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L. S. Lim, L. M. Sakata, H. T. Aung, A. Tsai, M.-G. He, T. Aung; Reproducibility of Anterior Chamber Angle Measurements Using Zhongshan Angle Assessment Program Applied to Visante Anterior Segment Optical Coherence Tomography Images. Invest. Ophthalmol. Vis. Sci. 2008;49(13):5086.
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© ARVO (1962-2015); The Authors (2016-present)
To determine the reproducibility of angle measurements by Visante anterior segment optical coherence tomography (ASOCT; Carl Zeiss Meditec Inc, Dublin, CA) using the newly developed Zhongshan Angle Assessment Program (ZAAP; Guangzhou, China).
ASOCT scans of the nasal and temporal angles were obtained in dark conditions. Two consecutive scans were obtained by a single observer to determine short-term intra-observer variability and a third scan was obtained by a second observer to determine inter-observer variability. A second set of scans was obtained by the same observer after at least one week to determine long-term intra-observer variability. Inter-device reproducibility was also assessed by obtaining a further set of images using a second Visante ASOCT device. A single examiner obtained the angle opening distance at 500 um (AOD500), angle recess area (ARA), and trabecular-iris space area at 500um (TISA500) using the ZAAP software. All images from the same patient were analyzed in sequence to minimize variability in the determination of scleral spur location. To evaluate test-retest variability, limits of agreement (LOA) (Bland-Altman plots) and intraclass correlation coefficient (ICC) were obtained.
A total of 37 eyes of 37 subjects were included in the study. The ICC for the short- and long-term intra-operator analyses ranged from 0.93 - 0.96 and 0.91 - 0.93, respectively. The ICC for the inter-operator and inter-device analyses ranged from 0.90 - 0.93 and 0.91 to 0.94 respectively. The Table shows the bias and 95% LOA for the angle measurements obtained at the nasal angle.
Angle measurements by the Visante ASOCT using the ZAAP software showed good inter-observer, short and long-term intra-observer, and inter-device reproducibility.
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