title: Regression Analysis of Optical Coherence Tomography Disc Variables for Glaucoma Diagnosis.
abstract: To report diagnostic accuracy of optical coherence tomography (OCT) disc variables using both time-domain (TD) and Fourier-domain (FD) OCT, and to improve the use of OCT disc variable measurements for glaucoma diagnosis through regression analyses that adjust for optic disc size and axial length-based magnification error.
  
  
  
  Observational, cross-sectional.
  
  
  
  In total, 180 normal eyes of 112 participants and 180 eyes of 138 participants with perimetric glaucoma from the Advanced Imaging for Glaucoma Study.
  
  
  
  Diagnostic variables evaluated from TD-OCT and FD-OCT were: disc area, rim area, rim volume, optic nerve head volume, vertical cup-to-disc ratio (CDR), and horizontal CDR. These were compared with overall retinal nerve fiber layer thickness and ganglion cell complex. Regression analyses were performed that corrected for optic disc size and axial length. Area-under-receiver-operating curves (AUROC) were used to assess diagnostic accuracy before and after the adjustments. An index based on multiple logistic regression that combined optic disc variables with axial length was also explored with the aim of improving diagnostic accuracy of disc variables.
  
  
  
  Comparison of diagnostic accuracy of disc variables, as measured by AUROC.
  
  
  
  The unadjusted disc variables with the highest diagnostic accuracies were: rim volume for TD-OCT (AUROC=0.864) and vertical CDR (AUROC=0.874) for FD-OCT. Magnification correction significantly worsened diagnostic accuracy for rim variables, and while optic disc size adjustments partially restored diagnostic accuracy, the adjusted AUROCs were still lower. Axial length adjustments to disc variables in the form of multiple logistic regression indices led to a slight but insignificant improvement in diagnostic accuracy.
  
  
  
  Our various regression approaches were not able to significantly improve disc-based OCT glaucoma diagnosis. However, disc rim area and vertical CDR had very high diagnostic accuracy, and these disc variables can serve to complement additional OCT measurements for diagnosis of glaucoma.
authors.affiliation: *USC Eye Institute, Department of Ophthalmology, Keck School of Medicine of University of Southern California, Los Angeles, CA ‡Doheny Eye Institute, University of California, Los Angeles †Casey Eye Institute, Oregon Health & Science University, Portland, OR §Bascom Palmer Eye Institute, University of Miami, Miami, FL ∥Eye and Ear Institute, University of Pittsburgh Medical Center, Pittsburgh, PA.
authors.forename: Grace M
authors.initials: GM
authors.lastname: Richter
authors.forename: Xinbo
authors.initials: X
authors.lastname: Zhang
authors.forename: Ou
authors.initials: O
authors.lastname: Tan
authors.forename: Brian A
authors.initials: BA
authors.lastname: Francis
authors.forename: Vikas
authors.initials: V
authors.lastname: Chopra
authors.forename: David S
authors.initials: DS
authors.lastname: Greenfield
authors.forename: Rohit
authors.initials: R
authors.lastname: Varma
authors.forename: Joel S
authors.initials: JS
authors.lastname: Schuman
authors.forename: David
authors.initials: D
authors.lastname: Huang
mesh_terms: D000328:Adult; D000368:Aged; D019540:Area Under Curve; D058452:Axial Length, Eye / Q000033:anatomy & histology; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D005260:Female; D005901:Glaucoma / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology; D006801:Humans; D007429:Intraocular Pressure; D008297:Male; D008875:Middle Aged; D009898:Optic Disk / Q000473:pathology; D012372:ROC Curve; D012044:Regression Analysis; D012160:Retina / Q000000981:diagnostic imaging* / Q000473:pathology; D012165:Retinal Ganglion Cells / Q000473:pathology; D012680:Sensitivity and Specificity; D041623:Tomography, Optical Coherence / Q000379:methods*; D058609:Visual Field Tests; D014794:Visual Fields