title: Consistency of corneal sublayer thickness measurements using Fourier-domain optical coherence tomography after phacoemulsification.
abstract: OBJECTIVE
  To assess the reliability of corneal epithelial thickness (CET), nonepithelial central corneal thickness (NECCT), and central corneal thickness (CCT) measurements using Cirrus high-definition optical coherence tomography (HD-OCT) in patients who did and did not undergo cataract surgery.
  
  
  METHODS
  Forty patients who underwent uneventful phacoemulsification and 40 healthy participants were recruited to evaluate the intraobserver repeatability and interobserver reproducibility of CET, NECCT, and CCT measurements using Cirrus HD-OCT. To analyze repeatability, one examiner obtained 5 consecutive scans in each participant; for interobserver reproducibility, another examiner randomly obtained another scan. Within-subject standard deviation, coefficient of variation (CV), limits of agreement, and intraclass correlation coefficient (ICC) data were obtained.
  
  
  RESULTS
  For intraobserver repeatability, the intrasession CV (CVw) and ICC values of the CET in the operated and nonoperated groups were 3.7% and 0.80 and 3.8% and 0.73, respectively; for NECCT, 0.7% and 0.98 and 0.8% and 0.97; and for CCT, 0.6% and 0.99 and 0.7% and 0.98. For interobserver reproducibility, the CVw and ICC values for the CET in the operated and nonoperated groups were 2.6% and 0.82 and 2.3% and 0.62, respectively; for NECCT, 0.7% and 0.98 and 0.5% and 0.98; and for CCT, 0.5% and 0.99 and 0.4% and 0.99.
  
  
  CONCLUSIONS
  The corneal sublayer thickness can be measured reliably using Cirrus HD-OCT in patients who underwent cataract surgery and elderly participants; however, the CET consistency is poorer than the NECCT. Corneal epithelial thickness modifications exceeding 4% reflect true thickness changes instead of random error variations using HD-OCT.
authors.affiliation:  IOBA, Universidad de Valladolid, Valladolid - Spain.
authors.forename: Alberto
authors.initials: A
authors.lastname: López-Miguel
authors.affiliation:  IOBA, Universidad de Valladolid, Valladolid - Spain.| Hospital Universitario Rio Hortega, Valladolid - Spain.
authors.forename: María
authors.initials: M
authors.lastname: Calabuig-Goena
authors.affiliation:  Hospital Universitario Rio Hortega, Valladolid - Spain.
authors.forename: Victoria
authors.initials: V
authors.lastname: Marqués-Fernández
authors.affiliation:  Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Valladolid - Spain.
authors.forename: Itziar
authors.initials: I
authors.lastname: Fernández
authors.affiliation:  Vissum Instituto Oftalmologico de Alicante, Alicante - Spain.
authors.forename: Jorge L
authors.initials: JL
authors.lastname: Alió
authors.affiliation:  IOBA, Universidad de Valladolid, Valladolid - Spain.
authors.forename: Miguel J
authors.initials: MJ
authors.lastname: Maldonado
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003315:Cornea / Q000473:pathology*; D063171:Corneal Pachymetry; D005260:Female; D005583:Fourier Analysis; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D018918:Phacoemulsification; D011446:Prospective Studies; D015203:Reproducibility of Results; D041623:Tomography, Optical Coherence / Q000592:standards*