title: Corneal haze and visual outcome after collagen crosslinking for keratoconus: A comparison between total epithelium off and partial epithelial removal methods.
abstract: BACKGROUND
  Keratoconus is an asymmetric, bilateral, progressive noninflammatory ectasia of the cornea that affects approximately 1 in 2000 of the general population. This may cause a significant negative impact on quality of life. Corneal collagen crosslinking (CXL) is one of the recently introduced methods that have been used to decrease the progression of keratoconus, in particular, as well as other corneal-thinning processes.
  
  
  METHODS
  A total of 44 keratoconic eyes of 22 patients were enrolled in this randomized prospective study, after obtaining informed consent. In the first group, the corneal epithelium were totally removed and in the second group, the central 3 mm of epithelium was kept intact and partial removal was performed. After collagen crosslinking in both groups, comprehensive ophthalmologic examination was performed on all patients before and 6 months after the surgery. This article is registered at www.clinicaltrial.gov with registration number NCT01809977.
  
  
  RESULTS
  The difference between the two groups was not statistically significant regarding postoperative corneal haziness, refraction, and visual acuity (P > 0.05). However, comparison of pre- and postoperative parameters within each group revealed that total removal of the cornea has resulted in significant improvement of K-max (P value: 0.01) and Q-value (P value: 0.009); while eyes in partial removal group had better improvement of corrected vision (P value: 0.006). Both methods had significant and similar increase in optical corneal density (P < 0.0001).
  
  
  CONCLUSIONS
  In our study, keeping the central corneal epithelium intact was not beneficial for decreasing corneal haziness, however, this method caused better improvement in corrected vision. Total epithelium off technique resulted in better improvement of K-max and Q-value.
authors.affiliation: Department of Ophthalmology, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Hasan
authors.initials: H
authors.lastname: Razmjoo
authors.affiliation: Department of Ophthalmology, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Behrooz
authors.initials: B
authors.lastname: Rahimi
authors.affiliation: Medical Student Research Committee, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Mona
authors.initials: M
authors.lastname: Kharraji
authors.affiliation: Department of Ophthalmology, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Nima
authors.initials: N
authors.lastname: Koosha
authors.affiliation: Department of Ophthalmology, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Alireza
authors.initials: A
authors.lastname: Peyman
keywords: Corneal haze; UVA; cross-linking; keratoconus; riboflavin