近视眼SBK术后角膜后表面高度变化及其与角膜生物力学改变的相关性

Changes of Posterior Corneal Elevation in Myopia Undergoing SBK and Its Correlation with Corneal Biomechanical Parameters

目的研究近视眼前弹力层下激光角膜磨镶术(sub-Bowman's keratomileusis,SBK)后角膜后表面高度的变化量及其与角膜生物力学参数变化量的相关性。方法选择行SBK术的近视眼患者44位(共88眼),分别在术前、术后1周、术后1个月及3个月应用Pentacam眼前节分析系统测量角膜后表面高度值,取中央点数值。应用眼反应分析仪(ocular response analyzer,ORA)测量角膜生物力学参数角膜滞后量和角膜阻力因子。结果近视眼SBK术后与术前角膜后表面高度值的差异没有统计学意义,而角膜滞后量、角膜阻力因子术后较术前低,差异有统计学意义。术后1周、1、3个月的角膜后表面高度变化量分别为-0.91±2.04、-0.85±1.92、-0.98±1.65μm。角膜后表面高度的变化量与角膜滞后量、角膜阻力因子变化量的相关性也没有统计学意义。结论近视眼SBK术后角膜生物力学结构受到一定程度的破坏,但角膜后表面中央形态尚未受到影响并保持稳定。

Objective To evaluate the changes of posterior corneal elevation in myopia undergoing sub - Bowman＇s keratomileusis （SBK） and its correlation with corneal biomechanical parameters. Methods Totally 44 myopic patients （88 eyes） having SBK were recruited. The posterior corneal elevation at the center piont was measured using the Pentacam preoperatively and 1 week, 1 month, 3 months postoperatively. Corneal hysteresis （CH） and corneal resistance factor （CRF） were obtained from ocular response analyzer （ORA） at the same time as above. Results The mean changes of the posterior corneal elevation were -0.91 ±2.04, -0.85 ±1.92 and -0. 98± 1. 65μm at 1 week, I month, 3 months after surgery respectively, and the changes were not statistically significant. Both CH and CRF were decreased after surgery,and the changes were statistically significant. There was no significant correlation between the changes of posterior corneal elevation with that of CH and CRF. Conclusion The corneal biomechanical properties of myopic eyes were decreased after SBK, but the posterior corneal shape at the center was not been influenced and keeped stable.