High Speed Swept Source Optical Coherence Tomography of Human Choroidal Vasculature In Vivo at 1060 nm

Abstract

 

Purpose:

 

To investigate the retinal and choroidal vascular pattern and structure over wide-angle using high-speed, high axial resolution swept source optical coherence tomography (SS-OCT) at 1060 nm with enhanced penetration through complete choroidal layers.

 

Methods:

 

An ophthalmic SS-OCT system operating at a speed of 57,000 axial scans per second with 5.9 µm axial resolution was developed. Depth-integrated enface reflectance images were extracted at different depths to resolve all retinal and choroidal vasculature networks as well as substructure up to a scanning angle of ~70°×35°.

 

Results:

 

The retinal layers, choriocapillaris (CC), Sattler’s layer (SL), Haller’s layer (HL), and the avascular lamina suprachoroid layer (LSL) were delineated in 2D sagittal tomograms. The sagittal tomograms and enface reflectance images over 2 cm² field of view visualized the paraoptic, lateral and medial distal short posterior ciliary arteriy (SPCA) branches as well as two lateral and medial long posterior ciliary arteries (LPCAs). Enface images in the HL revealed the superotemporal, inferotemporal, superonasal, and inferonasal major choroidal veins draining the macular into symmetric lateral and asymmetric medial drainage systems. Arterial and venous watershed zones were identifiable by vessels distribution in the HL. Figure shows the depth-integrated reflectance enface view at the level of Haller’s layer over 1 cm² lateral sector of the optic nerve head illustrating large superotemporal and inferotemporal draining veins as wells as ciliary artery branches.

 

Conclusions:

 

High speed, high resolution SS-OCT centered at 1060 nm is able to visualize the retinal and choroidal vasculature network including retina vessels, posterior ciliary artery (PCA) branches and venous vascular pattern. This technology potentially provides great diagnostic abilities to monitor change in these networks, substructure and watershed zones during disease initiation and progression.  

 

Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • choroid • retina