الفهرس 
Aim of the workOnly 14 pages are availabe for public view
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Abstract
The eye is an optical system that has several optical elements that focus light rays representing images onto the retina. Imperfections in the components and materials in the eye may cause light rays to deviate from the desired path. These deviations, referred to as optical aberrations, result in blurred images and decreased visual performance. Historically, refractive errors of the human eye were corrected by glasses or contact lenses or more recently excimer laser surgery. However, such corrections were limited to the compensation of myopia, hyperopia, or regular astigmatism known as lower order aberrations. With no regard to the fact that the optical system of the human eye as a genuine optical system generates more complex distortions to the retinal images, the so-called higher order aberrations. Also, higher order aberrations have been observed to increase after both conventional PRK and standard LASIK and may be responsible for poor image quality, night vision problems and low contrast visual acuity especially in dim light conditions experienced by many keratorefractive surgery patients despite low or no residual sphero-cylinderical errors. New advances in wavefront technology with accompanying advances in laser platforms have allowed us not only to quantify these HOAs but try to correct them as well. These advances helped us to determine the origin of these HOAs and the correlation between them.