Visualization of Anterior Chamber Angle Structures With Scattering- and Polarization-Sensitive Anterior Segment Optical Coherence Tomography

• Published in: Translational vision science & technology Vol. 10; no. 14; p. 29
• Main Authors: Ueno, Yuta, Mori, Haruhiro, Kikuchi, Keita, Yamanari, Masahiro, Oshika, Tetsuro
• Format: Journal Article
• Language: English
• Published: United States The Association for Research in Vision and Ophthalmology 01.12.2021
• Subjects: Anterior Chamber; Birefringence; Humans; Sclera; Tomography, Optical Coherence; Trabecular Meshwork
• ISSN: 2164-2591; 2164-2591
• DOI: 10.1167/tvst.10.14.29

The purpose of this study was to compare three optical coherence tomography (OCT) modalities in the observation of anterior chamber angle structures; trabecular meshwork (TM), Schlemm's canal (SC), and band of extracanalicular limbal lamina (BELL). Three OCT modalities were used: (1) 2 × 2 Jones-matrix scattering OCT (S-OCT) representing conventional intensity OCT, (2) polarization-diverse S-OCT that was calculated as summation of all elements of the Jones-matrix to eliminate the influence of artifacts caused by sample birefringence, and (3) polarization-sensitive OCT (PS-OCT) to assess depth-resolved phase retardation. In a total of 97 eyes of 55 subjects, nasal and temporal angles were scanned. The detection rate of TM and BELL was significantly different among modalities; highest with PS-OCT (95.1% and 99.2%), followed by 2 × 2 Jones-matrix S-OCT (71.1% and 88.7%) and polarization-diverse S-OCT (33.2% and 25.0%), indicating the influence of artifacts on 2 × 2 Jones-matrix S-OCT measurements. SC was visible with 2 × 2 Jones-matrix S-OCT, polarization-diverse S-OCT, and PS-OCT in 14.2%, 14.9%, and 0.3% of images, respectively. The intergrader agreement as evaluated with the prevalence-adjusted bias-adjusted κ value was higher with PS-OCT than with other S-OCTs. Visibility of anterior chamber angle structures was assessed with three OCT modalities. For TM and BELL that are rich in collagen fibers, PS-OCT provides significantly better visibility than S-OCT without the influence of artifacts arising from polarization or birefringence. Visualization of SC was more difficult with any OCT modalities. PS-OCT is a useful tool to investigate the anterior chamber angle structures which are difficult to observe with conventional OCT.