Reproducibility of Anterior Chamber Angle Measurements with Anterior Segment Optical Coherence Tomography

Annelie N. Tan, Loes D. C. Sauren, John de Brabander, Tos T. J. M. Berendschot, Valéria Lima Passos, Carroll A. B. Webers, Rudy M. M. A. Nuijts, Henny J. M. Beckers
2011 Investigative Ophthalmology and Visual Science  
PURPOSE. To study the reproducibility and variability of iridocorneal angle (ICA) measurements by using anterior segment optical coherence tomography (AS-OCT) by expert and nonexpert observers. METHODS. Twenty-three healthy volunteers (nonexperts with a basic knowledge of ophthalmology) acquired five consecutive AS-OCT images in the enhanced anterior segment single mode in the 180°to 0°meridian of the right eyes of their peers. Two experts and the 23 nonexperts analyzed the images. The ICA
more » ... mages. The ICA software tool was used to determine the angle opening distance (AOD) and the trabecular iris surface area (TISA) at 500 and 750 m. A random intercept model was fitted to evaluate the variability of acquiring an image. For both the experts and the nonexperts, inter-and intraobserver variability of analyzing an AS-OCT image was determined with the coefficient of variation (CV). Reproducibility was qualified by using the intraclass correlation coefficient (ICC). RESULTS. There was no statistically significant difference in the variability of acquiring an image. The range of intraobserver variability in image analysis was from 9.4% to 12.5% in the experts and from 4.2% to 17.4% in the nonexperts. Interobserver variability was 10.7% in the experts and 10.2% in the nonexperts. The reproducibility was high, 0.875 and 0.942 in the experts and 0.906 in the nonexperts. CONCLUSIONS. The overall reproducibility of the ICA measurements with the AS-OCT is good in open angles. Inter-and intraobserver variability showed similar mean values of reproducibility between the experts and nonexperts. The wide range of intraobserver variation in the nonexperts suggests that this group should undergo extensive instruction before routinely analyzing AS-OCT images. (Invest Ophthalmol Vis Sci. A lthough the current gold standard to assess the iridocorneal angle (ICA) is gonioscopy, this procedure is relatively invasive for the patient and the result relies on the physician's subjective assessment and experience. 1
doi:10.1167/iovs.10-5872 pmid:20881302 fatcat:akvcykqd4ne37emt5y24lqldsq