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Abstract #6650 Published in IGR 4-1
Observer experience and Cup:Disc ratio assessment
Hanson S; Krishnan SK; Phillips JOptometry and Vision Science 2001; 78: 701-705
BACKGROUND: The validity of the cup-disc (C:D) ratio as a clinical measure depends on the level of agreement among observers. In this study, the authors investigated the effect of observer experience on interobserver and intraobserver agreement in C:D ratio estimation. METHODS: Nine third-year (Yr3) and nine fourth-year (Yr4) optometry students and nine optometrists (Opt), determined C:D ratios from 26 optic disc photographs viewed monoscopically and stereoscopically. Observer agreement was investigated using weighted kappa (Kw) analysis. RESULTS: Interobserver agreement was higher (p < 0.01) among optometrists than among fourth-year students and higher (p < 0.01) among fourth-year than among third-year students (mean Kw: Opt = 0.61; Yr4 = 0.51; Yr3 = 0.39). Stereoscopic estimates of C:D ratios were higher (p < 0.0001) than monoscopic estimates, and interobserver agreement was higher (p < 0.001) when evaluating the vertical rather than the horizontal C:D ratio. Intraobserver agreement (mean Kw: Opt = 0.67; Yr4 = 0.66; Yr3 = 0.62) did not vary significantly (p = 0.78) with experience. CONCLUSIONS: The extent to which an observer reproducibly assesses the C:D ratio from optic disc photographs (intraobserver agreement) does not increase with experience. However, the agreement between different observers in assessing the C:D ratio (interobserver agreement) increases with experience.
Dr. S. Hanson, Department of Optometry and Vision Science, The University of Auckland, Auckland, New Zealand
Classification:
2.14 Optic disc (Part of: 2 Anatomical structures in glaucoma)
6.8.2 Posterior segment (Part of: 6 Clinical examination methods > 6.8 Photography)
