title: Use of progressive glaucomatous optic disk change as the reference standard for evaluation of diagnostic tests in glaucoma.
abstract: OBJECTIVE
  Progressive change in optic disk appearance has been suggested as the best available reference standard for glaucoma diagnosis. We evaluated the accuracy of scanning laser polarimetry (SLP) with variable corneal compensation to discriminate patients with documented progressive optic disk change from healthy subjects.
  
  
  METHODS
  Observational case-control study.
  
  
  METHODS
  Glaucoma patients with documented evidence of progressive optic disk change as assessed by stereoscopic photographs were selected. Healthy control subjects had normal visual fields and normal clinical examination. All subjects underwent imaging with the GDx VCC scanning laser polarimeter. Receiver-operating characteristic (ROC) curves, sensitivities at fixed specificities, and likelihood ratios were calculated.
  
  
  RESULTS
  Sixty-five eyes were healthy control patients. Seventy-one eyes had progressive optic disk change, of which 41 (58%) had abnormal visual field tests closest to the imaging date (perimetric glaucomatous optic neuropathy [GON]), and 30 (42%) eyes had normal visual fields (preperimetric GON). The GDx VCC parameter nerve fiber indicator performed best for discrimination between perimetric GON and normal eyes (AUC = 0.94; sensitivity = 93% for specificity > or =80%) as well as for the discrimination between preperimetric GON and normal eyes (AUC = 0.89; sensitivity = 83% for specificity > or =80%).
  
  
  CONCLUSIONS
  SLP differentiated patients with documented progressive optic disk change from normal subjects and detected abnormalities in patients with confirmed diagnosis of preperimetric GON, suggesting that it may be useful for early glaucoma diagnosis. We suggest that progressive optic disk change should be used in the evaluation of diagnostic accuracy of imaging instruments for glaucoma.
authors.affiliation: Hamilton Glaucoma Center and Department of Ophthalmology, University of California-San Diego, La Jolla, CA 92093-0946, USA. fmedeiros@eyecenter.ucsd.edu
authors.forename: Felipe A
authors.initials: FA
authors.lastname: Medeiros
authors.forename: Linda M
authors.initials: LM
authors.lastname: Zangwill
authors.forename: Christopher
authors.initials: C
authors.lastname: Bowd
authors.forename: Pamela A
authors.initials: PA
authors.lastname: Sample
authors.forename: Robert N
authors.initials: RN
authors.lastname: Weinreb
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D003941:Diagnostic Techniques, Ophthalmological; D018450:Disease Progression; D005901:Glaucoma / Q000175:diagnosis*; D006801:Humans; D007834:Lasers; D016013:Likelihood Functions; D009898:Optic Disk / Q000473:pathology*; D009901:Optic Nerve Diseases / Q000175:diagnosis*; D010781:Photography; D011446:Prospective Studies; D012372:ROC Curve; D012015:Reference Standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014794:Visual Fields