Intraobserver and Interobserver Agreement in Measurement of Optic Disc Characteristics

James M. Tielsch, Joanne Katz, Harry A. Quigley, Neil R. Miller, Alfred Sommer

Research output: Contribution to journalArticlepeer-review

213 Scopus citations


Reliable measures of optic nerve status are important parameters for epidemiologic and clinical studies of glaucoma. Stereo fundus photography has been used to reduce Interobserver variation, but little data have been reported quantifying the level of agreement in these situations. This article examines chance-corrected Intraobserver and Interobserver agreement for horizontal and vertical cup:disc ratios and width of the narrowest remaining neuroretinal rim on stereo, color, fundus photographs. Intraobserver agreement was substantial to almost perfect for both readers (kappas between 0.82 and 0.86 for horizontal and vertical cup:disc ratios and 0.71 for the neuroretinal rim). Interobserver agreement was also substantial (kappas of 0.71 for horizontal cup:disc ratio, 0.74 for vertical cup:disc ratio, and 0.58 for the neuroretinal rim). Both Intraobserver and Interobserver agreement were best for glaucoma patients followed by ocular hypertensives and controls. Dichotimizing cup:disc ratios into suspicious or not suspicious using a range of cutoff points (≥0.5, ≥0.6, and ≥0.7 disc diameters [DD]) had little effect on agreement levels. Estimation of the status of the optic nerve is complex, requiring judgment about the shape and structure of the cup. Agreement is optimized by using stereo photographs, using the same observer and, when evaluating progression, comparing photographs from different points in time at a single sitting.

Original languageEnglish (US)
Pages (from-to)350-356
Number of pages7
Issue number3
StatePublished - 1988


  • cup:disc ratio
  • measurement
  • optic nerve

ASJC Scopus subject areas

  • Ophthalmology


Dive into the research topics of 'Intraobserver and Interobserver Agreement in Measurement of Optic Disc Characteristics'. Together they form a unique fingerprint.

Cite this