title: Comparison of optic nerve head assessment with a digital stereoscopic camera (discam), scanning laser ophthalmoscopy, and stereophotography.
abstract: OBJECTIVE
  To compare computer-assisted planimetry using the Discam system (Marcher Enterprises Ltd., Hereford, UK), confocal scanning laser ophthalmoscopy (CSLO), and stereoscopic disc photography with respect to optic nerve head (ONH) measurements and glaucoma status.
  
  
  METHODS
  Comparative, observational case series and interobserver variability study.
  
  
  METHODS
  Three hundred eighty-six eyes of 233 consecutive subjects were imaged with the Discam, and a subset underwent ONH evaluation with CSLO (n = 297), stereoscopic photography (n = 233), or both. Subjects were classified into normal, glaucoma suspect, and glaucoma groups based on clinical findings of slit-lamp disc examination and visual field testing. Agreement of cup-to-disc ratio measurements among the three technologies was assessed by the intraclass correlation coefficient (ICC) and areas under the receiver operator characteristic (AROC) curves.
  
  
  METHODS
  Cup-to-disc ratio as measured by Discam, CSLO, and stereography.
  
  
  RESULTS
  Intraclass correlation coefficients calculated using the two-way random effects model for comparing Discam, CSLO, and stereography among cup-to-disc area ratio, vertical cup-to-disc ratio, and horizontal cup-to-disc ratio were 0.46 to 0.53. The ICC was higher for eyes with larger optic discs (0.51) than those with smaller ones (0.32). The ICC calculated using the fixed effects model for the Discam and CSLO comparison was 0.72. Areas under the receiver operator characteristic curves were 0.67 to 0.80 among the three technologies comparing normal with glaucomatous eyes. In general, there was no statistically significant difference between techniques with respect to sensitivity and specificity of glaucoma detection.
  
  
  CONCLUSIONS
  There is good agreement between ONH measurements obtained by Discam, CSLO, and stereography; however, the results are not interchangeable. Similar AROC curve values among all three techniques imply that the Discam, CSLO, and stereography perform equally for the determination of glaucoma status.
authors.affiliation: New England Eye Center, Tufts University School of Medicine, Boston, Massachusetts, USA.
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Correnti
authors.forename: Gadi
authors.initials: G
authors.lastname: Wollstein
authors.forename: Lori Lyn
authors.initials: LL
authors.lastname: Price
authors.forename: Joel S
authors.initials: JS
authors.lastname: Schuman
mesh_terms: D019540:Area Under Curve; D005901:Glaucoma / Q000175:diagnosis*; D006801:Humans; D007834:Lasers; D015233:Models, Statistical; D015588:Observer Variation; D009798:Ocular Hypertension / Q000175:diagnosis; D009887:Ophthalmoscopy / Q000379:methods*; D009898:Optic Disk / Q000473:pathology*; D009901:Optic Nerve Diseases / Q000175:diagnosis*; D010781:Photography / Q000379:methods*; D012372:ROC Curve; D012680:Sensitivity and Specificity; D058609:Visual Field Tests; D014794:Visual Fields