Investigation of post-glaucoma-surgery structures by three-dimensional and polarization sensitive anterior eye segment optical coherence tomography

A sequential case series of post-glaucoma-surgery structures examined by three-dimensional corneal and anterior eye segment optical coherence tomography (3D-CASOCT) and 3D polarization sensitive CASOCT (PS-CASOCT) is presented. A total of 5 patients who underwent glaucoma surgery were included in this study. Of these, 1, 1, and 3 patient underwent trabeculotomy, laser iridotomy, and trabeculectomy respectively. One patient each who had undergone trabeculotomy or laser iridotomy was examined using a prototype 3D-CASOCT. This prototype is based on swept-source OCT technology, uses a probe beam with a center wavelength of 1.31 mu m, and has an axial resolution of 11.6 mu m and a scanning speed of 20,000 A lines/s. All 3 patients who underwent trabeculectomy were examined by PS-CASOCT, which has similar specifications to those of 3D-CASOCT, measures the depth-resolved birefringence of a specimen, and yields conventional OCT images. Detailed 3D visualization of the incision site of trabeculotomy and the ablation site of laser iridotomy was achieved using 3D-CASOCT. PS-CASOCT revealed, in addition to the structural details, the birefringent properties of the tissues of the trabeculectomy bleb. Some blebs showed abnormal birefringence in the conjunctiva and in a remnant fluid pool. This may indicate the existence of fibrosis in these regions. Both 3D-CASOCT and PS-CASOCT provide clinically significant information for the postoperative assessment of structures created during glaucoma surgery. Interactive 3D datasets of all cases are provided for interactive clinical review. Complex raw 3D OCT volumes are also provided as a reference dataset for the development of PS-OCT algorithms. (C) 2009 Optical Society of America