Lombardo Marco, Lombardo Giuseppe, Manzulli Michele, Palombi Marino, Serrao Sebastiano
Vision Engineering, Reggio Calabria, Italy.
J Refract Surg. 2006 Sep;22(7):656-64. doi: 10.3928/1081-597X-20060901-06.
To analyze the influence of specific combinations of corneal high order aberrations on the optical image quality of the cornea before and after photorefractive keratectomy (PRK) for low to high myopia and myopic astigmatism.
Corneal topography was obtained for 80 eyes that underwent PRK using a scanning-spot excimer laser. The eyes were subdivided into three groups according to the preoperative refraction. The topographical data were imported into a custom software program that combined the Zernike high order terms having the same sign and angular frequency up to seventh order for 4-mm and 6-mm pupils, ie, coma and spherical aberrations, and midperipheral and peripheral high order aberrations.
Photorefractive keratectomy induced a significant amount of the root-mean-square (RMS) values of the combinations of midperipheral and peripheral high order aberrations over the smaller pupil size for deeper myopic ablations (P<.05). Over the larger pupil, spherical myopic ablations showed a significant increase (P<.05) of the RMS values of coma and spherical aberrations. In the astigmatism group, the combination of terms having higher angular frequency increased significantly (P<.05) after surgery both over 4-mm and 6-mm pupils.
After surface ablation, ablation depth and profile significantly influence the distribution and contribution of determined combinations of high order aberrations to the overall high order corneal wavefront aberration. Terms having high angular frequency were increased following large myopic correction and wide treatment zone. Quality of the whole corneal optics will be enhanced by designing future ablation profiles to compensate for peripheral high order optical aberrations.
分析对于低至高度近视及近视散光患者，在进行准分子激光原位角膜磨镶术（PRK）前后，角膜高阶像差的特定组合对角膜光学像质量的影响。
使用扫描点准分子激光对80只接受PRK的眼睛进行角膜地形图检查。根据术前屈光度将眼睛分为三组。将地形图数据导入一个定制软件程序，该程序将4毫米和6毫米瞳孔的直至七阶、具有相同符号和角频率的泽尼克高阶项（即彗差和球差，以及中周边和周边高阶像差）进行合并。
对于更深的近视消融，在较小瞳孔尺寸下，准分子激光原位角膜磨镶术导致中周边和周边高阶像差组合的均方根（RMS）值显著增加（P<0.05）。在较大瞳孔情况下，球面近视消融显示彗差和球差的RMS值显著增加（P<0.05）。在散光组中，手术后视4毫米和6毫米瞳孔，角频率较高的项的组合均显著增加（P<0.05）。
表面消融后，消融深度和轮廓显著影响高阶像差的特定组合对整体角膜高阶波前像差的分布和贡献。在进行大度数近视矫正和宽治疗区后，角频率较高的项会增加。通过设计未来的消融轮廓以补偿周边高阶光学像差，可提高整个角膜光学质量。
