Swept Source OCT imaging of limbal and sclera vessels in vivo using speckle variance detection

Abstract

 

Purpose

 

To demonstrate in vivo imaging of limbal and scleral blood vessels using Swept Source Optical Coherence Tomography and speckle variance processing.

 

Methods

 

Patients with different anterior eye pathologies were imaged at the New England Eye Center using a prototype 1050 nm swept source OCT with 6um axial resolution and 100kHz axial scan speed. Volumetric raster scans (consisting of 200 x 200 A-scans x 3 repeated B-scans) were obtained over a 3 mm x 3 mm area of sclera located just posterior to the horizontal and vertical limbus. Visualization of blood vessels was enhanced using “speckle variance”, an acquisition and processing technique wherein repeated B-scans are acquired, and the deccorelation of speckle patterns over these repeated B-scans is calculated. After correcting for bulk motion, remaining motion due to blood flow results in increased variance of speckle patterns, enabling visualization of small vessels that are not discernible using standard structural imaging.

 

Results

 

Using speckle variance OCT at 1050nm, high quality en face imaging of the limbal and sclera vessels was achieved, with superior visualization of vasculature compared with standard structural images.

 

Conclusions

 

Swept source OCT with speckle variance processing enhances the ability to image limbal and sclera vessels. This has potential use in identifying and monitoring various ischemic and inflammatory ocular diseases in which the limbal vasculature is involved.

 

 

Standard en face OCT image from volume.

 

 

En face OCT with speckle variance processing.

 

Keywords: 552 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • 421 anterior segment • 550 imaging/image analysis: clinical