title: Comparison of central corneal thickness using optical low-coherence reflectometry and spectral-domain optical coherence tomography.
abstract: OBJECTIVE
  To assess intraobserver and interobserver reliability of central corneal thickness (CCT) measurements using optical low-coherence reflectometry (OLCR) technology and its agreement with spectral-domain optical coherence tomography (SD-OCT).
  
  
  METHODS
  Rio Hortega University Hospital, Valladolid, Spain.
  
  
  METHODS
  Evaluation of diagnostic technology.
  
  
  METHODS
  To analyze OLCR intraobserver repeatability, 1 examiner obtained 4 successive measurements. To study interobserver reproducibility, a different examiner obtained another CCT measurement. To determine agreement with SD-OCT, the first examiner also obtained CCTs. Intraobserver and interobserver within-subject standard deviation (S(w)), coefficient of variation (CV(w)), and limits of agreement (LoA) were obtained for OLCR reliability analysis; for study agreement, data were analyzed using the paired-sample t test and the LoA were calculated.
  
  
  RESULTS
  For OLCR intraobserver repeatability, the S(w) and precision (1.96×S(w)) were 2.33 and 4.56 μm, respectively. The intraobserver CV(w) was 0.42%. For interobserver reproducibility, the S(w) and precision were 11.59 and 22.71 μm, respectively; the CV(w) was 2.10%. The mean difference between observers was -1.35 μm (95% confidence interval [CI], -3.97 to 1.26). The width of the LoA was 45.27 μm. The mean CCT difference between OLCR and SD-OCT was 5.68±11.46 μm (95% CI, 8.29-3.08 μm; P=.0001), and the width of the LoA was 44.93 μm.
  
  
  CONCLUSIONS
  Optical low-coherence reflectometry technology provided reliable intraobserver and interobserver CCT measurements. Although OLCR underestimated the pachymetry by less than 6 μm compared with SD-OCT, its interchangeability fell within the range of interobserver reproducibility. Both noncontact pachymetry measurements seem to be clinically useful and may be used interchangeably with minimum calibration adjustment.
  
  
  BACKGROUND
  No author has a financial or proprietary interest in any material or method mentioned.
authors.affiliation: Institute of Applied Ophthalmobiology, University of Valladolid, Valladolid, Spain.
authors.forename: Alberto
authors.initials: A
authors.lastname: López-Miguel
authors.forename: María Encarnación
authors.initials: ME
authors.lastname: Correa-Pérez
authors.forename: Silvia
authors.initials: S
authors.lastname: Miranda-Anta
authors.forename: Darío
authors.initials: D
authors.lastname: Iglesias-Cortiñas
authors.forename: María Begoña
authors.initials: MB
authors.lastname: Coco-Martín
authors.forename: Miguel J
authors.initials: MJ
authors.lastname: Maldonado
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001699:Biometry / Q000295:instrumentation; D003315:Cornea / Q000033:anatomy & histology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D009929:Organ Size; D015203:Reproducibility of Results; D041623:Tomography, Optical Coherence / Q000295:instrumentation* / Q000379:methods