title: Corneal Stromal Demarcation Line Depth Following Standard and a Modified High Intensity Corneal Cross-linking Protocol.
abstract: OBJECTIVE
  To compare the corneal stromal demarcation line depth using anterior segment optical coherence tomography (AS-OCT) after corneal cross-linking (CXL) using two different treatment protocols: the standard Dresden protocol (30 minutes with 3 mW/cm(2)) and a modified high intensity protocol (7 minutes with 18 mW/cm(2)), corresponding to a total surface dose of 5.4 and 7.5 J/cm(2), respectively.
  
  
  METHODS
  This prospective, comparative, interventional case series included 29 keratoconic patients (32 eyes). All patients underwent CXL using the same high intensity ultraviolet-A (UV-A) irradiation device (CCL-365; Peschke Meditrade GmbH, Huenenberg, Switzerland). Sixteen eyes were treated for 30 minutes with 3 mW/cm(2) according to the standard Dresden protocol, whereas 16 eyes were treated with a novel modified high intensity CXL protocol for 7 minutes with 18 mW/cm(2) of UV-A irradiation intensity. One month postoperatively, corneal stromal demarcation line depth was measured by two independent observers using AS-OCT.
  
  
  RESULTS
  There was no significant difference in corneal stromal demarcation line depth between observer measurements for both groups (P = .645, Dresden protocol group; P = .715, high intensity group). Mean corneal stromal demarcation line depth was 341.81 ± 47.02 µm for the Dresden protocol group and 313.37 ± 48.85 µm for the high intensity protocol group. There was no statistically significant difference (P = .104) in the corneal stromal demarcation line depth between the two groups. Mean endothelial cell density did not change significantly in either group (P = .090, Dresden protocol group; P = .103, high intensity group). No intraoperative or postoperative complications were noted.
  
  
  CONCLUSIONS
  Corneal stromal demarcation line depth using UV-A irradiance with 3 mW/cm(2) for 30 minutes and 18 mW/cm(2) for 7 minutes was similar. It seems that the current modified accelerated CXL protocol provided the same treatment depth as the standard Dresden protocol.
authors.forename: George D
authors.initials: GD
authors.lastname: Kymionis
authors.forename: Konstantinos I
authors.initials: KI
authors.lastname: Tsoulnaras
authors.forename: Dimitrios A
authors.initials: DA
authors.lastname: Liakopoulos
authors.forename: Christina A
authors.initials: CA
authors.lastname: Skatharoudi
authors.forename: Michael A
authors.initials: MA
authors.lastname: Grentzelos
authors.forename: Nikolaos G
authors.initials: NG
authors.lastname: Tsakalis
mesh_terms: D000328:Adult; D059925:Anatomic Landmarks; D003094:Collagen / Q000378:metabolism; D003319:Corneal Stroma / Q000187:drug effects / Q000378:metabolism / Q000473:pathology*; D019781:Corneal Topography; D003432:Cross-Linking Reagents; D005260:Female; D006801:Humans; D007640:Keratoconus / Q000175:diagnosis / Q000188:drug therapy* / Q000378:metabolism; D008297:Male; D015588:Observer Variation; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000627:therapeutic use*; D011446:Prospective Studies; D012256:Riboflavin / Q000627:therapeutic use; D041623:Tomography, Optical Coherence; D014466:Ultraviolet Rays; D055815:Young Adult
chemical_list: D003432:Cross-Linking Reagents; D017319:Photosensitizing Agents; D003094:Collagen; D012256:Riboflavin