title: Retinal nerve fiber layer imaging with spectral-domain optical coherence tomography: a variability and diagnostic performance study.
abstract: OBJECTIVE
  To evaluate and compare the retinal nerve fiber layer (RNFL) measurement variability, diagnostic sensitivity and specificity for glaucoma detection, and strength of the structure-function association obtained with a spectral-domain optical coherence tomography (OCT) device (Cirrus HD-OCT; Carl Zeiss Meditec, Inc., Dublin, CA) and a time-domain OCT device (Stratus OCT; Carl Zeiss Meditec, Inc.).
  
  
  METHODS
  Prospective, cross-sectional study.
  
  
  METHODS
  Ninety-seven normal subjects and 83 glaucoma patients.
  
  
  METHODS
  One eye from each subject was imaged with Cirrus HD-OCT and Stratus OCT. Sixteen and 31 normal eyes were selected randomly to evaluate intravisit repeatability and intervisit reproducibility, respectively. The agreement of RNFL measurements was evaluated with Bland-Altman plots. The diagnostic sensitivity and specificity was examined with the area under the receiver operating characteristic curve (AUC). The association between average RNFL thickness and visual field sensitivity was evaluated with a second-order regression model.
  
  
  METHODS
  Retinal nerve fiber layer measurement variability, AUC, and coefficient of determination (R(2)).
  
  
  RESULTS
  The intravisit repeatability of Cirrus HD-OCT ranged between 5.12 and 15.02 mum, and the intervisit reproducibility ranged between 4.31 and 22.01 mum. The intervisit variabilities of sectoral and average RNFL thicknesses were lower in Cirrus HD-OCT compared with Stratus OCT with significant differences at 1, 3, 4, and 8 to 11 o'clock (P< or =0.021). There were proportional biases of RNFL measurements between the 2 OCT devices. The difference of RNFL thicknesses increased with the means. The average (AUC, 0.962 for Cirrus HD-OCT and 0.956 Stratus OCT), superior (AUC, 0.963 and 0.950, respectively), and inferior (AUC, 0.949 and 0.931, respectively) RNFL thicknesses demonstrated the greatest AUCs in both OCT devices with no significant difference detected between the respective measurements (P> or =0.120). The strength of the structure-function association was comparable between Cirrus HD-OCT (R(2) = 0.580) and Stratus OCT devices (R(2) = 0.623; P = 0.918).
  
  
  CONCLUSIONS
  Although the diagnostic performance and the strength of the structure-function association were comparable between Cirrus HD-OCT and Stratus OCT RNFL measurements, Cirrus HD-OCT demonstrated lower measurement variability compared with Stratus OCT with significant differences at 1, 3, 4, and 8 to 11 o'clock. The poor agreement was likely related to the different inherent characteristics of the 2 OCT systems.
authors.affiliation: Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, People's Republic of China. tlims00@hotmail.com
authors.forename: Christopher Kai-Shun
authors.initials: CK
authors.lastname: Leung
authors.forename: Carol Yim-Lui
authors.initials: CY
authors.lastname: Cheung
authors.forename: Robert N
authors.initials: RN
authors.lastname: Weinreb
authors.forename: Quanliang
authors.initials: Q
authors.lastname: Qiu
authors.forename: Shu
authors.initials: S
authors.lastname: Liu
authors.forename: Haitao
authors.initials: H
authors.lastname: Li
authors.forename: Guihua
authors.initials: G
authors.lastname: Xu
authors.forename: Ning
authors.initials: N
authors.lastname: Fan
authors.forename: Lina
authors.initials: L
authors.lastname: Huang
authors.forename: Chi-Pui
authors.initials: CP
authors.lastname: Pang
authors.forename: Dennis Shun Chiu
authors.initials: DS
authors.lastname: Lam
mesh_terms: D000465:Algorithms; D019540:Area Under Curve; D003430:Cross-Sectional Studies; D005260:Female; D015812:Glaucoma, Angle-Closure / Q000175:diagnosis*; D005902:Glaucoma, Open-Angle / Q000175:diagnosis*; D006801:Humans; D021621:Imaging, Three-Dimensional; D007429:Intraocular Pressure / Q000502:physiology; D008297:Male; D008875:Middle Aged; D009412:Nerve Fibers / Q000473:pathology*; D009898:Optic Disk / Q000473:pathology*; D009901:Optic Nerve Diseases / Q000175:diagnosis*; D011446:Prospective Studies; D015203:Reproducibility of Results; D012165:Retinal Ganglion Cells / Q000473:pathology*; D012680:Sensitivity and Specificity; D013997:Time Factors; D041623:Tomography, Optical Coherence; D014792:Visual Acuity / Q000502:physiology; D014794:Visual Fields / Q000502:physiology