title: Comparison of the Conventional Dresden Protocol and Accelerated Protocol With Higher Ultraviolet Intensity in Corneal Collagen Cross-Linking for Keratoconus.
abstract: OBJECTIVE
  To compare the accelerated corneal cross-linking (CXL) protocol and the conventional Dresden protocol in patients with keratoconus in terms of visual acuity, keratometric values, and topographic parameters.
  
  
  METHODS
  Twenty-eight eyes of 25 patients with primary keratoconus were divided into 2 groups; 15 eyes in group 1 received CXL under the standard Dresden protocol (3 mW/cm for 30 min, dose 5.4 J/cm) and 13 eyes in group 2 were treated with the accelerated protocol (30 mW/cm for 3 min 40 s, dose 6.6 J/cm). Visual acuity, refractive error, keratometry values obtained by both Pentacam and Auto Kerato-Refractometer, corneal thickness, and topometric indexes were compared 6 months postoperatively.
  
  
  RESULTS
  The visual acuity improved significantly from 0.17 ± 0.16 to 0.08 ± 0.09 logarithm of the minimum angle of resolution in group 1 (P = 0.009). The cylindrical refractive error improved in both groups (P = 0.05 in group 1 and P = 0.011 in group 2), and the spherical equivalent increased in group 1 (P = 0.021). In group 1, the maximum keratometry value decreased by 0.55 ± 0.89 diopters (P = 0.03), and the mean keratometry value decreased by 0.44 ± 0.63 diopters (P = 0.017), whereas the changes in visual acuity, spherical and spherical equivalent refractive errors, and keratometric values in group 2 were not statistically significant. The corneal thickness at the apex decreased significantly in group 1 (P = 0.001), but the change was not significant in group 2.
  
  
  CONCLUSIONS
  Despite a higher UV dose (6.6 J/cm), accelerated CXL with higher UV intensity and reduced irradiation time showed a smaller topographic flattening effect than did the conventional Dresden protocol in primary keratoconus with documented progression.
authors.affiliation: *Department of Ophthalmology, Institute of Vision Research, Yonsei University College of Medicine, Seoul, South Korea; and †Department of Ophthalmology, Cornea Dystrophy Research Institute, Yonsei University College of Medicine, Seoul, South Korea.
authors.forename: Moonjung
authors.initials: M
authors.lastname: Choi
authors.forename: Jiwon
authors.initials: J
authors.lastname: Kim
authors.forename: Eung Kweon
authors.initials: EK
authors.lastname: Kim
authors.forename: Kyoung Yul
authors.initials: KY
authors.lastname: Seo
authors.forename: Tae-Im
authors.initials: TI
authors.lastname: Kim
mesh_terms: D000328:Adult; D003094:Collagen / Q000378:metabolism; D003315:Cornea / Q000187:drug effects / Q000378:metabolism; D003319:Corneal Stroma / Q000378:metabolism; D019781:Corneal Topography; D003432:Cross-Linking Reagents / Q000627:therapeutic use*; 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*; D011446:Prospective Studies; D012029:Refraction, Ocular; D012256:Riboflavin / Q000627:therapeutic use*; D014466:Ultraviolet Rays; D014792:Visual Acuity; D055815:Young Adult
chemical_list: D003432:Cross-Linking Reagents; D017319:Photosensitizing Agents; D003094:Collagen; D012256:Riboflavin