Digital Gonioscopy based on Three-dimensional Anterior Segment Optical Coherence Tomography: an international multicenter study.

Abstract Objective To develop and evaluate the performance of a three-dimensional deep-learning based automated digital gonioscopy system (3D DGS) in detecting two major characteristics in eyes suspected to have primary angle closure glaucoma (PACG): 1) narrow iridocorneal angles (static gonioscopy, Task I) and; 2) peripheral anterior synechiae (PAS) (dynamic gonioscopy, Task II) on optical coherence tomography scans. Design International cross-sectional multicentre study. Subjects A total of 1.112 million images of 8694 volume scans (2294 patients) from three centers were included in this study (Task I: training/internal validation/external testing – 4515, 1101, 2222 volume scans respectively; Task II: training/internal validation/external testing – 378, 376, 102 volume scans respectively). Methods For Task I, a narrow angle was defined as an eye in which the posterior pigmented trabecular meshwork not visible in more than 180 degrees without indentation in the primary position captured in the dark room from the scans. For Task II, PAS was defined as the adhesion of the iris to the trabecular meshwork. The diagnostic performance of the 3D DGS was evaluated in both tasks with gonioscopic records as reference. Main Outcome Measures The area under curve (AUC), sensitivity and specificity of the 3D DGS were calculated. Results In Task I, 29.4% patients had narrow angle. The AUC, sensitivity and specificity of 3D DGS on the external testing datasets were 0.943 (0.933-0.953), 0.867 (0.838-0.895), and 0.878 (0.859-0.896), respectively. For Task II, 13.8% patients had PAS. The AUC, sensitivity and specificity of 3D DGS were 0.902 (0.818-0.985), 0.900 (0.714-1.000), 0.890 (0.841-0.938) on the external testing set, at quarter level following normal clinical practice; and 0.885 (0.836-0.933), 0.912(0.816-1.000) and 0.700 (0.660-0.741) on the external testing set, at clock-hour level. Conclusions The 3D DGS is effective in detecting the eyes suspected to have PACG. It has the potential to be used widely in the primary eye care community for screening of the subjects at high risk of developing PACG.