Abstract
Purpose :
To evaluate the inter- and intra-observer reproducibility of anterior chamber (AC) angle measurements obtained by swept-source optical coherence tomography (SS-OCT).
Methods :
Fifty-eight eyes with primary angle closure suspect (PACS) were selected for high quality angle imaging with SS-OCT. Three experienced observers measured: (1) anterior segment volume, including corneal, AC, and iris volume (CV, ACV, IV); (2) anterior segment dimensions, including AC depth and width (ACD, ACW), and lens vault (LV) at 0-180°, 45-225°, 90-270°, 135-315° axis; and (3) angle parameters, including angle opening distance (AOD), angle recess area (ARA), trabecular iris space area (TISA), and the trabecular iris angle (TIA) at 0°, 45°, 90°, 135°, 180°, 225°, 270°, 315° angle. One observer measured all parameters twice to evaluate the intra-observer reliability. Intraclass correlation coefficient (ICC) was calculated for each parameter.
Results :
For inter-observer reproducibility, ICCs of CV, ACV, and IV were 1.000, 1.000 and 0.996 respectively. ICC of ACD at the 90-270° axis was 0.639 while ICCs of other degrees ranged from 0.979 to 0.994. ACW and LV also had smallest ICCs at the 90°-270° axis (0.952 and 0.812). ICC of ARA 250 µm from the scleral spur was the smallest (0.684) compared to 500 µm and 750 µm from the scleral spur (0.828, 0.882). Similarly, TISA and TIA at all angles had smallest ICCs 250 µm from the scleral spur. ICCs of AOD of all angles ranged from 0.920 to 0.984 without significant differences based on distance from scleral spur. For intra-observer reproducibility, all ICCs ranged from 0.812 to 1.000.
Conclusions :
For inter-observer reproducibility, SS-OCT has high level of agreement for anterior segment volume parameters. Measurement of anterior segment dimensions correlated well except for measurements taken along the 90-270° axis, which may be due to the effect of eyelid position. In addition, angle measurements taken 250 µm from the scleral spur vary more than those taken 500 µm and 750 µm from the scleral spur. Intra-observer reproducibility was high for all parameters.
This is a 2020 ARVO Annual Meeting abstract.