1. Articles from Martin F. Kraus

    1-24 of 30 1 2 »
    1. Three Dimensional Enhanced Imaging of Vitreoretinal Interface in Diabetic Retinopathy Using Swept Source Optical Coherence Tomography

      Three Dimensional Enhanced Imaging of Vitreoretinal Interface in Diabetic Retinopathy Using Swept Source Optical Coherence Tomography

      Purpose To analyze the vitreoretinal interface in diabetic eyes using three-dimensional wide-field volumes acquired using high-speed, long-wavelength swept-source optical coherence tomography (SS-OCT). Design Prospective cross-sectional study. Methods Fifty-six diabetic patients (88 eyes) and 11 healthy non-diabetic controls (22 eyes) were recruited. Up to eight SS-OCT volumes were acquired for each eye. A registration algorithm removed motion artifacts and merged multiple SS-OCT volumes to improve signal. Vitreous visualization was enhanced using vitreous windowing method. Results Of 88 diabetic eyes, 20 eyes had no retinopathy, 21 eyes had non-proliferative diabetic retinopathy (NPDR) without macular edema, 20 eyes had proliferative diabetic retinopathy (PDR ...

      Read Full Article
    2. Characterization of Choroidal Layers in Normal Aging Eyes Using Enface Swept-Source Optical Coherence Tomography

      Characterization of Choroidal Layers in Normal Aging Eyes Using Enface Swept-Source Optical Coherence Tomography

      Purpose To characterize qualitative and quantitative features of the choroid in normal eyes using enface swept-source optical coherence tomography (SS-OCT). Methods Fifty-two eyes of 26 consecutive normal subjects were prospectively recruited to obtain multiple three-dimensional 12x12mm volumetric scans using a long-wavelength high-speed SS-OCT prototype. A motion-correction algorithm merged multiple SS-OCT volumes to improve signal. Retinal pigment epithelium (RPE) was segmented as the reference and enface images were extracted at varying depths every 4.13μm intervals. Systematic analysis of the choroid at different depths was performed to qualitatively assess the morphology of the choroid and quantify the absolute thicknesses as ...

      Read Full Article
    3. En Face Imaging of the Choroid in Polypoidal Choroidal Vasculopathy Using Swept-Source Optical Coherence Tomography

      En Face Imaging of the Choroid in Polypoidal Choroidal Vasculopathy Using Swept-Source Optical Coherence Tomography

      Objective To define morphological features of polypoidal choroidal vasculopathy (PCV) using en face images from swept source optical coherence tomography (SS-OCT). Design Prospective cross-sectional study. Methods Ten eyes from 6 patients with PCV and 10 eyes from 5 age-matched normal subjects. All subjects were prospectively scanned with a prototype SS-OCT system. A motion correction algorithm was applied to correct and merge scans into a single volumetric dataset. En face images were generated at intervals of 4.13 μm (1 pixel) relative to the Bruch's membrane. Results Age ± standard deviation for the PCV group was 62.4 (± 12.1) years ...

      Read Full Article
    4. Depth-encoded all-fiber swept source polarization sensitive OCT

      Depth-encoded all-fiber swept source polarization sensitive OCT

      Polarization sensitive optical coherence tomography (PS-OCT) is a functional extension of conventional OCT and can assess depth-resolved tissue birefringence in addition to intensity. Most existing PS-OCT systems are relatively complex and their clinical translation remains difficult. We present a simple and robust all-fiber PS-OCT system based on swept source technology and polarization depth-encoding. Polarization multiplexing was achieved using a polarization maintaining fiber. Polarization sensitive signals were detected using fiber based polarization beam splitters and polarization controllers were used to remove the polarization ambiguity. A simplified post-processing algorithm was proposed for speckle noise reduction relaxing the demand for phase stability. We ...

      Read Full Article
    5. Enhanced Vitreous Imaging in Healthy Eyes Using Swept Source Optical Coherence Tomography

      Enhanced Vitreous Imaging in Healthy Eyes Using Swept Source Optical Coherence Tomography

      Purpose To describe enhanced vitreous imaging for visualization of anatomic features and microstructures within the posterior vitreous and vitreoretinal interface in healthy eyes using swept-source optical coherence tomography (SS-OCT). The study hypothesis was that long-wavelength, high-speed, volumetric SS-OCT with software registration motion correction and vitreous window display or high-dynamic-range (HDR) display improves detection sensitivity of posterior vitreous and vitreoretinal features compared to standard OCT logarithmic scale display. Design Observational prospective cross-sectional study. Methods Multiple wide-field three-dimensional SS-OCT scans (500×500A-scans over 12×12 mm 2 ) were obtained using a prototype instrument in 22 eyes of 22 healthy volunteers. A registration ...

