Objective: To discuss the correlation between axial length and corneal curvature and corneal spherical aberration in a group of cataract patients with axial length greater than 24 mm. Methods: Retrospective case series. This study comprised 117 (234 eyes) age-related cataract patients. There were 51 men (43.59%) and 66 women (56.41%) with mean age of (69.0±8.7) years (range from 52.0 to 85.0 years). The average axial length was 27.6±1.8 (range from 24.2 to 31.9 mm). We devided them into four groups according to the axial length. A-scan was used to measure the axial length and Pentacam was used to get the corneal curvature and corneal spherical aberration of both anterior and posterior surface. kolmogorov-smirnov test was used to check the normal distribution. ANOVA test was used to compare eachcorneal parameter among different groups. Pearson correlation analysis was used to obtain the correlation of corneal parameters in groups. Results: There were correlations between the axial length and the anterior and posterior corneal curvature (r=-0.213, r=0.174, respectively, P<0.05). No correlation was found between the axial length and anterior or posterior corneal spherical aberration (r=-0.114, 0.055, respectively, P>0.05). Mean values of corneal anterior surface curvature were (45.26±1.60) D (group 1), (44.17±1.45) D (group 2), (44.40±1.99)D (group 3), and (44.53±1.69) D (group 4) respectively. Mean values of corneal posterior surface curvature were(-6.57±0.26)D (group 1), (-6.40±0.24)D (group 2), (-6.41±0.38)D (group 3), and (-6.43±0.26)D (group 4) respectively. There were significant difference of corneal anterior and posterior surface curvature among 4 groups (P=0.004, P=0.001). There was significant difference of corneal curvature of anterior surface in group 1 compared to group 2 and group 3(P<0.01, P=0.01). There was significant difference of curvature of posterior surface in group 1 compared to group 2 and group 3, respectively (P<0.01). Mean values of anterior surface corneal spherical aberration were (2.09±0.53) μm (group 1), (1.90±0.44) μm (group 2), (2.00±0.74) μm (group 3), and (1.78±0.52) μm (group 4) respectively. Mean values of posterior surface corneal spherical aberration were (2.69±1.15) μm (group 1), (2.46±1.16) μm (group 2), (2.92±2.51) μm (group 3), and (2.69±1.13) μm (group 4) respectively. No correlation was found in anterior and posterior surface corneal spherical aberration(P>0.05) among different groups. Conclusions: The eye with a longer axial length have a flatter cornea. Cornea fails to compensate for axial length elongation when the axial length is longer than 28mm. The corneal spherical aberration varies among individuals, which suggests us to do the customized measurement before cataract surgery to make a decision on choosing the aspherical intraocular lens. (Chin J Ophthalmol, 2017, 53: 255-259).
目的： 研究眼轴长度>24 mm的白内障患者不同眼轴长度与角膜曲率和角膜球面像差的相关性。 方法： 回顾性病例系列研究。选取北京大学国际医院眼科年龄相关性白内障患者共117例（234只眼），其中男性51例（43.59%），女性66例（56.41%），年龄52.0~85.0岁，平均（69.0±8.7）岁，眼轴长度（27.6±1.8）mm（范围24.2~31.9mm）。根据A超测得眼轴长度将患者分为4组：第1组为24 mm≤眼轴长度<26 mm，共47只眼，第2组为26 mm≤眼轴长度<28 mm，共100只眼，第3组28 mm≤眼轴长度<30 mm，共55只眼，第4组30 mm≤眼轴长度<32 mm，共32只眼。使用A超测量眼轴长度，Pentacam眼前节诊断分析仪测量角膜前、后表面曲率值，6 mm直径内的前、后表面角膜球面像差值。使用SPSS22.0软件进行统计学分析，采用单样本K-S检验正态性分布，用Pearson相关分析获得年龄与角膜参数、眼轴长度与角膜参数之间的相关性，采用单因素方差分析对各角膜参数在不同眼轴长度分组间进行比较。 结果： 117例（234只眼）白内障患者眼轴长度与角膜前、后表面曲率之间有相关性（r=-0.213，0.174；P<0.05），与角膜前、后表面球面像差之间均无相关性（r=-0.114，0.055；P>0.05）；角膜前表面曲率平均值分别为第1组（45.26±1.60）D，第2组（44.17±1.45）D，第3组（44.40±1.99）D，第4组（44.53±1.69）D；角膜后表面曲率平均值分别为第1组（-6.57±0.26）D，第2组（-6.40±0.24）D，第3组（-6.41±0.38）D，第4组（-6.43±0.26）D。各组间角膜前、后表面曲率的差异有统计学意义（P=0.004、P=0.001）。组间进行两两比较时，第1组的角膜前表面曲率分别与第2组、第3组间差异有统计学意义（P<0.01，P=0.01），第1组的角膜后表面曲率分别与第2组、第3组间差异有统计学意义（P<0.01），而其余各组间差异无统计学意义（P>0.05）；角膜前表面球差平均值分别为第1组（2.09±0.53）μm，第2组（1.90±0.44）μm，第3组（2.00±0.74）μm，第4组（1.78±0.52）μm；角膜后表面曲率平均值分别为第1组（2.69±1.15）μm，第2组（2.46±1.16）μm，第3组（2.92±2.51）μm，第4组（2.69±1.13）μm。组间两两比较时，角膜前、后表面球差在各组间差异均无统计学意义（P>0.05）。 结论： 随着眼轴长度的增加，角膜前表面曲率减小，但眼轴>28 mm后，补偿作用减弱。角膜球差在个体间差别较为明显，需在白内障摘除术前进行个体化测量，从而指导非球面IOL的选择。（中华眼科杂志，2017，53：255-259）.
Keywords: Aberrometry; Axial length, eye; Cataract; Cataract extraction; Corneal topography.