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

Prcis: Three-dimensional (3D) angle parameters and cutoff values for detecting angle closure were proposed. The 3D parameters demonstrated excellent diagnostic performance. Certain horizontal two-dimensional (2D) parameters [ie, trabecular iris space area (TISA)-750, angle opening distance (AOD)-750, and AOD-500] can attain similar performance to their high-performing 3D counterparts.

Objective: To investigate the diagnostic performance of single horizontal 2D versus 3D angle parameters from swept-source anterior segment optical coherence tomography (CASIA2) in detecting angle closure.

Materials and methods: The cross-sectional study included 118 phakic patients (59 open angles, 59 closed angles). AOD, angle recess area (ARA), and TISA at 250, 500, and 750 μm from scleral spur were measured in 360-degree radial-scan images. The 3D information of each measurement was analyzed in 2 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 the receiver operating characteristic curve [areas under the curve (AUCs)] of eighteen 3D parameters were compared with 2D horizontal parameters.

Results: Among 3D parameters, AOD-500 estimate 3D gave the highest AUC (AUC: 0.950, cutoff: 6.09 mm 2 ), followed by AOD-750 estimate 3D (AUC: 0.948, cutoff: 8.26 mm 2 ). 3D parameters significantly increased the AUC of ARA-250 and TISA-250 (all P < 0.02) compared with the 2D parameters. No significant improvement in AUC was demonstrated for AOD-250 and all parameters at 500 and 750 μm. No significant difference in AUC was found among the 6 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.

Conclusions: 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.