title: Combining measurements from three anatomical areas for glaucoma diagnosis using Fourier-domain optical coherence tomography.
abstract: OBJECTIVE
  To improve the diagnostic power for glaucoma by combining measurements of peripapillary nerve fibre layer (NFL), macular ganglion cell complex (GCC) and disc variables obtained with Fourier-domain optical coherence tomography (FD-OCT) into the glaucoma structural diagnostic index (GSDI).
  
  
  METHODS
  In this observational, cross-sectional study of subjects from the Advanced Imaging of Glaucoma Study, GCC and NFL of healthy and perimetrical glaucoma subjects from four major academic referral centres of the Advanced Imaging of Glaucoma Study were mapped with the RTVue FD-OCT. Global loss volume and focal loss volume parameters were defined using NFL and GCC normative reference maps. Optimal weights for NFL, GCC and disc variables were combined using multivariate logistic regression to build the GSDI. Glaucoma severity was classified using the Enhanced Glaucoma Staging System (GSS2). Diagnostic accuracy was assessed by sensitivity, specificity and the area under the receiver operator characteristic curve (AUC).
  
  
  RESULTS
  We analysed 118 normal eyes of 60 subjects, 236 matched eyes of 166 subjects with perimetrical glaucoma, and 105 eyes from a healthy reference group of 61 subjects. The GSDI included composite overall thickness and focal loss volume with weighted NFL and GCC components, as well as the vertical cup-to-disc ratio. The AUC of 0.922 from leave-one-out cross validation was better than the best component variable alone (p=0.047). The partial AUC in the high specificity region was also better (p=0.01), with a sensitivity of 69% at 99% specificity, and a sensitivity of 80.3% at 95% specificity. For GSS2 stages 3-5 the sensitivity was 98% at 99% specificity, and 100% at 95% specificity.
  
  
  CONCLUSIONS
  Combining structural measurements of GCC, NFL and disc variables from FD-OCT created a GSDI that improved the accuracy for glaucoma diagnosis.
  
  
  BACKGROUND
  NCT01314326.
authors: Department of Ophthalmology, UPMC Eye Center, Ophthalmology and Visual Science Research Center, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.
authors: Nils A
authors: NA
authors: Loewen
authors: Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, USA.
authors: Xinbo
authors: X
authors: Zhang
authors: Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, USA.
authors: Ou
authors: O
authors: Tan
authors: Doheny Eye Institute, University of Southern California, Los Angeles, California, USA Doheny Eye Institute, University of California, Los Angeles, California, USA.
authors: Brian A
authors: BA
authors: Francis
authors: Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Palm Beach Gardens, Florida, USA.
authors: David S
authors: DS
authors: Greenfield
authors: Department of Ophthalmology, UPMC Eye Center, Ophthalmology and Visual Science Research Center, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.
authors: Joel S
authors: JS
authors: Schuman
authors: USC Eye Institute and the Department of Ophthalmology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA.
authors: Rohit
authors: R
authors: Varma
authors: Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, USA.
authors: David
authors: D
authors: Huang
mesh_terms: D000368:Aged; D019540:Area Under Curve; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D005260:Female; D005583:Fourier Analysis; D005901:Glaucoma / Q000175:diagnosis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009412:Nerve Fibers / Q000473:pathology*; D012165:Retinal Ganglion Cells / Q000473:pathology*; D012680:Sensitivity and Specificity; D041623:Tomography, Optical Coherence / Q000379:methods*; D058609:Visual Field Tests
keywords: Diagnostic tests/Investigation; Glaucoma; Imaging