title: Corneal stromal demarcation line after accelerated crosslinking using continuous and pulsed light.
abstract: OBJECTIVE
  To evaluate and compare the depth of corneal stromal demarcation line after accelerated collagen crosslinking (CXL) using continuous and pulsed light ultraviolet-A (UVA) exposure.
  
  
  METHODS
  Department of Ophthalmology, Arcispedale Santa Maria Nuova, Reggio Emilia, Italy.
  
  
  METHODS
  Retrospective case series.
  
  
  METHODS
  Patients with progressive keratoconus were assigned to 1 of 2 treatment protocols using the same irradiation device for accelerated CXL. Patients assigned to Group A received accelerated CXL using continuous UVA light exposure at 30 mW/cm(2) for 4 minutes. Patients assigned to Group B received accelerated CXL using pulsed UVA light with 8 minutes (1 second on/1 second off) of UVA exposure at 30 mW/cm(2) and energy dose of 7.2 J/cm(2). One month after surgery, corneal stromal demarcation line depth was measured by 2 independent observers using anterior segment optical coherence tomography (AS-OCT).
  
  
  RESULTS
  A total of 60 patients were assessed. Corneal stromal demarcation line was easily identified on AS-OCT scans in all eyes by both observers. The mean depth of stromal demarcation line was 149.32 ± 36.03 μm in Group A and 213 ± 47.38 μm in Group B. The difference in stromal demarcation line depth between groups was statistically significant (P < .001).
  
  
  CONCLUSIONS
  Using accelerated CXL, the corneal stromal demarcation line was significantly deeper using pulsed rather than continuous light exposure.
  
  
  BACKGROUND
  No author has financial or proprietary interest in any material or method mentioned.
authors.affiliation: From the Ophthalmology Unit, IRCCS-Arcispedale Santa Maria Nuova, Reggio Emilia, Italy. Electronic address: antonio.moramarco@asmn.re.it.
authors.forename: Antonio
authors.initials: A
authors.lastname: Moramarco
authors.affiliation: From the Ophthalmology Unit, IRCCS-Arcispedale Santa Maria Nuova, Reggio Emilia, Italy.
authors.forename: Alfonso
authors.initials: A
authors.lastname: Iovieno
authors.affiliation: From the Ophthalmology Unit, IRCCS-Arcispedale Santa Maria Nuova, Reggio Emilia, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Sartori
authors.affiliation: From the Ophthalmology Unit, IRCCS-Arcispedale Santa Maria Nuova, Reggio Emilia, Italy.
authors.forename: Luigi
authors.initials: L
authors.lastname: Fontana
mesh_terms: D000293:Adolescent; D000328:Adult; D003094:Collagen / Q000378:metabolism*; D063171:Corneal Pachymetry; D003319:Corneal Stroma / Q000378:metabolism / Q000473:pathology*; D019781:Corneal Topography; D003432:Cross-Linking Reagents; D005260:Female; D006801:Humans; D007640:Keratoconus / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D008297:Male; D018613:Microscopy, Confocal; D017319:Photosensitizing Agents / Q000627:therapeutic use*; D012189:Retrospective 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