相关 结论 近视眼角膜前、后表面均呈长椭圆形,前表面较后表面的长椭圆形特点更显著.Q值与球差存在正相关关系,Q值越负,球差越小.

Relationship between asphericity and spherical aberration of the human cornea with different corneal diameters

Objective To evaluate the asphericity of the anterior and posterior corneal surfaces in myopic eyes with different corneal diameters. Methods It was a cross-sectional study. One hundred and sixteen eyes of 116 myopic or myopic astigmatism patients were enrolled. The preoperative spherical refraction was -1.25--10.75 D, and the cyclindrical refraction was 0.00-3.50 D. The Q-value and spherical aberration of the anterior and posterior corneal surfaces for different corneal diameters （6, 7, 8, 9 mm） were measured with a Pentaeam. The correlations between Q-value and spherical aberration, corneal refraction and central corneal thickness were investigated using a Pearson correlation, and a linear regression was used to establish the regressione quation of Q-value and spherical abberration. Results The Q6 Q7 Qs Q9 , of the anterior corneal surfaces of the l l6 eyes were-0.24±0.09, -0.29±0.09, -0.33±0.09, -0.39±0.10, respectively; posterior corneal surfaces were -0.12±0.12, -0.21±0.11, -0.30±0.10, -0.38±0.10, respectively. The Q-values of the anterior corneal surfaces were more negative than the posterior corneal surfaces, the differences were significant except the 9 mm （t=-10.35, -6.68, -3.46, P〈0.01）. Positive relationships were found between the Q-value of anterior and posterior corneal surfaces for 6-9 mm corneal diameters （r=0.30, 0.37, 0.40, 0.42, P〈0.01）. For a 6 mm corneal diameter, the regression equation of the anterior corneal surface was SA=0.663Q＋0.415, and the posterior corneal surface was SA=0.159Q-0.177. Positive relationships were also found between the anterior Q-values and cyclinder refractions for 6-9 mm corneal diameters （r=0.28, 0.27, 0.25, 0.22, P〈0.05）. Negetive relationship were found between the Posterior 0 value and corneal thickness for 7-9 mm corneal diameter （r=-0.18, -0.21, -0.24, P〈0.05）.Conclusion Both the anterior and the posterior corneal diameter increased, the Q-values became corneal spherical aberration can provide more designing aspheric ablation. corneal surfaces in myopic eyes were prolate. As the more negative. The relationship between Q-value and valuable instructions for refractive surgeons when