title: Adjusted color probability codes for peripapillary retinal nerve fiber layer thickness in healthy Koreans.
abstract: BACKGROUND
  Though a newly developed spectral domain optical coherence tomography (OCT) is at the center of interests for many ophthalmologic researchers and clinicians, its own characteristics are not fully evaluated yet. The main purpose of this study was to establish the adjusted color probability codes for peripapillary retinal nerve fiber layer (RNFL) thickness in healthy Koreans and to compare them with original color codes provided by spectral domain OCT.
  
  
  METHODS
  Two hundred ninety-five healthy Korean eyes were enrolled and their peripapillary RNFL thickness was measured by Cirrus OCT. For each decade of age, the normal thickness reference was determined on the basis of z-scores and the adjusted color probability codes were established. Then the agreements between adjusted and original color codes were calculated using weighted Kappa (Kw) coefficient.
  
  
  RESULTS
  On the basis of Kw coefficient, the overall agreement between the adjusted and original probability color codes was not excellent (Kw range of 0.500 to 0.806). If the adjusted probability codes were assumed as a standard of comparison, the original color codes showed the false-negative in 11% of eyes and the false-positive in 0.3% of eyes for average RNFL thickness.
  
  
  CONCLUSIONS
  Adjusted color probability codes judged by the Korean normative data showed a discrepancy with original codes. It implies that normal reference and adjusted probability codes for each ethnicity might be needed to determine whether a certain RNFL thickness is within normal range or not.
authors.forename: Samin
authors.initials: S
authors.lastname: Hong
authors.forename: Sang-Myung
authors.initials: SM
authors.lastname: Kim
authors.forename: Kyoungsoo
authors.initials: K
authors.lastname: Park
authors.forename: Jun Mo
authors.initials: JM
authors.lastname: Lee
authors.forename: Chan Yun
authors.initials: CY
authors.lastname: Kim
authors.affiliation: Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-752, Republic of Korea. gjseong@yuhs.ac.
authors.forename: Gong Je
authors.initials: GJ
authors.lastname: Seong
mesh_terms: D000328:Adult; D000368:Aged; D044466:Asian People; D003116:Color; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009412:Nerve Fibers; D009898:Optic Disk / Q000033:anatomy & histology*; D012016:Reference Values; D015203:Reproducibility of Results; D056910:Republic of Korea; D012165:Retinal Ganglion Cells / Q000166:cytology*; D041623:Tomography, Optical Coherence / Q000379:methods / Q000592:standards*; D055815:Young Adult