title: Corneal cross-linking with hypo-osmolar riboflavin solution in thin keratoconic corneas.
abstract: OBJECTIVE
  To evaluate the 1-year results of keratoconic eyes with thin corneas that were treated by a hypo-osmolar riboflavin solution and ultraviolet A collagen cross-linking (CXL).
  
  
  METHODS
  Retrospective, nonrandomized study.
  
  
  METHODS
  setting: Department of Ophthalmology, Carl Gustav Carus University Hospital, Dresden, Germany. study population: Thirty-two eyes of 29 patients with progressive keratoconus and a corneal thickness of less than 400 μm (without the epithelium). intervention: Application of a hypo-osmolar riboflavin solution to the cornea after its de-epithelization followed by ultraviolet A collagen cross-linking. main outcome measures: Thirty-two eyes with a follow-up within 1 year were evaluated before and after the procedure. Examinations comprised an evaluation of visual acuity, corneal topography, slit-lamp microscopy, and corneal thickness measurements.
  
  
  RESULTS
  Before surgery, the mean corneal thickness (with the epithelium) was 382.3 ± 41.9 μm, and after the removal of epithelium, the thickness of the cornea was reduced to 337.0 ± 51.9 μm. After the application of the hypo-osmolar riboflavin solution, this value increased to 451.8 ± 46.7 μm. Before surgery, the mean K-value of the apex of the keratoconus was 65.6 ± 11.2 diopters, and 1 year after treatment, this value remained unchanged at 64.9 ± 11.0 diopters (P = .839). Mean best-corrected visual acuity at the time of the treatment was 0.63 ± 0.37 logarithm of the minimal angle of resolution, and 1 year after the treatment, this value was not statistically different (0.59 ± 0.42 logarithm of the minimal angle of resolution; P = .662). At the last follow-up examination, which was 1 year after the procedure, all corneas were transparent, without any scarring lesions in the stroma.
  
  
  CONCLUSIONS
  The results of our study, using hypo-osmolar riboflavin solution in a cross-linking procedure of thin corneas, show a stability of keratoconus one year after cross-linking. Application of the hypo-osmolar riboflavin solution preserved cross-linked corneas from developing stromal scars.
authors.affiliation: Department of Ophthalmology, Carl Gustav Carus University Hospital, Dresden, Germany. Frederik.Raiskup@uniklinikum-dresden.de
authors.forename: Frederik
authors.initials: F
authors.lastname: Raiskup
authors.forename: Eberhard
authors.initials: E
authors.lastname: Spoerl
mesh_terms: D000328:Adult; D003094:Collagen / Q000378:metabolism*; D003319:Corneal Stroma / Q000378:metabolism*; D019781:Corneal Topography; D003432:Cross-Linking Reagents / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D007640:Keratoconus / Q000188:drug therapy* / Q000378:metabolism / Q000503:physiopathology; D008297:Male; D009994:Osmolar Concentration; D017319:Photosensitizing Agents / Q000008:administration & dosage*; D012029:Refraction, Ocular / Q000502:physiology; D012189:Retrospective Studies; D012256:Riboflavin / Q000008:administration & dosage*; D014466:Ultraviolet Rays; D014792:Visual Acuity / Q000502:physiology
chemical_list: D003432:Cross-Linking Reagents; D017319:Photosensitizing Agents; D003094:Collagen; D012256:Riboflavin