title: Baseline OCT measurements in the idiopathic intracranial hypertension treatment trial, part I: quality control, comparisons, and variability.
abstract: OBJECTIVE
  Optical coherence tomography (OCT) has been used to investigate papilledema in single-site, mostly retrospective studies. We investigated whether spectral-domain OCT (SD-OCT), which provides thickness and volume measurements of the optic nerve head and retina, could reliably demonstrate structural changes due to papilledema in a prospective multisite clinical trial setting.
  
  
  METHODS
  At entry, 126 subjects in the Idiopathic Intracranial Hypertension Treatment Trial (IIHTT) with mild visual field loss had optic disc and macular scans, using the Cirrus SD-OCT. Images were analyzed by using the proprietary commercial and custom 3D-segmentation algorithms to calculate retinal nerve fiber layer (RNFL), total retinal thickness (TRT), optic nerve head volume (ONHV), and retinal ganglion cell layer (GCL) thickness. We evaluated variability, with interocular comparison and correlation between results for both methods.
  
  
  RESULTS
  The average RNFL thickness > 95% of normal controls in 90% of eyes and the RNFL, TRT, ONH height, and ONHV showed strong (r > 0.8) correlations for interocular comparisons. Variability for repeated testing of OCT parameters was low for both methods and intraclass correlations > 0.9 except for the proprietary GCL thickness. The proprietary algorithm-derived RNFL, TRT, and GCL thickness measurements had failure rates of 10%, 16%, and 20% for all eyes respectively, which were uncommon with 3D-segmentation-derived measurements. Only 7% of eyes had GCL thinning that was less than fifth percentile of normal age-matched control eyes by both methods.
  
  
  CONCLUSIONS
  Spectral-domain OCT provides reliable continuous variables and quantified assessment of structural alterations due to papilledema. (ClinicalTrials.gov number, NCT01003639.).
authors.forename: Peggy
authors.initials: P
authors.lastname: Auinger
authors.forename: Mary
authors.initials: M
authors.lastname: Durbin
authors.forename: Steven
authors.initials: S
authors.lastname: Feldon
authors.forename: Mona
authors.initials: M
authors.lastname: Garvin
authors.forename: Randy
authors.initials: R
authors.lastname: Kardon
authors.forename: John
authors.initials: J
authors.lastname: Keltner
authors.forename: Mark
authors.initials: M
authors.lastname: Kupersmith
authors.forename: Patrick
authors.initials: P
authors.lastname: Sibony
authors.forename: Kim
authors.initials: K
authors.lastname: Plumb
authors.forename: Jui-Kai
authors.initials: JK
authors.lastname: Wang
authors.forename: John S
authors.initials: JS
authors.lastname: Werner
mesh_terms: D000328:Adult; D000465:Algorithms; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D019586:Intracranial Hypertension / Q000150:complications* / Q000188:drug therapy; D008266:Macula Lutea / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009412:Nerve Fibers / Q000473:pathology; D009898:Optic Disk / Q000473:pathology; D010211:Papilledema / Q000175:diagnosis* / Q000473:pathology; D011446:Prospective Studies; D011786:Quality Control; D015203:Reproducibility of Results; D012165:Retinal Ganglion Cells / Q000473:pathology; D041623:Tomography, Optical Coherence / Q000592:standards; D055815:Young Adult
keywords: OCT; intracranial hypertension; optical coherence tomography; papilledema