title: Optimizing Corneal Cross-Linking in the Treatment of Keratoconus: A Comparison of Outcomes After Standard- and High-Intensity Protocols.
abstract: OBJECTIVE
  To evaluate and compare the safety and efficacy of accelerated (AXL) and standard corneal cross-linking (CXL) protocols in patients with progressive keratoconus.
  
  
  METHODS
  Progressive keratoconus patients (14-40 years) received either standard-intensity CXL or high-intensity CXL (AXL). Corneas were exposed to ultraviolet-A 365 nm light for 30 minutes at an irradiance of 3.0 mW/cm in the standard CXL group and to ultraviolet-A 365 nm light for 10 minutes at 9.0 mW/cm in the AXL group. Changes in uncorrected visual acuity, best spectacle-corrected visual acuity, refractive astigmatism, Kmax, and Kmean were used to determine treatment efficacy. Safety was determined by the incidence of adverse events and occurrence of loss of 2 or more lines of best spectacle-corrected visual acuity. Outcomes for CXL versus AXL were compared to determine differences in safety and efficacy between treatment groups.
  
  
  RESULTS
  Thirty-six eyes of 34 patients (mean age, 27.9 ± 7.6 years) underwent AXL; 66 eyes of 53 patients (mean age, 30.0 ± 8.0 years) underwent standard-intensity CXL. There was no significant difference in any outcome measures between the groups. For AXL, there seemed to be more corneal flattening, with a statistically significant reduction in Kmean at 6 and 12 months postoperatively, when compared preoperatively (P < 0.01). There were no adverse events or complications in any patients.
  
  
  CONCLUSIONS
  There was more corneal flattening in AXL patients 6 to 12 months postoperatively, suggesting that AXL may be a promising alternative to CXL in stabilizing corneal ectasia.
authors.affiliation: *Wellington Eye Clinic, Dublin, Ireland; and †IROC Science to Innovation AG, Zürich, Switzerland.
authors.forename: Arthur B
authors.initials: AB
authors.lastname: Cummings
authors.forename: Rebecca
authors.initials: R
authors.lastname: McQuaid
authors.forename: Stephanie
authors.initials: S
authors.lastname: Naughton
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Brennan
authors.forename: Michael
authors.initials: M
authors.lastname: Mrochen
mesh_terms: D000293:Adolescent; D000328:Adult; D003094:Collagen / Q000378:metabolism*; D063171:Corneal Pachymetry; D003319:Corneal Stroma / Q000378:metabolism*; D003432:Cross-Linking Reagents; D005260:Female; D006801:Humans; D007640:Keratoconus / Q000188:drug therapy* / Q000378:metabolism / Q000503:physiopathology; D008297:Male; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000627:therapeutic use*; D012029:Refraction, Ocular / Q000502:physiology; D012256:Riboflavin / Q000627:therapeutic use*; D014466:Ultraviolet Rays; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult
chemical_list: D003432:Cross-Linking Reagents; D017319:Photosensitizing Agents; D003094:Collagen; D012256:Riboflavin