近视人群角膜生物力学特性的变化及其影响因素

Change in corneal biomechanical properties and influence factors in population with myopia

背景角膜屈光手术会对角膜生物力学产生显著影响，然而目前对角膜屈光手术前近视人群的角膜生物力学仍然研究较少，缺乏大样本人群报道。目的使用眼反应分析仪（ORA）分析单纯近视眼角膜生物力学参数，即角膜滞后量（CH）和角膜阻力因子（CRF）的特性及其影响因素。方法采用前瞻性队列研究设计，收集2010年4月至2011年1月在北京同仁医院眼科中心拟行角膜屈光手术的单纯近视患者896例1792眼，按受检眼等效球镜度（SE）不同分为-0．25～〈-3．0D组、-3．0～〈-6．0D组、-6．0～〈-9．0D组、-9．0～〈-12．0D组、-12．0～〈-15．0D组和≥-15．0D组；按受检眼中央角膜厚度（CCT）不同分为〈500μm组、500μm≤CCT〈550txm组、550μm≤CCT〈600μm组和CCT≥600μm组。所有受检眼均经过常规眼科检查；采用ORA测定受检眼CH值和CRF值，比较不同SE组或CCT组间受检眼CH值和CRF值的差异，采用Pearson直线相关分析法评估近视眼CH和CRF的影响因素。结果受检眼CH和CRF值平均为（9．84±1．52）mmHg（1mmHg=0．133kPa）和（10．46±1．71）mmHg。-0．25～〈-3．0D组、-3．0～〈-6．0D组、-6．0～〈-9．0D组、-9．0～〈-12．0D组、-12．0～〈-15．0D组≥-15．0D组受检眼CH值分别为（10．35±1．53）、（10．07±1．55）、（9．81±1．46）、（9．71±1．59）、（9．35±1．55）和（9．234-1．28）mmHg，总体比较差异有统计学意义（F=20．69，P〈0．01），其中-6．0～〈-9．0D组、-9．0～〈-12．0D组、-12．0～〈-15．0D组≥-15．0D组受检眼CH值均明显低于-0．25～〈-3．0D组，差异均有统计学意义（均P〈0．叭），而不同sE组CRF值的总体比较差异无统计学意义（F=0．65，P=0．49）。〈500μm组、500μm≤CCT〈550μM组、550～〈600μm组和≥600μm组受检眼随着CCT的增加CH值和CRF值逐渐增加，总体比较差异均有统计学意义（CH：F=110．99，P〈0．01；CRF：F=84．35，P〈0．01），其中550～〈600μm组和≥600μm组受检眼CH值和CRF值明显高于〈500μm组，差异均有统计学意义（均P〈0．01）。受检眼CH值与SE间呈弱的正相关（r=0．24，P〈0．01），CRF与SE间无明显相关（r=0．03，P=0．20）；受检眼CH值和CRF值与CCT值间均呈中等正相关（r=0．42、0．57，均P〈0．01）；CH和CRF值随着SE、角膜曲率（CC）、CCT的增加而增加，回归方程为CH=-7．87＋0．08SE＋0．16CC＋0．02CCT（R^2=0．26，P〈0．01）和CRF=-11．42＋0．14CC＋0.03CCT（R^2=0．34，P〈0．01），受检者的CH值和CRF值不随年龄和性别的变化而变化。结论近视眼角膜生物力学的改变与CCT、CC和SE有关，其CH和CRF值随着CCT和CC值的增加而增加，CH值与SE之间呈显著正相关。

Background Corneal refractive surgery has significant effects on corneal biomechanical properties. However,there are few study on large scale population with corneal biomechanical properties in the myopic population before corneal refractive surgery. Objective This study was to evaluate the change of corneal biomechanical properties and influence factors in myopic eyes using ocular response analyzer （ ORA）. Methods A prospective cohort study was carried out in Beijing Tongren Eye Center from April 2010 to January 2011. Corneal hysteresis （CH） and corneal resistance factor （CRF） were detected using ORA in 1 792 eyes of 896 myopic subjects who were going to receive corneal refractive surgery under the informed consent. According to different spherical equivalent （SE） the eyes were grouped into -0. 25-〈-3.0 D group,-3.0-〈-6.0 D group,-6.0-〈-9.0 D group, -9.0-〈-12.0 D group,-12.0-〈-15.0 D group and ≥-15.0 D group and according to different central corneal thickness （ CCT）, the eyes were grouped into 〈500 μm group,500-〈550 μm group,550-〈600μm group and ≥ 600 μm group. The CH value and CRF value in different SE groups or different CCT groups were compared, and the factors influencing CH and CRF were analyzed by Pearson correlation analysis. Results The mean CH and CRF value were （ 9.84 ± 1.52 ） mmHg （ 1 mmHg = 0. 133 kPa） and （ 10. 46 ± 1.71 ） mmHg, respectively in the myopic eyes. The CH values were （10.35±1.53）, （10.07±1.55）, （9.81±1.46）, （9.71±1.59）, （9.35±1.55） and （9.23± 1.28） mmHg in the -0.25-〈-3.0 D group,-3.0-〈-6.0 D group,-6.0-〈-9.0 D group,-9.0-〈-12.0 D group, - 12.0- 〈- 15.0 D group and≥- 15.0 D group, respectively, showing a significant difference among the groups （ F = 20.69,P〈0.01） ,and the C H values in the -6.0-〈-9.0 D group,-9.0-〈-12.0 D group,-12.0-〈-15.0 D group and ≥ -15.0 D group were significantly lower than those in the -6.0-〈-9.0 D group,-9.0-〈-12.0 D group （ all at P〈0.01 ）. There was no significant difference in the CRF values among different SE groups （F= 0. 65 ,P= 0.49 ）. CH and CRF values were increasing with the raise of CCT,with evidently differences among the CCT〈500μm group, 500 μm≤ CCT〈550 μm group,550 μm≤ CCT〈600μm group and CCT≥600 μm group （CH：F= 110.99,P〈0.01; CRF：F= 84.35 ,P〈0.01 ） , and the CH and CRF values were significantly higher in the 550 μm ≤ CCT〈600 μm group and CCT≥600 μm group than those in the CCT〈500μm group （all at P〈0.01 ）. CH showed a positive correlation with SE （ r = 0. 24 ,P〈0. 01 ） , and no significant correlation between CRF and SE （ r = 0.03, P = 0.20 ）. The CH and CRF showed the positive correlations with the CCT （ r = 0.42,0.57, both at P〈0. 01 ）. In addition, CH and CRF values increased as the increases of SE ,corneal curvature （CC） and CCT values,with the regression equation of CH = -7.87＋0.08SE＋0.16CC＋0.02CCT （R^2=0.26,P〈0.01） and CRF=-11.42＋0.14CC＋0.03CCT （R^2=0.34,P〈 0.01） ,respectively. The CH and CRF did not change with the age and gender in the subjects. Conclusions Corneal biomeehanical properties including CH and CRF were positively correlated with CCT,CC and SE.