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PURPOSE: To compare anterior chamber angle parameters based on the location of Schwalbe line (SL) from 2 spectral domain optical coherence tomography (SD-OCT) instruments and to measure their reproducibility. METHODS: Forty-two eyes from 21 normal, healthy participants underwent imaging of the inferior irido-corneal angle with the Spectralis and Cirrus SD-OCT under tightly controlled low-light conditions. SL-angle opening distance (SL-AOD) and SL-trabecular iris space area (SL-TISA) were measured by masked, certified graders at the Doheny Imaging Reading Center using customized grading software. Interinstrument and intrainstrument, as well as interobserver and intraobserver reproducibility of SL-AOD and SL-TISA measurements were evaluated by intraclass correlation coefficients (ICCs) and Bland-Altman plots with limits of agreement (LoA). RESULTS: The mean SL-AOD was 0.662±0.191 mm in Spectralis and 0.677±0.213 mm in Cirrus. The mean SL-TISA was 0.250±0.073 mm in Spectralis and 0.256±0.082 mm in Cirrus. The agreement for intrainstrument (ICCs>0.979), intragrader (ICCs>0.992), and intergrader (ICCs>0.929) was excellent. Excellent agreement between the 2 devices was also documented with a mean difference of -0.016 (LoA -0.125 to 0.092) mm for SL-AOD and -0.007 (LoA -0.056 to 0.043) mm in SL-TISA. CONCLUSIONS: Both SD-OCTs provided comparable measurements and permitted calculation of SL-based angle metrics. There was excellent interinstrument and intrainstrument and intraobserver and interobserver reproducibility for Spectralis and Cirrus SD-OCTs, suggesting true interchangeability between SD-OCT devices. This has the potential to lead to development of standardized grading assessments and quantification of angle parameters that would be valid across various SD-OCT devices.This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially.http://creativecommons.org/licenses/by-nc-nd/4.0/.
*Doheny Image Reading Center, Doheny Eye Institute ‡Department of Ophthalmology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA †The Affiliated Hospital of Medical College, Qingdao University Qingdao, Shandong, P.R. China.
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