Temporal phase evolution OCT for measurement of tissue deformation in the human retina in-vivo

Abstract

We demonstrate the use of temporal phase evolution (TPE-) OCT methods to evaluate retinal tissue deformation in-vivo over time periods of several seconds. A custom built spectral domain (SD)-OCT system with an integrated retinal tracker, ensuring stable imaging with sub-speckle precision, was used for imaging. TPE-OCT measures and images phase differences between an initial reference B-scan and each of the subsequent B-scans of the evaluated temporal sequence. In order to demonstrate the precision and repeatability of the measurements, retinal nerve fiber (RNF) tissue deformations induced by retinal vessels pulsating with the heartbeat were analyzed in several healthy subjects. We show TPE maps (M-scans of phase evolution as a function of position along B-scan trace vs. time) of wrapped phase data and corresponding deformation maps in selected regions of the RNF layer (RNFL) over the course of several cardiac cycles. A reproducible phase pattern is seen at each heartbeat cycle for all imaged volunteers. RNF tissue deformations near arteries and veins up to ∼ 1.6 µm were obtained with an average precision for a single pixel of about 30 nm. Differences of motion induced by arteries and veins are also investigated.

Quantitative Phase Imaging: Recent Advances and Expanding Potential in Biomedicine

“…295 Phasesensitive OCT has also been extended into in vivo imaging of the human retina 296 and its associated motion. 297 However, despite great improvements in phase stability, there is a still often a need for either manual or automatic phase unwrapping to correct for phase errors with this emerging technique.…”

“…OCT and its’ high speed variants are low-coherence interferometry methods that leverage low temporal coherence to exclude scattered light outside a tissue slice of interest, coupled with backscattering of light, to image cross-sectional areas of tissues in situ . , An early approach added phase retrieval to OCT to enable QPI of human cheek cells (Figure a) and isolated chicken cardiomyocytes . Phase-sensitive OCT has also been extended into in vivo imaging of the human retina and its associated motion . However, despite great improvements in phase stability, there is a still often a need for either manual or automatic phase unwrapping to correct for phase errors with this emerging technique.…”

Retinal blood flow imaging with combined full-field swept-source optical coherence tomography and laser Doppler holography

“…It was previously shown that the blood pulsation induces thickness changes that can be monitored with an accuracy that was estimated to 10 nm [6]. This method was used to measure the pulse wave velocity in retinal arteries [6], and recently implemented with scanning instruments [18]. The map of the local changes of retinal thickness between the end of diastole and the following systolic peak [time points indicated by the double headed arrow in Fig.…”