title: Efficacy of corneal collagen cross-linking for treatment of keratoconus: a meta-analysis of randomized controlled trials.
abstract: OBJECTIVE
  To evaluate the efficacy of corneal collagen cross-linking (CXL) for the treatment of keratoconus.
  
  
  METHODS
  We performed a literature search for randomized controlled trials that assessed the effect of CXL in slowing progression of keratoconus. The primary outcome measures included changes of topographic parameters, visual acuity, and refraction. Efficacy estimates were evaluated by weighted mean difference (WMD) and 95% confidence interval (CI) for absolute changes of the interested outcomes.
  
  
  RESULTS
  Significant decrease in mean keratometry value, maximum keratometry value and minimum keratometry value were demonstrated in the CXL group compared with the control group (WMD = -1.65; 95% CI: -2.51 to -0.80; P < 0.00001; WMD = -2.05; 95% CI: -3.10 to -1.00; P < 0.00001; WMD = -1.94; 95% CI: -2.63 to -1.26; P < 0.00001; respectively). Best spectacle-corrected visual acuity improved significantly in CXL group (WMD = -0.10; 95% CI: -0.15 to -0.05; P < 0.00001), whereas uncorrected visual acuity did not differ statistically. Manifest cylinder error decreased significantly in patients undergoing CXL procedure compared with control patients in sensitivity analysis (WMD = -0.388; 95% CI: -0.757 to -0. 019; P = 0.04). The changes in central corneal thickness and intraocular pressure were not statistically significant.
  
  
  CONCLUSIONS
  CXL may be an effective option in stabilizing keratoconus. Further long-term follow-up studies will be necessary to assess the persistence of CXL.
authors.affiliation: Department of Ophthalmology, Xiangyang Central Hospital, Teaching Hospital of Medical College of Hubei University of arts and science, Xiangyang, Hubei Province, China.
authors.forename: Jingjing
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Operating Theatre, Xiangyang Hospital of Traditional Chinese Medicine, Teaching Hospital of Hubei University of Chinese Medicine, Xiangyang, Hubei Province, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Ji
authors.affiliation: Department of Surgery, Fujian Provincial Tumor Hospital, Teaching Hospital of Fujian Medical University, Fuzhou, China.
authors.forename: Xiaoti
authors.initials: X
authors.lastname: Lin
mesh_terms: D016022:Case-Control Studies; D003094:Collagen / Q000627:therapeutic use*; D003315:Cornea / Q000473:pathology*; D063171:Corneal Pachymetry; D003432:Cross-Linking Reagents / Q000627:therapeutic use*; D006801:Humans; D007429:Intraocular Pressure; D007640:Keratoconus / Q000188:drug therapy* / Q000503:physiopathology; D016032:Randomized Controlled Trials as Topic; D012029:Refraction, Ocular; D016896:Treatment Outcome; D014792:Visual Acuity
chemical_list: D003432:Cross-Linking Reagents; D003094:Collagen