Abstract
Purpose :
To quantify inter-quadrant differences in angle configuration assessed on gonioscopy, Eyecam, and anterior segment optical coherence tomography (AS-OCT) in a cohort of Chinese Americans.
Methods :
Subjects aged 50 years or older were recruited from the Chinese American Eye Study (CHES), a population-based epidemiological study in Los Angeles, CA. Each subject underwent a complete ocular exam including gonioscopy, EyeCam, and AS-OCT under dark ambient lighting. Gonioscopy and AS-OCT imaging were performed by trained ophthalmologists. EyeCam imaging was performed by a trained technician and images were graded by an independent glaucoma specialist.
Results :
709 eyes from 709 subjects were analyzed. Less anatomical variation among the quadrants was detected on gonioscopy and EyeCam compared to AS-OCT (p < 0.05). The mean gonioscopy grade, EyeCam grade, and AS-OCT measurement for each quadrant varied by up to 10.3%, 6.4%, and 46.2% of the superior quadrant value, respectively. There were significant inter-quadrant differences (p < 0.05) among mean AOD750 measurements when grouping by quadrant and gonioscopy or EyeCam grade. Mean AOD750 measurements were smallest for the superior quadrant by between 14.3% to 38.1% and 17.4% to 37.9% on gonioscopy and EyeCam, respectively, compared to other quadrants. Angle Visibility Index (AVI) values were largest for the superior quadrant.
Conclusions :
Gonioscopy and EyeCam significantly under-represent anatomical variations of the ACA compared to AS-OCT, likely due to differences in the visibility of anatomical structures among the quadrants. These findings suggest that gonioscopy or EyeCam grades from different quadrants are not comparable or interchangeable, which supports reconsideration of current definitions and methods used to diagnose and manage primary angle closure disease (PACD).
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.