الفهرس 
ANATOMY OF THE CORNEAOnly 14 pages are availabe for public view
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Abstract
In recent years there have been rapid advancements in refractive surgery. Several techniques are available for correction of spherical errors (myopia & hyperopia) as well as astigmatic errors. No single technique has been established as the method of choice, and one wonders whether a combination of some of the known techniques would be advantage.The refractive corneal surgical procedures achieve their effects by modifying the corneal curvature and thickness of previously unoperated healthy eyes. Combinations of corneal incisions, removal or addition of tissue, ablation, or the introduction of optical interfaces are utilized to achieve the intended refractive effects.Each of these producers is indicated for a specific range of refractive errors. Outside which it becomes less effective , and more prone to complications and unpredicatility.Both radial keratotomy and photorefractive keratectomy by the excimer LASER are effective most in the range of simple myopia, while epikeratophakia and keratomileusis are indicated in high errors. That is why epikeratophakia is effective in unilateral aphakia, as well as aphakia in children, and lastly for patients with keratoconus. While phakic intraocular lens and clear lens extration are indicated in high level of myopia.In aphakic eye suffers from optical defects, intraocular lens either primary which had wide acceptance and secondary intraocular lens.