TY - BOOK AU - Mark Frederic Berge Ananian AU - Ahmed Atef Zaki , AU - Ramy Riad Fikry , AU - Yehia Mahmoud Salah Eldin Mostafa , TI - Effect of modified epithelium off corneal cross linking in a cohort of patients with persistent corneal edema / PY - 2021/// CY - Cairo : PB - Mark Frederic Berge Ananian , KW - Cohort of patients KW - Modified epithelium off corneal cross KW - Persistent corneal edema N1 - Thesis (Ph.D.) - Cairo University - Faculty of Medicine - Department of Ophthalmology; Issued also as CD N2 - The use of riboflavin 0.1% with ultraviolet A (UVA) during corneal collagen crosslinking (CXL) have shown an increase in interfiber corneal attachments, thus decreasing the potential spaces where fluid accumulate during corneal edema.14The early studies that used the standard protocol of CXL showed a transient improvement in central corneal thickness (CCT), visual acuity, pain and cornea clarity.15Patients who had a lower preoperative CCT showed a better improvement in visual acuity and a lower rate of bullae recurrence.16 From this theory,Hafezi et al. decreased the corneal thickness during the CXL procedure by dehydrating the cornea using glycerol with a 70% concentration. After epithelial abrasion and application of isoosmolar riboflavin solution for 30 minutes, if the stroma was thicker than 450æm, glycerol 70% solution was to be instilled every 5 seconds for 2 minutes, and CCT was measured using ultrasound pachymetry. Glycerol 70% solution to be repeated till reaching a CCT of 370-430 æm. CCT was monitored by ultrasound pachymetry every 5 minutes during irradiation and if needed, glycerol 70% solution was re-applied ER -