Relative Contribution of Central and Peripheral Aberrations to Overall High Order Corneal Wavefront Aberration

Abstract

PURPOSE:To analyze the infl uence of specifi c 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. METHODS: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.JRS0906LOMBARDO.indd 656 JRS0906LOMBARDO.indd 656

LASIK for Myopia and Astigmatism Using the SCHWIND AMARIS Excimer Laser: An International Multicenter Trial

“…Using a 6-mm analysis diameter, they found an increase of 0.09 µm for coma, ϩ0.13 µm for spherical aberration, and 0.17 µm RMS for higher order aberrations. Lombardo et al, 22 in a study analyzing corneal wavefront for a 6-mm diameter after conventional PRK, reported an increase of 0.08 µm and 0.11 µm for coma and spherical aberration, respectively, for low myopic corrections, and an increase of 0.14 µm and 0.37 µm for coma and spherical aberration, respectively, for high myopic corrections. After conventional LASIK, de Ortueta et al 10 found an increase of 0.10 µm for coma, ϩ0.17 µm for spherical aberration, and 0.20 µm RMS for higher order aberrations for a 6-mm diameter and an increase of 0.07 µm for coma, ϩ0.09 µm for spherical aberration, and 0.02 µm RMS for higher order aberrations after Aberration-Free™ LASIK with a different laser platform.…”

Comparison of higher-order aberration and optical quality after Epi-LASIK and LASIK for myopia

“…The Zernike polynomials were normalized such that over the pupil, the RMS for each Zernike mode was unity [21,22]. The recommended Optical Society of America notation is used, describing individual Zernike terms with a two-index scheme [23,24].…”

Custom selection of aspheric intraocular lenses after wavefront-guided myopic photorefractive keratectomy

“…2,3 Greater change occurs in eyes having larger amounts of correction. 4,5 This increase in spherical aberration is in addition to the inherent positive spherical aberration in the cornea, which is estimated to average 0.28 mm (with a 6.0 mm pupil). 6 As the ever-larger population having refractive surgery ages, growing numbers will require cataract extraction with intraocular lens (IOL) implantation.…”