scholarly journals Akinetic Swept-Source Master–Slave-Enhanced Optical Coherence Tomography

Photonics ◽  
2021 ◽  
Vol 8 (5) ◽  
pp. 141
Author(s):  
Manuel J. Marques ◽  
Ramona Cernat ◽  
Jason Ensher ◽  
Adrian Bradu ◽  
Adrian Podoleanu
Keyword(s):  
Optical Coherence Tomography ◽  
Sampling Rate ◽  
Calibration Procedure ◽  
Depth Information ◽  
Optical Coherence ◽  
Time Intervals ◽  
Swept Source ◽  
High Sampling Rate ◽  
First Time ◽  
Down Conversion

This paper presents a different approach for processing the signal from interferometers driven by swept sources that exhibit non-linear tuning during stable time intervals. Such sources are, for example, those commercialised by Insight, which are electrically tunable and akinetic. These Insight sources use a calibration procedure to skip frequencies already included in a spectral sweep, i.e., a process of “clearing the spectrum”. For the first time, the suitability of the Master–Slave (MS) procedure is evaluated as an alternative to the conventional calibration procedure for such sources. Here, the MS process is applied to the intact, raw interferogram spectrum delivered by an optical coherence tomography (OCT) system. Two modalities are investigated to implement the MS processing, based on (i) digital generation of the Master signals using the OCT interferometer and (ii) down-conversion using a second interferometer driven by the same swept source. The latter allows near-coherence-limited operation at a large axial range (>80 mm), without the need for a high sampling rate digitiser card to cope with the large frequency spectrum generated, which can exceed several GHz. In both cases, the depth information is recovered with some limitations as described in the text.

scholarly journals A Novel Automatic Method to Estimate Visual Acuity and Analyze the Retinal Vasculature in Retinal Vein Occlusion Using Swept Source Optical Coherence Tomography Angiography

2019 ◽  
Vol 8 (10) ◽  
pp. 1515 ◽  
Author(s):  
Díez-Sotelo ◽  
Díaz ◽  
Abraldes ◽  
Gómez-Ulla ◽  
Penedo ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Visual Acuity ◽  
Optical Coherence Tomography Angiography ◽  
Foveal Avascular Zone ◽  
Depth Information ◽  
Vascular Density ◽  
Optical Coherence ◽  
Automatic Method ◽  
Correlation Index ◽  
Swept Source

The assessment of vascular biomarkers and their correlation with visual acuity is one of the most important issues in the diagnosis and follow-up of retinal vein occlusions (RVOs). The high workloads of clinical practice make it necessary to have a fast, objective, and automatic method to analyze image features and correlate them with visual function. The aim of this study is to propose a fully automatic system which is capable of estimating visual acuity (VA) in RVO eyes, based only on information obtained from macular optical coherence tomography angiography (OCTA) images. We also propose an automatic methodology to rapidly measure the foveal avascular zone (FAZ) area and the vascular density (VD) in the superficial and deep capillary plexuses in swept-source OCTA images centered on the fovea. The proposed methodology is validated using a representative sample of 133 visits of 50 RVO patients. Our methodology estimates VA with very high precision and is even more accurate when we integrate depth information, providing a high correlation index of 0.869 with the real VA, which outperforms the correlation index of 0.855 obtained when estimating VA from the data obtained by the semiautomatic existing method. In conclusion, the proposed method is the first computational system able to estimate VA in RVO, with the additional benefits of being automatic, less time-consuming, objective and more accurate. Furthermore, the proposed method is able to integrate depth information, a feature which is lacking in the existing method.

scholarly journals In-Vivo Functional and Structural Retinal Imaging Using Multiwavelength Photoacoustic Remote Sensing Microscopy and Optical Coherence Tomography

2021 ◽  
Author(s):  
Zohreh Hosseinaee ◽  
Nicholas Pellegrino ◽  
Nima Abbasi ◽  
Tara Amiri ◽  
James A. Tummon Simmons ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Optical Coherence Tomography ◽  
Oxygen Saturation ◽  
Imaging Technique ◽  
Photoacoustic Imaging ◽  
Retinal Imaging ◽  
Optical Coherence ◽  
Swept Source ◽  
First Time

