title: Central Corneal Thickness After Cross-linking Using High-Definition Optical Coherence Tomography, Ultrasound, and Dual Scheimpflug Tomography: A Comparative Study Over One Year.
abstract: OBJECTIVE
  To assess central corneal thickness (CCT) and corneal haze in keratoconus eyes following corneal cross-linking (CXL).
  
  
  METHODS
  Prospective noncomparative case series.
  
  
  METHODS
  Forty patients (44 eyes) with keratoconus that had serial evaluation for CCT, following CXL, using high-definition optical coherence tomography (HD-OCT), ultrasound pachymetry (USP), and dual Scheimpflug tomography. CCT was measured at baseline, then at 2 weeks and 1, 3, 6, and 12 months postoperatively.
  
  
  RESULTS
  The mean baseline CCT measurements were 470.02 μm, 469.79 μm, and 466.66 μm using the HD-OCT, the USP, and dual Scheimpflug tomography, respectively (P = .91). Following CXL, the mean CCT measurements by dual Scheimpflug, at all follow-up periods, were lower compared to mean baseline reading (P < .003). The mean CCT measurements by the HD-OCT and USP were similar to baseline readings except for the thicker readings at the 2-week follow-up visit. Overall, the mean CCT obtained by the USP was similar to that obtained by the HD-OCT throughout the 12-month period. However, the mean CCT measurements obtained by dual Scheimpflug tomography were statistically and clinically significantly lower than those obtained by both HD-OCT and USP at all follow-up visits.
  
  
  CONCLUSIONS
  USP and HD-OCT showed better agreement in CCT readings at all visits, and may better estimate the true CCT following CXL as compared to dual Scheimpflug tomography. The lower mean CCT post-CXL as measured by the latter seems to be correlated with the amount of haze that develops after cross-linking.
authors.affiliation: Department of Ophthalmology, American University of Beirut, Beirut, Lebanon.
authors.forename: Rafic
authors.initials: R
authors.lastname: Antonios
authors.affiliation: Department of Ophthalmology, American University of Beirut, Beirut, Lebanon.
authors.forename: Maamoun Abdul
authors.initials: MA
authors.lastname: Fattah
authors.affiliation: Department of Ophthalmology, American University of Beirut, Beirut, Lebanon.
authors.forename: Fadi
authors.initials: F
authors.lastname: Maalouf
authors.affiliation: Department of Ophthalmology, American University of Beirut, Beirut, Lebanon.
authors.forename: Bachir
authors.initials: B
authors.lastname: Abiad
authors.affiliation: Department of Ophthalmology, American University of Beirut, Beirut, Lebanon. Electronic address: sawwad@gmail.com.
authors.forename: Shady T
authors.initials: ST
authors.lastname: Awwad
mesh_terms: D000328:Adult; D003094:Collagen / Q000378:metabolism; D003315:Cornea / Q000000981:diagnostic imaging / Q000473:pathology*; D063171:Corneal Pachymetry; D003319:Corneal Stroma / Q000378:metabolism; D019781:Corneal Topography; D003432:Cross-Linking Reagents; D005260:Female; D006801:Humans; D007640:Keratoconus / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000378:metabolism; D008297:Male; D010778:Photochemotherapy; 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