Three-Dimensional Imaging of Trabeculectomy Blebs Using Swept-Source Optical Coherence Tomography

Abstract

Purpose: : To evaluate three-dimensional images of trabeculectomy blebs using Swept-Source optical coherence tomography (SS-OCT).

Methods: : Our SS-OCT system utilizes superstructure-grating distributed Bragg reflector (SSG-DBR) laser, developed at NTT Photonics Laboratories. SSG-DBR laser has characteristics of scanning wavelength with discrete stepwise tuning and consequently the interference length became longer than ordinary SS-OCT system used a light source with a continuous range of scanning wavelength. Three-dimensional imagings of trabeculectomy blebs were performed with sufficient depth ranges.

Results: : The tuning range of SSG-DBR laser, set from 1560 to 1640 nm with an increment of 0.1 nm tuning step, which is also the same as the L-LL band used in the telecommunication market, enables SS-OCT to provide an axial resolution of less than 10 µm in the ocular tissue. Because of its high frequency interval (16.5 GHz) and high scanning speed (15 KHz A-line rate), the imaging analysis in depth of 6 mm became possible. Five blebs in eyes of five patients were imaged. Two avascular blebs had fluid-filled spaces, and the images clearly showed distinct layers in the blebs.

Conclusions: : The SS-OCT demonstrated a three-dimensional imaging of trabeculectomy blebs. We were able to observe details of blebs in all subjects. The imaging obtained by SS-OCT may be useful for evaluating functions of trabeculectomy blebs.

Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • anterior segment • anterior chamber