单眼高度近视患者眼前节形态学研究

目的 了解高度近视眼眼前节形态的结构特点,探讨高度近视眼与中低度屈光不正眼的眼前节形态是否存在差异.方法 单眼高度近视患者23例（46眼）,年龄（24.1±12.4）岁（范围8～49岁）,屈光参差（8.73±4.73）D（范围1.62～16.75 D）,进行双眼间的对照研究,高度近视眼（屈光不正度数高于-6.00 D）为高度近视组,对侧眼（屈光不正度数在-5.75 D之内）为对照组.用A型生物超声仪测量中央角膜厚度和眼轴长度,Pentacam眼前节三维分析仪测量角膜前后表面曲率（中央区角膜最大与最小子午线角膜曲率的平均值）或曲率半径、角膜前后表面非球面形态（30°范围的平均Q值）、角膜前后表面散光、前房深度、前房角及前房容积.采用SPSS 15.0统计软件,配对t检验用于双眼间的参数比较,直线相关用于两参数间的相互关系分析.结果 高度近视组的眼总散光、眼轴长度及跟轴长度/角膜曲率半径（AL/CR值）分别为（1.43±1.26）D、（27.45±1.63）mm及3.60±0.22;对照组的眼总散光、眼轴长度及AL/CR值分别为（0.93±0.92）D、（24.19±1.41）mm及3.16±0.12,两组比较均有统计学意义（t=-2.539,P〈0.05;t=8.606,P〈0.01;t=8.167,P〈0.01）.高度近视组的角膜前、后表面曲率,角膜前、后表面散光,角膜前、后表面非球面系数Q值,前房深度,前房角及前房容积分别为（44.1±1.8）D、（-6.3±0.3）D,（1.4±1.0）D、（0.3±0.2）D,-0.35±0.13、-0.16±0.18,（3.12±0.30）mm,（38.7±4.2）°及（178±37）mm^3;而对照组的上述参数分别为（44.1±1.8）D、（-6.4±0.3）D,（1.3±0.8）D、（0.4±0.2）D,-0.33±0.10、-0.20±0.19,（3.08±0.32）mm,（38.8±5.8）°及（175±40）mm^3;两组差异均无统计学意义（P〉0.05）.眼轴长度与等效球镜度在高度近视组和对照组均显示了高度线性相关关系（高度近视组r=0.662,P〈0.01;对照组r=0.618,P〈0.01）.在高度近视组和对照组,角膜顶点曲率半径与等效球镜度无相关性（高度近视组r=0.287,P〉0.05;对照组r=0.261.P〉0.05）.结论 高度近视眼与中低度屈光不正眼眼前节形态无明显差异,而眼轴长度存在明显差异,高度近视眼眼轴明显延长.

Biometry of the anterior segment of the eye in unilateral high myopia patients

Objective To investigate the biometric properties of the anterior segment of high myopia eyes, and to determine if there are differences in the ocular biometry of eyes with high myopia and low to moderate refractive errors. Methods Twenty-three patients aged from 8 to 49 years, mean age (24.1±12.4)years]with unilateral high myopia (-6.00 diopters or more) were recruited for the paired study. Fellow eyes with low to moderate refractive errors (within -5.75 diopters) were used as a control group. Anisometropia was (8.73±4.73)D (range from 1.62 D to 16.75 D). The central comeal thickness and axial length (AL) were measured with A-scan ultrasonography and corneal curvature (mean curvature of the maximum and minimum meridian curvature of the central cornea), corneal asphericity (Q value within 30 degrees), corneal astigmatism、anterior chamber depth (ACD), anterior chamber angle (ACA) and anterior chamber volume (ACV) were measured with a Pentacam. Statistical analysis was performed with SPSS software for Windows (version 15.0). A paired t-test was used to evaluate the differences in the parameters between the two eyes and linear correlation was used to describe the correlation between the two variables. A P value of <0.05 was considered statistically significant. Results The high myopia group showed significantly higher ocular astigmatism (1.43±1.26)D vs (0.93±0.92)D], AL (27.45±1.63)mm vs (24.19±1.41)mm]and AL/CR (3.60±0.22 vs 3.16±0.12) than the control group (t=-2.539, P<0.05; t=8.606, P<0.01; t=8.167, P< 0.01, respectively). In the high myopia group, the anterior and posterior corneal curvature, corneal astigmatism and comeal asphericity, ACD, ACA and ACV were (44.1±1.8)D, (-6.3±0.3)D, (1.4± 1.0)D, (0.3±0.2)D, -0.35±0.13, -0.16±0.18, (3.12±0.30)mm, (38.7±4.2)° and (178±37)mm\ respectively; and in the control group, the values were (44.1±1.8)D, (-6.4±0.3)D, (1.3±0.8)D, (0.4± 0.2)D, -0.33±0.10, -0.20±0.19, (3.08±0.32)mm, (38.8±5.8)° and (175±40)mm3 respectively. There were no significant differences between the two groups (P>0.05). Spherical equivalent was positively correlated to AL in the high myopia group and control group (r=0.662, P<0.01; r=0.618, P<0.01, respectively). However, this value was not correlated to the corneal curvature radius (CR) in either group (high myopia group r=0.287, P=0.196, control group r=0.261, P=0.240). Conclusion There are no significant differences in the biometric properties of the anterior segment of the eye between high myopia and low to moderate refractive errors. The AL is the main biometric parameter related to high myopia.