波前像差引导飞秒激光制瓣LASIK术后不同范围角膜高阶像差的变化

Changes in corneal higher order aberration of different ranges after wavefront guided femtosecond laser assisted LASIK

目的比较波前像差引导飞秒激光制瓣LASIK手术前后不同直径范围角膜前、后表面总高阶像差、球差、彗差、三叶草像差变化情况。方法 应用Pentacam眼前节测量分析系统对术前及术后3～6个月行波前像差引导飞秒激光制瓣LASIK的患者24例（48眼）进行检查测量,分别获得角膜中央直径为4mm、6mm范围角膜前表面、角膜后表面、全角膜总高阶像差、球差（Z4^0和Z6^0）、彗差（Z3^-1、Z3^＋1、Z5^＋1和Z5^-1）以及三叶草像差（Z3^＋3、Z3^-3、Z5^＋3和Z5^-3）的RMS值。应用SPSS13.0统计学软件进行数据分析。结果 手术前随着测量范围的增大,除角膜前表面彗差外,角膜前、后表面其余各类像差分布均是增加的,且差异均有统计学意义（均为P〈0.05）。手术后角膜中央直径4mm范围前表面彗差、三叶草增加相对明显,与术前相比均有统计学差异（均为P〈0.05）;后表面各类像差改变均不明显,差异均无统计学意义（均为P〉0.05）;全角膜各类像差均增加,与术前相比差异均有统计学意义（均为P〈0.05）。手术后角膜中央直径6mm范围前表面球差、彗差、三叶草、总高阶像差均增加,与术前相比差异均有统计学意义（均为P〈0.05）,其中彗差增加量与其他类像差增加量相比相对较小;后表面与全角膜各眼科新进展类像差均增加,与术前相比差异均有统计学意义（均为P〈0.05）。手术后角膜中央6mm范围前后表面除慧差外,各类像差增加量均明显较4mm范围大,差异均有统计学意义（均为P〈0.05）。手术后角膜前表面各类像差变化量均较角膜后表面各类像差变化量大。结论 波前像差引导飞秒激光制瓣LASIK手术前后、不同直径范围均以角膜前表面高阶像差变化为主,角膜后表面变化较小。手术后不同直径范围角膜前后表面各类高阶像差变化特点也不同。

Objective To compare changes in corneal higher order aberration （HOA） about the anterior and posterior corneal surfaces of different ranges after wavefront guided femtosecond laser assisted laser in situ keratomileusis （LASIK）, especially for spherical aberrations, coma, trefoil and total HOA. Methods In a retrospective case study,48 eyes of 24 patients underwent wavefront guided femtosecond laser assisted LASIK. Corneal HOA were obtained preoperatively and 3 -6 months postoperatively respectively. The RMS values of total HOA, spherical aberrations （ Z4^0, Z6^0 ）, coma （Z3^-1 ,Z3^＋1 ,Z5^-1 ,Z5^＋1 ） ,trefoil （Z3^-3 ,Z3^＋3 ,Z5^-3 ,Z5^＋3 ） both in the anterior and posterior corneal surface were calculated with the corneal diameter of 4 mm and 6 nun by Pentacam-HR system. The data was analyzed by SPSS 13.0 software. Resultts Before surgery, with the increase of measuring range, the distribution of spherical aberration, trefoil, total HOA increased both in the anterior and posterior corneal surface, there were statistical differences （ all P 〈 0.05）. After surgery,in the 4 mm central cornea diameter, the coma of anterior corneal surface increased relatively apparent （P 〈 0.05 ） ; HOA of posterior corneal surface had no statistical difference compared with preoperative values （P 〉 0.05 ） ; The whole corneal HOA were statistically significant increased （P 〈0.05 ）. In the 6 mm central cornea diameter, the HOA of anterior corneal surface, posterior corneal surface and whole corneal had statistical difference compared with preoperative values （all P 〈 0.05 ） ;Spherical aberration,trefoil increased obviously than coma in anterior corneal surface. All types of HOA in the 6 nun range increased significant obviousty than that in range of 4 mm （ all P 〈0.05 ）. After surgery for posterior corneal surface, the changes of HOA increased obviously smaller than that in anterior corneal surface. Conclusion With the increasing of measurement diameter,the characteristic of changes in corneal HOA are different both in the anterior and posterior corneal surface before and after wavefront guided femtosecond laser assisted LASIK, changes in anterior corneal surface are larger, but in posterior corneal surface are smaller.