Imaging limbal and scleral vasculature using Swept Source Optical Coherence Tomography

Abstract

We demonstrate an application of high-speed swept source optical coherence tomography for vessel visualization in the anterior segment of the human eye. The human corneo-scleral junction and sclera was imaged in vivo. Imaging was performed using a swept source OCT system operating at the 1050nm wavelength range and 100kHz A-scan rate. High imaging speed enables the generation of 3D depth-resolved vasculature maps. The vessel visualization method revealed a rich vascular system in the conjunctiva and episclera.

Fig. 1

Swept source OCT system. PC – polarization controller, FC – fiber coupler, SC – galvanometric scanners, CC – corner cube, DC – dispersion compensation.

Fig. 2

OCT cross-sections of the human corneo-scleral region. (a) Structural high-definition scan (protocol A); (b) limbus (protocol B); (c) peripheral sclera (protocol A). C – cornea, S – sclera, E – epithelium, I – iris, SC – Schlemm's canal, OS – ora serrata.

Fig. 3

In vivo 3-D imaging of human limbus. (a) rendering and 3-D reconstruction of data set. (b) C-scan (x-y cross section). Arrows show Schlemm's canal. (c) B-scan in fast scanning axis (y-z cross-section). (d) B-scan in slow scanning axis (x-z cross section). Protocol C from Table 1 was used for scanning the eye. Asterisks show blood vessel shadows.

Fig. 4

Three-dimensional reconstruction of human limbus after flattening (a). En face projection of structural images (b). Virtual C-scans (projections) from angiographic data set showing vascular networks in episclera (c) and deeper sclera (d)-(e). Vasculature rendering after thresholding and colorscale inversion (f). Data set was acquired using protocol D.

Fig. 5

Large area scleral OCT imaging. Composite projection image from 12 individual data sets acquired using protocol D.