title: Optical coherence tomography machine learning classifiers for glaucoma detection: a preliminary study.
abstract: OBJECTIVE
  Machine-learning classifiers are trained computerized systems with the ability to detect the relationship between multiple input parameters and a diagnosis. The present study investigated whether the use of machine-learning classifiers improves optical coherence tomography (OCT) glaucoma detection.
  
  
  METHODS
  Forty-seven patients with glaucoma (47 eyes) and 42 healthy subjects (42 eyes) were included in this cross-sectional study. Of the glaucoma patients, 27 had early disease (visual field mean deviation [MD] > or = -6 dB) and 20 had advanced glaucoma (MD < -6 dB). Machine-learning classifiers were trained to discriminate between glaucomatous and healthy eyes using parameters derived from OCT output. The classifiers were trained with all 38 parameters as well as with only 8 parameters that correlated best with the visual field MD. Five classifiers were tested: linear discriminant analysis, support vector machine, recursive partitioning and regression tree, generalized linear model, and generalized additive model. For the last two classifiers, a backward feature selection was used to find the minimal number of parameters that resulted in the best and most simple prediction. The cross-validated receiver operating characteristic (ROC) curve and accuracies were calculated.
  
  
  RESULTS
  The largest area under the ROC curve (AROC) for glaucoma detection was achieved with the support vector machine using eight parameters (0.981). The sensitivity at 80% and 95% specificity was 97.9% and 92.5%, respectively. This classifier also performed best when judged by cross-validated accuracy (0.966). The best classification between early glaucoma and advanced glaucoma was obtained with the generalized additive model using only three parameters (AROC = 0.854).
  
  
  CONCLUSIONS
  Automated machine classifiers of OCT data might be useful for enhancing the utility of this technology for detecting glaucomatous abnormality.
authors.affiliation: UPMC Eye Center, Ophthalmology and Visual Science Research Center, Eye and Ear Institute, Department of Ophthalmology, University of Pittsburgh School of Medicine, PA 15213, USA.
authors.forename: Zvia
authors.initials: Z
authors.lastname: Burgansky-Eliash
authors.forename: Gadi
authors.initials: G
authors.lastname: Wollstein
authors.forename: Tianjiao
authors.initials: T
authors.lastname: Chu
authors.forename: Joseph D
authors.initials: JD
authors.lastname: Ramsey
authors.forename: Clark
authors.initials: C
authors.lastname: Glymour
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Noecker
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ishikawa
authors.forename: Joel S
authors.initials: JS
authors.lastname: Schuman
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D003941:Diagnostic Techniques, Ophthalmological / Q000145:classification*; D005260:Female; D005902:Glaucoma, Open-Angle / Q000145:classification* / Q000175:diagnosis*; D006801:Humans; D007429:Intraocular Pressure; D008297:Male; D008875:Middle Aged; D009412:Nerve Fibers / Q000469:parasitology; D016571:Neural Networks, Computer; D009901:Optic Nerve Diseases / Q000175:diagnosis; D010865:Pilot Projects; D012372:ROC Curve; D015203:Reproducibility of Results; D012165:Retinal Ganglion Cells / Q000469:parasitology; D012680:Sensitivity and Specificity; D041623:Tomography, Optical Coherence / Q000145:classification*