title: Corneal Collagen Cross-Linking for Keratoconus in Pediatric Patients-Long-Term Results.
abstract: OBJECTIVE
  To report the long-term outcome of corneal collagen cross-linking (CXL) for progressive keratoconus in pediatric patients.
  
  
  METHODS
  "Epithelium-off" CXL was performed in pediatric eyes with progressive keratoconus. Spectacle-corrected distance visual acuity (CDVA), retinoscopy, topography, and tomography were documented preoperatively and postoperatively at 3 months, 6 months, 1 year, and annually thereafter.
  
  
  RESULTS
  A total of 377 eyes of 336 pediatric patients aged 8 to 18 years with progressive keratoconus underwent CXL. Of these, 194 eyes had a follow-up beyond 2 years and up to 6.7 years. At last follow-up, there was significant improvement in mean CDVA from 0.33 ± 0.22 to 0.27 ± 0.19 logMAR (P ≤ 0.0001), reduction in mean topographic astigmatism from 7.22 ± 3.55 to 6.13 ± 3.28 D (P = 0.0001), mean flattening of 1.20 ± 3.55 diopters in maximum keratometry (Kmax) (P = 0.0002), and mean corneal thinning of 31.1 ± 36.0 μm (P < 0.0001) after CXL. The mean change in Kmax was most significant in moderately advanced keratoconus (average keratometry 48-53 diopters). Central cones showed more corneal flattening than peripheral cones. Stabilization or flattening of Kmax was seen in 85% of eyes at 2 years and in 76% after 4 years. Stabilization or improvement of CDVA was seen in 80.1% of eyes at 2 years and in 69.1% after 4 years.
  
  
  CONCLUSIONS
  CXL remains effective in stabilizing keratoconus for longer than 2 years in a majority of pediatric eyes. Flattening of Kmax was greater in moderately advanced keratoconus and central cones. Long-term follow-up beyond 4 years, however, revealed that a few eyes showed features suggestive of reversal of the effect of CXL.
authors.affiliation: Department of Cornea and Refractive Surgery, Medical Research Foundation, Sankara Nethralaya, Chennai, India.
authors.forename: Prema
authors.initials: P
authors.lastname: Padmanabhan
authors.forename: Sudhir
authors.initials: S
authors.lastname: Rachapalle Reddi
authors.forename: Rama
authors.initials: R
authors.lastname: Rajagopal
authors.forename: Radhika
authors.initials: R
authors.lastname: Natarajan
authors.forename: Geetha
authors.initials: G
authors.lastname: Iyer
authors.forename: Bhaskar
authors.initials: B
authors.lastname: Srinivasan
authors.forename: Niveditha
authors.initials: N
authors.lastname: Narayanan
authors.forename: Meena
authors.initials: M
authors.lastname: Lakshmipathy
authors.forename: Shweta
authors.initials: S
authors.lastname: Agarwal
mesh_terms: D000293:Adolescent; D002648:Child; D003094:Collagen / Q000378:metabolism*; D063171:Corneal Pachymetry; D003319:Corneal Stroma / Q000378:metabolism*; D019781:Corneal Topography; D003432:Cross-Linking Reagents; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007640:Keratoconus / Q000188:drug therapy* / Q000378:metabolism / Q000503:physiopathology; D008297:Male; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000627:therapeutic use*; D042262:Retinoscopy; D012189:Retrospective Studies; D012256:Riboflavin / Q000627:therapeutic use*; D014466:Ultraviolet Rays; D014792:Visual Acuity / Q000502:physiology
chemical_list: D003432:Cross-Linking Reagents; D017319:Photosensitizing Agents; D003094:Collagen; D012256:Riboflavin