Birefringence Imaging of Anterior Eye by Three-Dimensional Polarization Sensitive Anterior Eye Segment Optical Coherence Tomography

Abstract

 

Purpose:

 

Current anterior eye segment optical coherence tomography (AS-OCT) visualizes the structures of anterior eye based on their optical scattering properties. Although AS-OCT has great potential for clinical imaging of the anterior eye, it is not always easy to detect some important structures and properties of the tissue, e.g., trabecular meshwork, sclera, and the tissue with fibrosis. In this study, we employ a new three-dimensional polarization-sensitive AS-OCT (3-D PS-OCT), and demonstrate the ability of selective visualization of the trabecular meshwork, sclera, and the tissue with fibrosis.

 

Methods:

 

AS-OCT based on swept-source OCT technology at 1.3 um wavelength with polarization sensitivity was newly developed. This 3-D PS-OCT visualizes the phase retardation, axis orientation and diattenuation of the sample. In contrast to the previous fiber-based PS-OCT, our PS-OCT can set an arbitrary transversal scanning range. Three eyes of two cases of trabeculectomy and two eyes of two healthy volunteers were examined by the 3-D PS-OCT.

 

Results:

 

The figure shows the OCT (upper/lower left) and phase retardation images (upper/lower right) of a normal angle and a bleb, respectively. The positions of the trabecular meshwork and superior rectus muscle were selectively visualized based on their birefringence properties (2 of 2 normal eyes). The sclera was selectively contrasted, thus the sclero-tennon junction was successfully visualized (2 of 2 normal eyes). The tissue surrounding the fluid filled space showed characteristic phase retardation patterns (3 of 3 eyes after trabeculectomy).

 

Conclusions:

 

PS-OCT selectively contrasts the trabecular meshwork and the sclera as well as the fibrotic tissues in the bleb. It may be clinically useful for the screening of glaucoma and effective follow-up of glaucoma surgeries.  

 

Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • trabecular meshwork • sclera