title: Assessment of optic disc cupping with digital fundus photographs.
abstract: OBJECTIVE
  To determine the agreement between the assessment of retinal digital images by using an overlay transparency sheet and the Heidelberg retinal tomograph (HRT) in determining cup-disk ratios greater than 0.6.
  
  
  METHODS
  Diagnostic test comparison.
  
  
  METHODS
  Computerized topographic and monoscopic digital images of the optic disk of 628 people aged 70 to 79 years were assessed. A grader (M.C.) defined the disk margin on HRT images, and the operation software computed the area cup-disk ratio. The same grader also determined whether the vertical cup-disk ratio on retinal images was greater than 0.6 by superimposing a transparency overlay sheet over the images. Findings of a second grader (J.G.F.) were used to establish reliability measures.
  
  
  RESULTS
  The intragrader reliability for the overlay method and HRT was almost perfect (intraclass correlation coefficient [ICC] = 0.96 and 0.99, respectively), whereas the intergrader reliability was good (ICC = 0.77 and 0.92, respectively). A perfect agreement was found on 28 (85%) of 33 eyes between the overlay and HRT methods in determining cup-disk ratios greater than 0.6.
  
  
  CONCLUSIONS
  The overlay transparency method appears to be a reliable and promising alternative in determining cup-disk ratios greater than 0.6 in a community screening setting.
authors.affiliation: Centre for Eye Research Australia, University of Melbourne, Royal Victorian Eye and Ear Hospital, 32 Gisborne Street, East Melbourne, Victoria 3002, Australia. mariosc@unimelb.edu.au
authors.forename: Marios
authors.initials: M
authors.lastname: Constantinou
authors.forename: John G
authors.initials: JG
authors.lastname: Ferraro
authors.forename: Ecosse L
authors.initials: EL
authors.lastname: Lamoureux
authors.forename: Hugh R
authors.initials: HR
authors.lastname: Taylor
mesh_terms: D000368:Aged; D005901:Glaucoma / Q000175:diagnosis*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D015588:Observer Variation; D009898:Optic Disk / Q000473:pathology*; D009901:Optic Nerve Diseases / Q000175:diagnosis*; D010781:Photography / Q000379:methods*; D015203:Reproducibility of Results