Evaluation of the Narrow Anterior Chamber Angle by Anterior Segment Optical Coherence Tomography

The aim of this work was to evaluate the narrow anterior chamber angle (ACA) in Chinese patients by anterior segment optical coherence tomography (As-OCT).

Eighty right eyes of 80 consecutive patients with a shallow peripheral anterior chamber but no peripheral anterior synechia were enrolled in this study. The ACA was observed by noncompression gonioscopy and classified according to the Shaffer grading system. The iridotrabecular contact (ITC) and trabecular-iris angle (T-I angle) were assessed by As-OCT examination.

Gonioscopic grade 0 and ITC were observed more frequently in the superior quadrant than the other quadrants (p < 0.02). The T-I angle was significantly smaller superiorly and inferiorly than nasally and temporally (p < 0.01). The frequency of the ITC and T-I angle significantly declined when the gonioscopic grade was from 0 to 2 (p < 0.01). Logistic analysis showed that the axial length and refraction were related to the presence of ITC in more than two quadrants (p < 0.03).

ITC was common in eyes with a shallow peripheral anterior chamber (superiorly, gonioscopic grade 0). Sites with wider gonioscopic grading tended to have a larger T-I angle. Axial length and refraction significantly impacted on the frequency of ITC.