title: Efficacy and safety of transepithelial collagen cross linking for progressive keratoconus.
abstract: OBJECTIVE
  To evaluate the efficacy and safety of transepithelial (TE) collagen cross-linking (CXL) in patients with progressive keratoconus (KC).
  
  
  METHODS
  This Quasi Experimental Study was conducted at PNS Shifa Naval Hospital, Karachi from June 2015 to June 2016. Sixty eyes of 32 patients who underwent TE CXL for progressive KC from June 2015 to June 2016 were analysed to ascertain efficacy and safety of TE CXL procedure. Statistical analysis of the data was done using SPSS version 17.0.
  
  
  RESULTS
  Twenty eight (87.5%) patients underwent TE CXL bilaterally, while 4 (12.5%) underwent unilateral CXL. Mean change in astigmatism, Maximum simulated Keratometry value (Kmax), Spherical equivalent (SE) and Central Corneal Thickness (CCT) were -0.67±0.35D, 1.28±0.64D, -0.58±0.17D and 0.40±7.58µm respectively, from baseline. Mean gain in lines on Snellen's visual acuity chart was 1.13±0.83 lines. Changes in astigmatism, Kmax and SE were statistically significant (p<0.001), while change in CCT was not statistically significant. The procedure had excellent safety profile, with no major complication till 6 months follow up period.
  
  
  CONCLUSIONS
  TE CXL is a safe and effective procedure with statistically significant reduction in corneal astigmatism, Kmax and SE with reasonable gain in Snellen's visual acuity.
authors.affiliation: Prof. Sameer Shahid Ameen, MCPS, FCPS. Department of Ophthalmology, PNS Shifa Naval Hospital, Karachi, Pakistan.
authors.forename: Sameer Shahid
authors.initials: SS
authors.lastname: Ameen
authors.affiliation: Dr. Mohammad Asim Mehboob, MBBS. Department of Ophthalmology, PNS Shifa Naval Hospital, Karachi, Pakistan.
authors.forename: Mohammad Asim
authors.initials: MA
authors.lastname: Mehboob
authors.affiliation: Dr. Kashif Ali, FCPS. Department of Ophthalmology, PNS Shifa Naval Hospital, Karachi, Pakistan.
authors.forename: Kashif
authors.initials: K
authors.lastname: Ali
keywords: CXL; Collagen Cross linking; Keratoconus