      Read Full Article
    6. Optical Coherence Tomography Angiography of Optic Disc Perfusion in Glaucoma

      Optical Coherence Tomography Angiography of Optic Disc Perfusion in Glaucoma

      Purpose To compare optic disc perfusion between normal subjects and subjects with glaucoma using optical coherence tomography (OCT) angiography and to detect optic disc perfusion changes in glaucoma. Design Observational, cross-sectional study. Participants Twenty-four normal subjects and 11 patients with glaucoma were included. Methods One eye of each subject was scanned by a high-speed 1050-nm–wavelength swept-source OCT instrument. The split-spectrum amplitude-decorrelation angiography (SSADA) algorithm was used to compute 3-dimensional optic disc angiography. A disc flow index was computed from 4 registered scans. Confocal scanning laser ophthalmoscopy (cSLO) was used to measure disc rim area, and stereo photography was used ...

      Read Full Article
    7. Choroidal Haller's and Sattler's Layer Thickness Measurement Using 3-Dimensional 1060-nm Optical Coherence Tomography

      Choroidal Haller's and Sattler's Layer Thickness Measurement Using 3-Dimensional 1060-nm Optical Coherence Tomography

      Objectives To examine the feasibility of automatically segmented choroidal vessels in three-dimensional (3D) 1060-nmOCT by testing repeatability in healthy and AMD eyes and by mapping Haller's and Sattler's layer thickness in healthy eyes Methods Fifty-five eyes (from 45 healthy subjects and 10 with non-neovascular age-related macular degeneration (AMD) subjects) were imaged by 3D-1060-nmOCT over a 36°x36° field of view. Haller's and Sattler's layer were automatically segmented, mapped and averaged across the Early Treatment Diabetic Retinopathy Study grid. For ten AMD eyes and ten healthy eyes, imaging was repeated within the same session and on another ...

      Read Full Article
    8. Feature Of The Week 4/2/14: A Compact High-Performance Hand-Held Device for Extending Ophthalmic OCT to New Points of Care (Narrated Presentation)

      Feature Of The Week 4/2/14: A Compact High-Performance Hand-Held Device for Extending Ophthalmic OCT to New Points of Care (Narrated Presentation)

      We developed an ultrahigh speed, handheld swept source optical coherence tomography (SS-OCT) ophthalmic instrument using a 2D MEMS mirror. A vertical cavity surface-emitting laser (VCSEL) operating at 1060 nm center wavelength yielded a 350 kHz axial scan rate and 10 µm axial resolution in tissue. The long coherence length of the VCSEL enabled a 3.08 mm imaging range with minimal sensitivity roll-off in tissue. Two different designs with identical optical components were tested to evaluate handheld OCT ergonomics. An iris camera aided in alignment of the OCT beam through the pupil and a manual fixation light selected the imaging ...

      Read Full Article
    9. Quantitative Optical Coherence Tomography Angiography of Choroidal Neovascularization in Age-related Macular Degeneration

      Quantitative Optical Coherence Tomography Angiography of Choroidal Neovascularization in Age-related Macular Degeneration

      Purpose To detect and quantify choroidal neovascularization (CNV) in patients with age-related macular degeneration (AMD) using optical coherence tomography (OCT) angiography. Design Observational, cross-sectional study. Participants A total of 5 normal subjects and 5 subjects with neovascular AMD were included. Methods A total of 5 eyes with neovascular AMD and 5 normal age-matched controls were scanned by a high-speed (100 000 A-scans/seconds) 1050-nm wavelength swept-source OCT. The macular angiography scan covered a 3×3-mm area and comprised 200×200×8 A-scans acquired in 3.5 seconds. Flow was detected using the split-spectrum amplitude-decorrelation angiography (SSADA) algorithm. Motion artifacts were ...

      Read Full Article
    10. Optical Coherence Tomography Angiography of Optic Disc Perfusion in Glaucoma

      Optical Coherence Tomography Angiography of Optic Disc Perfusion in Glaucoma

      Purpose To compare optic disc perfusion between normal subjects and subjects with glaucoma using optical coherence tomography (OCT) angiography and to detect optic disc perfusion changes in glaucoma. Design Observational, cross-sectional study. Participants Twenty-four normal subjects and 11 patients with glaucoma were included. Methods One eye of each subject was scanned by a high-speed 1050-nm–wavelength swept-source OCT instrument. The split-spectrum amplitude-decorrelation angiography (SSADA) algorithm was used to compute 3-dimensional optic disc angiography. A disc flow index was computed from 4 registered scans. Confocal scanning laser ophthalmoscopy (cSLO) was used to measure disc rim area, and stereo photography was used ...

