الفهرس 
Introduction
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Abstract
Laser in situ keratomileusis (LASIK) is currently the most popular refractive procedure. Most cases are eventless and provide excellent refractive results. Nevertheless, anecdotal reports have been published showing that LASIK’s transient elevation of intraocular pressure (IOP) during suction ring application can have potential deleterious effects on posterior segment in myopic eyes, and only careful and large prospective studies can determine whether the procedure exacerbates myopic abnormalities. A dilated fundus examination is very important before LASIK and in every patient whose VA after LASIK is not as good as expected to avoid delayed referral to a vitreoretinal specialist if necessary.
The aim of this work is to assess the influence of transient elevation in intraocular pressure (IOP) during suction in laser assisted in situ Keratomileusis (LASIK) on viteroretinal changes assessed by ultrasonography, optical coherence tomography (OCT) and Humphery visual field testing.
Optical coherence tomography (OCT) is a rapid noncontact method that allows in vivo imaging of the retina, optic nerve head and retinal nerve fibre layer (RNFL). Since its introduction in Ophthalmology approximately a decade ago, the use of this technology has disseminated into the clinical practice. OCT has proven to be a useful ancillary tool for assessing retinal diseases because of its capability to provide crosssectional images of the retina, and also to perform quantitative analysis of retinal morphology. In glaucoma, the OCT represents one of the methods capable of documenting and analysing optic disc and RNFL morphology in attempt to diagnose and monitor glaucomatous optic neuropathy.
The study was conducted on 61 eyes of 31patients with moderate myopia was assessed one week before and one week after LASIK using optical coherence tomography.
In this study, it was found that LASIK does not affect the retinal nerve fiber layer and ganglion cell thickness.
WE found that older age, longer eyes and higher spherical equivilant were associated with increased incidence of PVD.
Regarding the visual field, we noticed that visual field modifications in our study were diffuse defects rather than localized.
This may be attributed to decreased contrast sensitivity in the mid peripheral visual field due to optical factors related to corneal aberration rather than optic nerve or retinal nerve fiber layer damage.
Further studies with larger number of cases and longer follow-up periods are needed to evaluate the long-term effects of LASIK on posterior segment.
So, the surgery of Laser in situ keratomileusis is a safe and effective method for the correction of refractive errors.