title: Likelihood ratios for glaucoma diagnosis using spectral-domain optical coherence tomography.
abstract: OBJECTIVE
  To present a methodology for calculating likelihood ratios for glaucoma diagnosis for continuous retinal nerve fiber layer (RNFL) thickness measurements from spectral-domain optical coherence tomography (spectral-domain OCT).
  
  
  METHODS
  Observational cohort study.
  
  
  METHODS
  A total of 262 eyes of 187 patients with glaucoma and 190 eyes of 100 control subjects were included in the study. Subjects were recruited from the Diagnostic Innovations Glaucoma Study. Eyes with preperimetric and perimetric glaucomatous damage were included in the glaucoma group. The control group was composed of healthy eyes with normal visual fields from subjects recruited from the general population. All eyes underwent RNFL imaging with Spectralis spectral-domain OCT. Likelihood ratios for glaucoma diagnosis were estimated for specific global RNFL thickness measurements using a methodology based on estimating the tangents to the receiver operating characteristic (ROC) curve.
  
  
  RESULTS
  Likelihood ratios could be determined for continuous values of average RNFL thickness. Average RNFL thickness values lower than 86 μm were associated with positive likelihood ratios (ie, likelihood ratios greater than 1), whereas RNFL thickness values higher than 86 μm were associated with negative likelihood ratios (ie, likelihood ratios smaller than 1). A modified Fagan nomogram was provided to assist calculation of posttest probability of disease from the calculated likelihood ratios and pretest probability of disease.
  
  
  CONCLUSIONS
  The methodology allowed calculation of likelihood ratios for specific RNFL thickness values. By avoiding arbitrary categorization of test results, it potentially allows for an improved integration of test results into diagnostic clinical decision making.
authors: Hamilton Glaucoma Center, Department of Ophthalmology, University of California San Diego, La Jolla, California.
authors: Renato
authors: R
authors: Lisboa
authors: Kaweh
authors: K
authors: Mansouri
authors: Linda M
authors: LM
authors: Zangwill
authors: Robert N
authors: RN
authors: Weinreb
authors: Felipe A
authors: FA
authors: Medeiros
mesh_terms: D000368:Aged; D005260:Female; D005901:Glaucoma / Q000175:diagnosis*; D006068:Gonioscopy; D006801:Humans; D007429:Intraocular Pressure; D016013:Likelihood Functions; D008297:Male; D008875:Middle Aged; D009412:Nerve Fibers / Q000473:pathology*; D009901:Optic Nerve Diseases / Q000175:diagnosis*; D012372:ROC Curve; D012165:Retinal Ganglion Cells / Q000473:pathology*; D041623:Tomography, Optical Coherence / Q000706:statistics & numerical data*; D014792:Visual Acuity; D014794:Visual Fields
references: Ophthalmology. 2008 Aug;115(8):1340-6
references: 18207246
references: Invest Ophthalmol Vis Sci. 2002 Nov;43(11):3444-54
references: 12407155
references: Invest Ophthalmol Vis Sci. 2006 Jun;47(6):2520-7
references: 16723465
references: Am J Ophthalmol. 2011 Jan;151(1):85-92.e1
references: 20970108
references: Am J Epidemiol. 1998 Dec 1;148(11):1127-32
references: 9850136
references: Invest Ophthalmol Vis Sci. 2013 May 13;54(5):3417-25
references: 23532529
references: Opt Express. 2009 Mar 2;17(5):4004-18
references: 19259242
references: Arch Ophthalmol. 2009 Sep;127(9):1136-45
references: 19752422
references: Br J Ophthalmol. 2011 Apr;95(4):509-13
references: 20657017
references: Arch Ophthalmol. 2004 Jun;122(6):827-37
references: 15197057
references: Ophthalmology. 2009 Jul;116(7):1257-63, 1263.e1-2
references: 19464061
references: Ophthalmology. 2012 Nov;119(11):2261-9
references: 22883689
references: Arch Ophthalmol. 2009 Dec;127(12):1603-9
references: 20008715
references: Am J Emerg Med. 1997 Nov;15(7):694-9
references: 9375556
references: Biometrics. 2004 Jun;60(2):528-35
references: 15180681
references: Eye (Lond). 2011 Jan;25(1):57-65
references: 20930859
references: Invest Ophthalmol Vis Sci. 2010 Aug;51(8):4104-9
references: 20335619
references: Stat Med. 2004 Jun 15;23(11):1701-13
references: 15160403
references: Ophthalmology. 2009 Dec;116(12):2294-9
references: 19800694
references: JAMA. 1994 Mar 2;271(9):703-7
references: 8309035
references: Fam Med. 1999 Jun;31(6):432-7
references: 10367208
references: Am J Epidemiol. 2008 Jul 1;168(1):89-97
references: 18477651
references: Biostatistics. 2002 Sep;3(3):421-32
references: 12933607
references: Ophthalmology. 2010 Feb;117(2):267-74
references: 19969364
references: Am J Ophthalmol. 2012 May;153(5):815-826.e2
references: 22265147
references: Br J Ophthalmol. 2007 Mar;91(3):273-4
references: 17322462
references: Invest Ophthalmol Vis Sci. 2011 Mar 10;52(3):1290-6
references: 20811060
references: Pharm Stat. 2009 Jan-Mar;8(1):50-61
references: 18389492
references: Ophthalmology. 2010 Mar;117(3):453-61
references: 20031231
references: Ophthalmology. 2010 Sep;117(9):1692-9, 1699.e1
references: 20493529
references: Am J Ophthalmol. 2005 Jun;139(6):1010-8
references: 15953430
references: Invest Ophthalmol Vis Sci. 2007 Jan;48(1):214-22
references: 17197535
references: Ophthalmology. 2011 Jul;118(7):1334-9
references: 21377735
references: N Engl J Med. 1975 Jul 31;293(5):257
references: 1143310
references: Stat Med. 2006 Jan 15;25(1):127-41
references: 16217841
references: Arch Pathol Lab Med. 1986 Aug;110(8):689-93
references: 3755325
references: Biostatistics. 2011 Jan;12(1):87-101
references: 20639522