Diagnostic Abilities of Three-dimensional Anterior Segment Optical Coherence Tomography in Detecting Angle Closure.

Abstract

3D-angle parameters and cutoff values for detecting angle closure were proposed. The 3D parameters demonstrated excellent diagnostic performance. Certain horizontal 2D parameters (i.e.,TISA-750, AOD-750, and AOD-500) can attain similar performance to their high-performing 3D counterparts. To investigate the diagnostic performance of single horizontal 2-dimensional (2D) versus 3-dimensional (3D) angle parameters from swept-source anterior segment optical coherence tomography (CASIA2) in detecting angle closure. The cross-sectional study included 118 phakic subjects (59 open-angle, 59 closed-angle). Angle opening distance (AOD), angle recess area (ARA), trabecular-iris space area (TISA) at 250, 500, and 750μm from scleral spur were measured in 360° radial-scan images. The 3D information of each measurement was analyzed in two patterns: (1) average 3D parameter - the averaged value from 360-degree angle values, and (2) estimate 3D parameter - the estimation of surface area of circumferential angle inlet (using AOD) or circumferential angle volume (using ARA and TISA). The areas under receiver operating curve (AUCs) of eighteen 3D parameters were compared with 2D horizontal parameters. Among 3D parameters, AOD-500 estimate 3D gave the highest AUC (AUC 0.950, cut-off 6.09mm2), followed by AOD-750 estimate 3D (AUC 0.948, cut-off 8.26mm2). 3D parameters significantly increased the AUC of ARA-250 and TISA-250 (all P<0.02) compared to the 2D parameters. No significant improvement in AUC was demonstrated for AOD-250 and all parameters at 500 and 750μm. No significant difference in AUC was found among the six maximum AUC parameters which were AOD-750 horizontal 2D, AOD-500 estimate 3D, TISA-750 horizontal 2D, AOD-500 horizontal 2D, AOD-750 estimate 3D and TISA-750 average 3D. The 3D-angle parameters had high performance in detecting angle closure. However, comparing a horizontal measurement to 3D parameters, the AUC improvement was mostly insignificant.