LASIK术后角膜后表面的改变及其稳定性的影响因素

目的研究准分子激光原位角膜磨镶术(laser in situ keratomileusis,LASIK)后角膜后表面(包括中央和周边区)改变,探索影响其稳定性的因素,为获得理想的术后效果提供新的术前筛选标准。方法本研究入选患者共59例(117眼),屈光不正的等效球镜范围为-2.75～-11.75D,术中和术后无并发症,于术前和术后3个月分别行Pentacam检查。测量角膜后表面各参数的改变,包括中央6mm区角膜后表面最适球面;周边6mm、7mm、8mm、9mm、10mm环区平均角膜后表面曲率半径。结果术后3个月中央6mm区角膜后表面最适球面曲率半径为6.4087±0.3778mm,与术前(6.3037±0.2479)mm相比显著增加(P<0.001),周边6mm和7mm环区平均角膜后表面曲率半径减小,术前为(6.3450±0.2680)mm、(6.4374±0.2563)mm,术后为(6.3190±0.2473)mm、(6.4170±0.2514)mm,差异均有统计学意义(均为P<0.05)。利用(角膜瓣厚度+切削厚度)/术前角膜最薄点厚度分组,百分比>45%组术后3个月中央6mm区角膜后表面BFS曲率半径较术前显著增加(P<0.001),而周边6mm环区平均曲率半径明显减小(P=0.017);百分比<45%组各参数都无明显改变。结论 LASIK术后,中央6mm区角膜后表面变平,周边6mm和7mm环区变凸。"(角膜瓣厚度+切削厚度)/术前角膜最薄点厚度"百分比小于45%者角膜后表面稳定性较好,该百分比可能作为提高术后可预测性的新指标。

Changes of posteriorcorneal surface alter laser in situ keratomileusis and factors that affect its stability

Objective To investigate the changes of posterior corneal surface after laser in situ keratomileusis(LASIK) and factors that affect its stability in order to develop preoperative criteria for better outcome of the procedure. Methods About 59 patients(117 eyes) were enrolled.The spherical equivalent of ametropia was-2.75 D to-11.75 D.No complication was found during and after operation.Pentacam examination was taken before operation and at 3 months after operation.The changes in posterior corneal surface,inc...