AIMS: The development of imaging and measurement techniques has brought the prospect of greater objectivity in the measurement of optic disc features, and therefore better agreement between observers. The purpose of this study was to quantify and compare the variation between observers using two measurement devices. METHODS: Optic disc photographs and images from the Heidelberg retina tomograph (HRT) of 30 eyes of 30 subjects were presented to six observers for analysis, and to one observer on five separate occasions. Agreement between observers was studied by comparing the analysis of each observer with the median result of the other five, and expressed as the mean difference and standard deviation of differences between the observer and the median. Inter- and intraobserver variation was calculated as a coefficient of variation (mean SD/mean x 100). RESULTS: For planimetry, agreement between observers was dependent on observer experience, for the HRT it was independent. Agreement between observers (SD of differences as a percentage of the median) for optic disc area was 4.0% to 7.2% (planimetry) and 3.3% to 6.0% (HRT), for neuroretinal rim area it was 10.8% to 21.0% (planimetry) and 5.2% to 9.6% (HRT). The mean interobserver coefficient of variation for optic disc area was 8.1% (planimetry) and 4.4% (HRT), for neuroretinal rim area it was 16.3% (planimetry) and 8.1% (HRT), and (HRT only) for rim volume was 16.3%, and reference height 9.1%. HRT variability was greater for the software version 1.11 reference plane than for version 1.10. The intraobserver coefficient of variation for optic disc area was 1.5% (planimetry) and 2.4% (HRT), for neuroretinal rim area it was 4.0% (planimetry) and 4.5% (HRT). CONCLUSIONS: Variation between observers is greatly reduced by the HRT when compared with planimetry. However, levels of variation, which may be clinically significant, remain for variables that depend on the subjective drawing of the disc margin.
AIMS: The development of imaging and measurement techniques has brought the prospect of greater objectivity in the measurement of optic disc features, and therefore better agreement between observers. The purpose of this study was to quantify and compare the variation between observers using two measurement devices. METHODS: Optic disc photographs and images from the Heidelberg retina tomograph (HRT) of 30 eyes of 30 subjects were presented to six observers for analysis, and to one observer on five separate occasions. Agreement between observers was studied by comparing the analysis of each observer with the median result of the other five, and expressed as the mean difference and standard deviation of differences between the observer and the median. Inter- and intraobserver variation was calculated as a coefficient of variation (mean SD/mean x 100). RESULTS: For planimetry, agreement between observers was dependent on observer experience, for the HRT it was independent. Agreement between observers (SD of differences as a percentage of the median) for optic disc area was 4.0% to 7.2% (planimetry) and 3.3% to 6.0% (HRT), for neuroretinal rim area it was 10.8% to 21.0% (planimetry) and 5.2% to 9.6% (HRT). The mean interobserver coefficient of variation for optic disc area was 8.1% (planimetry) and 4.4% (HRT), for neuroretinal rim area it was 16.3% (planimetry) and 8.1% (HRT), and (HRT only) for rim volume was 16.3%, and reference height 9.1%. HRT variability was greater for the software version 1.11 reference plane than for version 1.10. The intraobserver coefficient of variation for optic disc area was 1.5% (planimetry) and 2.4% (HRT), for neuroretinal rim area it was 4.0% (planimetry) and 4.5% (HRT). CONCLUSIONS: Variation between observers is greatly reduced by the HRT when compared with planimetry. However, levels of variation, which may be clinically significant, remain for variables that depend on the subjective drawing of the disc margin.
Authors: Edward Lai; Gadi Wollstein; Lori Lyn Price; Lelia A Paunescu; Paul C Stark; James G Fujimoto; Joel S Schuman Journal: Ophthalmic Surg Lasers Imaging Date: 2003 Nov-Dec
Authors: L Guo; V Tsatourian; V Luong; A G Podoleanu; A G Podolean; D A Jackson; F W Fitzke; M F Cordeiro Journal: Br J Ophthalmol Date: 2005-09 Impact factor: 4.638
Authors: Manuel M Hermann; David F Garway-Heath; Christian P Jonescu-Cuypers; Reinhard O W Burk; Jost B Jonas; Christian Y Mardin; Jens Funk; Michael Diestelhorst Journal: Int Ophthalmol Date: 2007-02-06 Impact factor: 2.031
Authors: Juan Xu; Hiroshi Ishikawa; Gadi Wollstein; Richard A Bilonick; Kyung R Sung; Larry Kagemann; Kelly A Townsend; Joel S Schuman Journal: Invest Ophthalmol Vis Sci Date: 2008-03-07 Impact factor: 4.799
Authors: Anita Manassakorn; Hiroshi Ishikawa; Jong S Kim; Gadi Wollstein; Richard A Bilonick; Larry Kagemann; Michelle L Gabriele; Kyung Rim Sung; Tarkan Mumcuoglu; Jay S Duker; James G Fujimoto; Joel S Schuman Journal: Arch Ophthalmol Date: 2008-01
Authors: Michelle L Gabriele; Gadi Wollstein; Richard A Bilonick; Zvia Burgansky-Eliash; Hiroshi Ishikawa; Larry E Kagemann; Joel S Schuman Journal: Ophthalmology Date: 2007-08-27 Impact factor: 12.079