title: Glaucomatous optic neuropathy evaluation (GONE) project: the effect of monoscopic versus stereoscopic viewing conditions on optic nerve evaluation.
abstract: OBJECTIVE
  To determine whether monoscopic vs stereoscopic viewing impacts evaluation of optic disc photographs for glaucoma diagnosis in an expert population.
  
  
  METHODS
  Prospective observational study.
  
  
  METHODS
  Twenty pairs of high-quality monoscopic and stereoscopic photographs of similar size and magnification (ie, 40 images), were selected to demonstrate a range of optic disc features from a total of 197 eyes of 197 patients with glaucoma and normal subjects recruited from a tertiary clinic. These were presented in randomized order via an interactive platform (http://stereo.gone-project.com/). Participants assessed 9 topographic features and estimated glaucoma likelihood for each photograph. Main outcome measures were intra- and inter-observer agreement.
  
  
  RESULTS
  There was good intra-observer agreement between monoscopic and stereoscopic assessments of glaucoma likelihood (κw = 0.56). There was also good to substantial agreement for peripapillary atrophy (κw = 0.65), cup shape (κw = 0.65), retinal nerve fiber layer loss (κw = 0.69), vertical cup-to-disc ratio (κw = 0.58), and disc shape (κw = 0.57). However, intra-observer agreement was only fair to moderate for disc tilt, cup depth, and disc size (κw = 0.46-0.49). Inter-observer agreement for glaucoma likelihood in monoscopic photographs (κw = 0.61, 95% confidence interval [CI] = 0.55-0.67) was substantial and not lower than in stereoscopic photographs (κw = 0.59, CI = 0.54-0.65). Monoscopic photographs did not lead to lower levels of inter-observer agreement compared to stereoscopic photographs in the assessment of any optic disc characteristics, for example disc size (mono κw = 0.65, stereo κw = 0.52) and cup-to-disc ratio (mono κw = 0.72, stereo κw = 0.62).
  
  
  CONCLUSIONS
  For expert observers in the evaluation of optic disc photographs for glaucoma likelihood, monoscopic optic disc photographs did not appear to represent a significant disadvantage compared to stereoscopic photographs.
authors: Centre for Eye Research Australia, University of Melbourne, Royal Victorian Eye and Ear Hospital, East Melbourne, Victoria, Australia. Electronic address: helen.chan@eyeandear.org.au.
authors: Helen H L
authors: HH
authors: Chan
authors: Centre for Eye Research Australia, University of Melbourne, Royal Victorian Eye and Ear Hospital, East Melbourne, Victoria, Australia.
authors: Dai Ni
authors: DN
authors: Ong
authors: Centre for Eye Research Australia, University of Melbourne, Royal Victorian Eye and Ear Hospital, East Melbourne, Victoria, Australia.
authors: Yu Xiang G
authors: YX
authors: Kong
authors: Centre for Eye Research Australia, University of Melbourne, Royal Victorian Eye and Ear Hospital, East Melbourne, Victoria, Australia; Ophthalmology Department, Mater Misericordiae Hospital, Dublin, Ireland.
authors: Evelyn C
authors: EC
authors: O'Neill
authors: Advanced Eye Center, Postgraduate Institute of Medical Education & Research, Chandigarh, India.
authors: Surinder S
authors: SS
authors: Pandav
authors: Centre for Eye Research Australia, University of Melbourne, Royal Victorian Eye and Ear Hospital, East Melbourne, Victoria, Australia.
authors: Michael A
authors: MA
authors: Coote
authors: Centre for Eye Research Australia, University of Melbourne, Royal Victorian Eye and Ear Hospital, East Melbourne, Victoria, Australia.
authors: Jonathan G
authors: JG
authors: Crowston
mesh_terms: D003867:Depth Perception / Q000502:physiology*; D005901:Glaucoma / Q000175:diagnosis*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D009412:Nerve Fibers / Q000473:pathology*; D015588:Observer Variation; D009898:Optic Disk / Q000473:pathology*; D009901:Optic Nerve Diseases / Q000175:diagnosis*; D010781:Photography; D011446:Prospective Studies; D012165:Retinal Ganglion Cells / Q000473:pathology*; D015349:Vision, Monocular / Q000502:physiology*; D014794:Visual Fields