INTRODUCTION

• Keratoconus It is one of the progressive, non-inflammatory, bilateral (yet often asymmetrical) ectatic corneal diseases, manifested by stromal thinning and weakness that results in distorted corneal surface.
• Corneal collagen CXL has emerged as approach to delay or prevent the progression of KC and LASIK ectasia following surgery
• Demarcation lineThis line indicates the transition zone present between cross-linked anterior stroma of the cornea and untreated posterior stroma.
• Recently, OCT has gained interest as an approach for investigation of CXL influences including corneal thickness prior to and following CXL for KC, and demarcation line depth after CXL.



AIM OF THE WORK
The aim of this work was to assess the postoperative corneal alterations following CXL in progressive KC patients using AS-OCT.




Patients
 The study was carried out on 30 eyes of 18 KC patients at private center( El-nour eye centre), Alexandria, Egypt.a prospective intervetional study, non comparative case series ,Age between 15 and 35 years, Keratoconus without significant corneal scarring.