Abstract A multiwavelength photoacoustic remote sensing (PARS) microscope is combined with swept-source optical coherence tomography and applied to in-vivo, non-contact retinal imaging. Building on the proven strength of multiwavelength PARS imaging, the system is applied for estimating retinal oxygen saturation in the rat eye. The capability of the technology is demonstrated by imaging both microanatomy and the microvasculature of the retina in-vivo. To our knowledge, this is the first time a non-contact photoacoustic imaging technique is employed for in-vivo oxygen saturation measurement in the retina.

scholarly journals Laser Lens Size Measurement Using Swept-Source Optical Coherence Tomography

2020 ◽  
Vol 10 (14) ◽  
pp. 4936
Author(s):  
Pingping Jia ◽  
Hong Zhao ◽  
Yuwei Qin
Keyword(s):  
Optical Coherence Tomography ◽  
High Speed ◽  
Wave Number ◽  
Radius Of Curvature ◽  
Optical Coherence ◽  
Swept Source ◽  
Laser Focusing ◽  
Fitting Algorithm ◽  
Laser Confocal Microscope ◽  
Focusing Lens

A high-speed, high-resolution swept-source optical coherence tomography (SS-OCT) is presented for focusing lens imaging and a k-domain uniform algorithm is adopted to find the wave number phase equalization. The radius of curvature of the laser focusing lens was obtained using a curve-fitting algorithm. The experimental results demonstrate that the measuring accuracy of the proposed SS-OCT system is higher than the laser confocal microscope. The SS-OCT system has great potential for surface topography measurement and defect inspection of the focusing lens.

Impact of age, sex and refractive error on conjunctival and Tenon’s capsule thickness dimensions by swept-source optical coherence tomography in a large population

2021 ◽  
Author(s):  
José Ignacio Fernández-Vigo ◽  
Hang Shi ◽  
Bárbara Burgos-Blasco ◽  
Lucía De-Pablo-Gómez-de-Liaño ◽  
Ignacio Almorín-Fernández-Vigo ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Refractive Error ◽  
Large Population ◽  
Optical Coherence ◽  
Swept Source ◽  
Tenon’S Capsule ◽  
Tenon's Capsule ◽  
Capsule Thickness

scholarly journals Three-dimensional segmentation and depth-encoded visualization of choroidal vasculature using swept-source optical coherence tomography

2021 ◽  
pp. 153537022110285
Author(s):  
Hao Zhou ◽  
Tommaso Bacci ◽  
K Bailey Freund ◽  
Ruikang K Wang
Keyword(s):  
Optical Coherence Tomography ◽  
Three Dimensional ◽  
Age Related Macular Degeneration ◽  
Optical Coherence ◽  
Full Thickness ◽  
Swept Source ◽  
Automated Method ◽  
Choroidal Imaging ◽  
Choroidal Vasculature ◽  
Choroidal Vessels

The choroid provides nutritional support for the retinal pigment epithelium and photoreceptors. Choroidal dysfunction plays a major role in several of the most important causes of vision loss including age-related macular degeneration, myopic degeneration, and pachychoroid diseases such as central serous chorioretinopathy and polypoidal choroidal vasculopathy. We describe an imaging technique using depth-resolved swept-source optical coherence tomography (SS-OCT) that provides full-thickness three-dimensional (3D) visualization of choroidal anatomy including topographical features of individual vessels. Enrolled subjects with different clinical manifestations within the pachychoroid disease spectrum underwent 15 mm × 9 mm volume scans centered on the fovea. A fully automated method segmented the choroidal vessels using their hyporeflective lumens. Binarized choroidal vessels were rendered in a 3D viewer as a vascular network within a choroidal slab. The network of choroidal vessels was color depth-encoded with a reference to the Bruch’s membrane segmentation. Topographical features of the choroidal vasculature were characterized and compared with choroidal imaging obtained with indocyanine green angiography (ICGA) from the same subject. The en face SS-OCT projections of the larger choroid vessels closely resembled to that obtained with ICGA, with the automated SS-OCT approach proving additional depth-encoded 3D information. In 16 eyes with pachychoroid disease, the SS-OCT approach added clinically relevant structural details, including choroidal thickness and vessel depth, which the ICGA studies could not provide. Our technique appears to advance the in vivo visualization of the full-thickness choroid, successfully reveals the topographical features of choroidal vasculature, and shows potential for further quantitative analysis when compared with other choroidal imaging techniques. This improved visualization of choroidal vasculature and its 3D structure should provide an insight into choroid-related disease mechanisms as well as their responses to treatment.

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