      Read Full Article
    11. Ultrahigh speed endoscopic swept source optical coherence tomography using a VCSEL light source and micromotor catheter

      Ultrahigh speed endoscopic swept source optical coherence tomography using a VCSEL light source and micromotor catheter

      We developed an ultrahigh speed endoscopic swept source optical coherence tomography (OCT) system for clinical gastroenterology using a vertical-cavity surface-emitting laser (VCSEL) and micromotor based imaging catheter, which provided an imaging speed of 600 kHz axial scan rate and 8 μm axial resolution in tissue. The micromotor catheter was 3.2 mm in diameter and could be introduced through the 3.7 mm accessory port of an endoscope. Imaging was performed at 400 frames per second with an 8 μm spot size using a pullback to generate volumetric data over 16 mm with a pixel spacing of 5 μm in ...

      Read Full Article
    12. Feature Of The Week 2/16/14: En Face Enhanced-Depth Swept-Source Optical Coherence Tomography Features of Chronic Central Serous Chorioretinopath

      Feature Of The Week 2/16/14: En Face Enhanced-Depth Swept-Source Optical Coherence Tomography Features of Chronic Central Serous Chorioretinopath

      We characterized en face features of the retinal pigment epithelium (RPE) and choroid in eyes with chronic central serous chorioretinopathy (CSCR) using a high-speed, enhanced tissue penetration, swept-source optical coherence tomography (SS-OCT) prototype. Fifteen eyes of 13 consecutive patients with the clinical diagnosis of CSCR were prospectively examined with SS-OCT. Three-dimensional 6x6mm macular cube raster scans were obtained with SS-OCT operating at 1050nm wavelength and 100,000 A-lines/sec with 6µm axial resolution. Segmentation of the RPE generated a reference surface; en face SS-OCT images of the RPE and choroid were extracted at varying depths every 3.5 µm ...

      Read Full Article
    13. Handheld ultrahigh speed swept source optical coherence tomography instrument using a MEMS scanning mirror

      Handheld ultrahigh speed swept source optical coherence tomography instrument using a MEMS scanning mirror

      We developed an ultrahigh speed, handheld swept source optical coherence tomography (SS-OCT) ophthalmic instrument using a 2D MEMS mirror. A vertical cavity surface-emitting laser (VCSEL) operating at 1060 nm center wavelength yielded a 350 kHz axial scan rate and 10 µm axial resolution in tissue. The long coherence length of the VCSEL enabled a 3.08 mm imaging range with minimal sensitivity roll-off in tissue. Two different designs with identical optical components were tested to evaluate handheld OCT ergonomics. An iris camera aided in alignment of the OCT beam through the pupil and a manual fixation light selected the imaging ...

      Read Full Article
    14. In-Vivo Lamina Cribrosa Microarchitecture in Healthy and Glaucomatous Eyes as Assessed by Optical Coherence Tomography

      In-Vivo Lamina Cribrosa Microarchitecture in Healthy and Glaucomatous Eyes as Assessed by Optical Coherence Tomography

      Purpose: Lamina cribrosa (LC) is a leading location of glaucomatous damage. The purpose of this study is to compare LC 3-dimensional microarchitecture between healthy and glaucomatous eyes in-vivo using optical coherence tomography (OCT). Methods: Sixty-eight eyes (19 healthy and 49 glaucomatous) from 47 subjects were scanned in a 3.5x3.5x3.64mm volume (400x400x896 pixels) at the optic nerve head using swept-source OCT. The LC microarchitecture parameters were measured on the visible LC by an automated segmentation algorithm. The LC parameters were compared to diagnosis and visual field mean deviation (MD) using a linear mixed effects model accounting for age ...

