LASIK对远视眼波前像差的影响

Effects of hypermetropic LASIK on ocular wavefront aberrations

目的:探讨准分子激光原位角膜磨镶术(laser鄄in鄄situkeratomileusis熏LASIK)后的远视眼波前像差变化。方法:测量行远视LASIK术后1年以上的56例患者以及23例未做手术的远视对照组的波前像差和角膜地形图,分析4.2mm和6mm瞳孔直径下,全眼、角膜和眼内部的第3～6阶高阶像差的均方根值和Zernike4阶球面像差的变化。结果:4.2mm和6mm瞳孔直径下,远视LASIK组,全眼、角膜和眼内部像差的高阶均方根值和球面像差与手术矫正的屈光度相关(4.2mm的内部球面像差除外)(P<0.05);对照组屈光度与上述各因素无明显相关(P>0.05)。在6mm瞳孔直径下,LASIK矫正3D的远视或远视散光,全眼高阶像差的均方根值增加1倍;并且通过改变角膜前表面的非球面性使其球面像差从正向变为负向。结论:远视LASIK增加了眼的波前像差熏降低了眼的视觉质量。

Objective: To investigate the change of aberrations in patients having undergone hypermetropic laser-in-situ keratomileusis (LASIK). Methods: This study included 56 hypermetropic patients who underwent LASIK (LASIK group) and 23 hypermetropic patients who did not accept LASIC (control group). Aberrations and corneal topography were measured with the Nidek OPD-Scan model ARK-10000. The higher-order root-mean square (HORMS) wave aberrations for combined 3 rd to 6 th Zernike aberration orders and the Zernike spherical aberration co-efficient C at both 4.2 mm and 6.0 mm pupil sizes were calculated. Results: For LASIK group, surgical refractive change correlated significantly with total, corneal and internal HORMS and spherical aberrations (except internal spherical aberration for a 4.2 mm diameter pupil). For the control group, there was no significant correlation of refraction to any of these factors (P=0.17～0.45). For a 3D change in refraction with 6 mm pupils, LASIK doubled the total HORMS aberrations. LASIK changed the sign of spherical aberration from positive to negative by increasing the negative asphericity of the anterior cornea. Conclusion: Hypermetropic LASIK is found to increase the aberrations and decrease the image quality.