title: Intraoperative pachymetry using spectral-domain optical coherence tomography during accelerated corneal collagen crosslinking.
abstract: OBJECTIVE
  To evaluate the role of spectral-domain optical coherence tomography (SDOCT) to measure corneal thickness during accelerated corneal crosslinking (CXL).
  
  
  METHODS
  Intraoperative pachymetry was performed using SDOCT and ultrasound pachymetry (USP) in 6 eyes of 6 patients with keratoconus. Pachymetry readings were obtained at baseline, after epithelium removal and after 30 minutes of riboflavin instillation. SDOCT measurements of eyes with and without lid speculum during riboflavin instillation were compared.
  
  
  RESULTS
  There was no statistically significant difference in central corneal thickness (CCT) measurements between SDOCT and USP (P > 0.05 for all). A significant decrease in both CCT (P = 0.031) and the thinnest corneal thickness (TCT) (P = 0.031) was observed during CXL. There was a greater reduction in CCT (38 ± 6%) with the use of lid speculum as compared to the no-speculum eyes (18 ± 9%) (P = 0.100). TCT was also reduced by a greater extent with the use of lid speculum (40 ± 5% versus 26 ± 7%; P = 0.100).
  
  
  CONCLUSIONS
  SDOCT can be successfully used to measure intraoperative corneal pachymetry during corneal CXL. SDOCT measurements demonstrated corneal thinning intraoperatively during CXL, which was further accentuated by the use of a lid speculum during the procedure.
authors.affiliation: Hong Kong Eye Hospital, Hong Kong.
authors.forename: Vanissa W S
authors.initials: VW
authors.lastname: Chow
authors.forename: Sayantan
authors.initials: S
authors.lastname: Biswas
authors.forename: Marco
authors.initials: M
authors.lastname: Yu
authors.forename: Victoria W Y
authors.initials: VW
authors.lastname: Wong
authors.forename: Vishal
authors.initials: V
authors.lastname: Jhanji
mesh_terms: D003094:Collagen / Q000378:metabolism*; D003315:Cornea / Q000000981:diagnostic imaging / Q000473:pathology* / Q000528:radiation effects / Q000601:surgery*; D063171:Corneal Pachymetry; D003432:Cross-Linking Reagents / Q000494:pharmacology*; D006801:Humans; D007430:Intraoperative Care; D013525:Surgical Instruments; D041623:Tomography, Optical Coherence; D014463:Ultrasonography; D014466:Ultraviolet Rays
chemical_list: D003432:Cross-Linking Reagents; D003094:Collagen