      Read Full Article
    15. En Face Enhanced-Depth Swept-Source Optical Coherence Tomography Features of Chronic Central Serous Chorioretinopathy

      En Face Enhanced-Depth Swept-Source Optical Coherence Tomography Features of Chronic Central Serous Chorioretinopathy

      Objective To characterize en face features of the retinal pigment epithelium (RPE) and choroid in eyes with chronic central serous chorioretinopathy (CSCR) using a high-speed, enhanced-depth swept-source optical coherence tomography (SS-OCT) prototype. Design Consecutive patients with chronic CSCR were prospectively examined with SS-OCT. Participants Fifteen eyes of 13 patients. Methods Three-dimensional 6×6 mm macular cube raster scans were obtained with SS-OCT operating at 1050 nm wavelength and 100 000 A-lines/sec with 6 μm axial resolution. Segmentation of the RPE generated a reference surface; en face SS-OCT images of the RPE and choroid were extracted at varying depths every ...

      Read Full Article
    16. Automated lamina cribrosa microstructural segmentation in optical coherence tomography scans of healthy and glaucomatous eyes

      Automated lamina cribrosa microstructural segmentation in optical coherence tomography scans of healthy and glaucomatous eyes

      We demonstrate an automated segmentation method for in-vivo 3D optical coherence tomography (OCT) imaging of the lamina cribrosa (LC). Manual segmentations of coronal slices of the LC were used as a gold standard in parameter selection and evaluation of the automated technique. The method was validated using two prototype OCT devices; each had a subject cohort including both healthy and glaucomatous eyes. Automated segmentation of in-vivo 3D LC OCT microstructure performed comparably to manual segmentation and is useful for investigative research and in clinical quantification of the LC.

      Read Full Article
    17. Swept source optical coherence microscopy using a 1310 nm VCSEL light source

      Swept source optical coherence microscopy using a 1310 nm VCSEL light source

      We demonstrate high speed, swept source optical coherence microscopy (OCM) using a MEMS tunable vertical cavity surface-emitting laser (VCSEL) light source. The light source had a sweep rate of 280 kHz, providing a bidirectional axial scan rate of 560 kHz. The sweep bandwidth was 117 nm centered at 1310 nm, corresponding to an axial resolution of 13.1 µm in air, corresponding to 8.1 µm (9.6 µm spectrally shaped) in tissue. Dispersion mismatch from different objectives was compensated numerically, enabling magnification and field of view to be easily changed. OCM images were acquired with transverse resolutions between 0 ...

      Read Full Article
    18. Ultrahigh speed endoscopic optical coherence tomography using micromotor imaging catheter and VCSEL technology

      Ultrahigh speed endoscopic optical coherence tomography using micromotor imaging catheter and VCSEL technology

      We developed a micromotor based miniature catheter with an outer diameter of 3.2 mm for ultrahigh speed endoscopic swept source optical coherence tomography (OCT) using a vertical cavity surface-emitting laser (VCSEL) at a 1 MHz axial scan rate. The micromotor can rotate a micro-prism at several hundred frames per second with less than 5 V drive voltage to provide fast and stable scanning, which is not sensitive to the bending of the catheter. The side-viewing probe can be pulled back to acquire a three-dimensional (3D) data set covering a large area on the specimen. The VCSEL provides a high ...

      Read Full Article
    19. 4D dynamic imaging of the eye using ultrahigh speed SS-OCT

      4D dynamic imaging of the eye using ultrahigh speed SS-OCT

      Recent advances in swept-source / Fourier domain optical coherence tomography (SS-OCT) technology enable in vivo ultrahigh speed imaging, offering a promising technique for four-dimensional (4-D) imaging of the eye. Using an ultrahigh speed tunable vertical cavity surface emitting laser (VCSEL) light source based SS-OCT prototype system, we performed imaging of human eye dynamics in four different imaging modes: 1) Pupillary reaction to light at 200,000 axial scans per second and 9 μm resolution in tissue. 2) Anterior eye focusing dynamics at 100,000 axial scans per second and 9 μm resolution in tissue. 3) Tear film break up at 50 ...

      Read Full Article
    20. Ultrahigh speed endoscopic optical coherence tomography using micro-motor imaging catheter and VCSEL technology

      Ultrahigh speed endoscopic optical coherence tomography using micro-motor imaging catheter and VCSEL technology

      We developed a micro-motor based miniature catheter with an outer diameter of 3mm for ultrahigh speed endoscopic optical coherence tomography (OCT) using vertical cavity surface-emitting laser (VCSEL) at a 1MHz axial scan rate. The micro-motor can rotate a micro-prism at 1,200-72,000rpm (corresponding to 20- 1,200fps) with less than 5V driving voltage to provide fast and stable scanning, which is not sensitive to the bending of the catheter. The side-viewing probe can be pulled back for a long distance to acquire three-dimensional (3D) dataset covering a large area on the specimen. VCSEL provides high a-line rate to support ...

