الفهرس 
Introduction and aim of the workOnly 14 pages are availabe for public view
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Abstract
Keratoconus is a progressive non-inflammatory corneal disease which is bilateral, although asymmetrical in most cases. characterized by paraxial stromal thinning and weakening, resulting in irregular astigmatism, corneal protrusion, and distortion of the anterior corneal surface that is difficult to be treated with galsses and need a hard contact lens to improve the vision but also intolerable. Intrastromal corneal rings were first uesed to treat the myopia but is replaced in this field by LASIK. However, due to its role in reducing the protruion of the cornea by adding tissue to the periphery of the cornea and not by removing tissue from the center of the cornea (as is the case in LASIK), it has been used since 2000 in cases of keratoconus.