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

Abstract

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 microm, and has an axial resolution of 11.6 microm 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 3DCASOCT, 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.

Scleral birefringence as measured by polarization-sensitive optical coherence tomography and ocular biometric parameters of human eyes in vivo

“…PS-OCT has been used to measure birefringence of cornea [19], trabecular meshwork [20], retinal nerve fibers [21][22][23], and scarred tissue of age-related macular degeneration [24]. PS-OCT has also been used to investigate birefringence of pterygium and scarred tissue of the conjunctiva after trabeculectomy [25,26]. Although it is known that the sclera has high birefringence in both the anterior and posterior segments of the eye [27][28][29], the association of scleral birefringence with ocular diseases has not been investigated to date except in one case study of necrotizing scleritis [30].…”

Birefringence measurement of cornea and anterior segment by office-based polarization-sensitive optical coherence tomography

“…However, it has been difficult to diagnose the functioning of the bleb using the conventional imaging methods. PS-OCT may be able to diagnose the scar tissue after the surgery [17].…”

Early trabeculectomy bleb walls on anterior-segment optical coherence tomography

“…Bleb appearance has been assessed using slit-lamp biomicroscopy [1][2][3], ultrasound biomicroscopy (UBM) [4][5][6][7][8], and optical coherence tomography (OCT) [9][10][11][12][13][14][15][16][17][18]. Picht and Grehn [1] reported that trabeculectomy is more likely to have a better outcome if the filtering bleb appears on slit-lamp biomicroscopy to have more microcysts, fewer conjunctival and corkscrew vessels, is not encapsulated, and is lower in height.…”