      Read Full Article
    21. In vivo imaging of the rodent eye with swept source/Fourier domain OCT

      In vivo imaging of the rodent eye with swept source/Fourier domain OCT

      Swept source/Fourier domain OCT is demonstrated for in vivo imaging of the rodent eye. Using commercial swept laser technology, we developed a prototype OCT imaging system for small animal ocular imaging operating in the 1050 nm wavelength range at an axial scan rate of 100 kHz with ~6 µm axial resolution. The high imaging speed enables volumetric imaging with high axial scan densities, measuring high flow velocities in vessels, and repeated volumetric imaging over time. The 1050 nm wavelength light provides increased penetration into tissue compared to standard commercial OCT systems at 850 nm. The long imaging range enables ...

      Read Full Article
    22. One-step Continuous Synthesis of Biocompatible Gold Nanorods for Optical Coherence Tomography

      One-step Continuous Synthesis of Biocompatible Gold Nanorods for Optical Coherence Tomography

      We present a one-step flow process to synthesize biocompatible gold nanorods with tunable absorption and bio-compatible surface ligands. Photothermal optical coherence tomography (OCT) of human breast tissue is demonstrated successfully using tailored gold nanorods designed to have strong absorption in the near infrared wavelength range.

      Read Full Article
    23. Motion correction in optical coherence tomography volumes on a per A-scan basis using orthogonal scan patterns

      Motion correction in optical coherence tomography volumes on a per A-scan basis using orthogonal scan patterns

      High speed Optical Coherence Tomography (OCT) has made it possible to rapidly capture densely sampled 3D volume data. One key application is the acquisition of high quality in vivo volumetric data sets of the human retina. Since the volume is acquired in a few seconds, eye movement during the scan process leads to distortion, which limits the accuracy of quantitative measurements using 3D OCT data. In this paper, we present a novel software based method to correct motion artifacts in OCT raster scans. Motion compensation is performed retrospectively using image registration algorithms on the OCT data sets themselves. Multiple, successively ...

      Read Full Article
    1-24 of 30 1 2 »
  1. Categories

    1. Applications:

      Art, Cardiology, Dentistry, Dermatology, Developmental Biology, Gastroenterology, Gynecology, Microscopy, NDE/NDT, Neurology, Oncology, Ophthalmology, Other Non-Medical, Otolaryngology, Pulmonology, Urology
    2. Business News:

      Acquisition, Clinical Trials, Funding, Other Business News, Partnership, Patents
    3. Technology:

      Broadband Sources, Probes, Tunable Sources
    4. Miscellaneous:

      Jobs & Studentships, Student Theses, Textbooks
  2. Topics in the News

    1. (30 articles) Massachusetts Institute of Technology
    2. (30 articles) James G. Fujimoto
    3. (29 articles) Martin F. Kraus
    4. (21 articles) University of Erlangen
    5. (20 articles) Jonathan J. Liu
    6. (17 articles) Benjamin M. Potsaid
    7. (15 articles) Thorlabs
    8. (13 articles) Tufts University
    9. (13 articles) Jay S. Duker
    10. (9 articles) Ireneusz Grulkowski
  3. Popular Articles

  4. Picture Gallery

    Retinal blood flow measurement with ultrahigh-speed swept-source / Fourier domain optical coherence tomography Piezoelectric transducer based miniature catheter for ultrahigh speed endoscopic optical coherence tomography Total retinal blood flow measurement with ultrahigh speed swept source/Fourier domain OCT Piezoelectric-transducer-based miniature catheter for ultrahigh-speed endoscopic optical coherence tomography Speckle reduction in swept source optical coherence tomography images with slow-axis averaging Split-spectrum amplitude-decorrelation angiography with optical coherence tomography Ultrahigh speed endoscopic optical coherence tomography using micro-motor imaging catheter and VCSEL technology Automated lamina cribrosa microstructural segmentation in optical coherence tomography scans of healthy and glaucomatous eyes Feature Of The Week 2/16/14: En Face Enhanced-Depth Swept-Source Optical Coherence Tomography Features of Chronic Central Serous Chorioretinopath Feature Of The Week 4/2/14: A Compact High-Performance Hand-Held Device for Extending Ophthalmic OCT to New Points of Care (Narrated Presentation) Measurement of the Shrinkage of Natural and Simulated Lesions on Root Surfaces using CP-OCT Optic-Net: A Novel Convolutional Neural Network for Diagnosis of Retinal Diseases from Optical Tomography Images