Assessment of Optic Disc Cupping With Digital Fundus Photographs

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. Diagnostic test comparison. 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. 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. 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.