1. Articles from Joseph A. Izatt

    1-24 of 194 1 2 3 4 5 6 7 8 »
    1. Systems and methods for long working distance optical coherence tomography (OCT)

      Systems and methods for long working distance optical coherence tomography (OCT)

      Systems and methods for long working distance optical coherence tomography (OCT). According to an aspect, an OCT system includes a reference arm. Further, the OCT system includes a sample arm operably connected to the reference arm. The sample arm includes a scanner configured to scan an optical beam. The sample arm also includes an objective positioned a predetermined distance from the scanner, configured to receive the optical beam, and to direct the optical beam to an object positioned at about the predetermined distance from the scanner for imaging of the object.

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      Mentions: Duke University
    2. In Vivo Quantitative Analysis of Anterior Chamber White Blood Cell Mixture Composition Using Spectroscopic Optical Coherence Tomography

      In Vivo Quantitative Analysis of Anterior Chamber White Blood Cell Mixture Composition Using Spectroscopic Optical Coherence Tomography

      Anterior uveitis is the most common form of intraocular inflammation, and one of its main signs is the presence of white blood cells (WBCs) in the anterior chamber (AC). Clinically, the true composition of cells can currently only be obtained using AC paracentesis, an invasive procedure to obtain AC fluid requiring needle insertion into the AC. We previously developed a spectroscopic optical coherence tomography (SOCT) analysis method to differentiate between populations of RBCs and subtypes of WBCs, including granulocytes, lymphocytes and monocytes, both in vitro and in ACs of excised porcine eyes. We have shown that different types of WBCs ...

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      Mentions: Duke University
    3. Macular Optical Coherence Tomography Characteristics at 36 weeks Postmenstrual Age in Infants Examined for Retinopathy of Prematurity

      Macular Optical Coherence Tomography Characteristics at 36 weeks Postmenstrual Age in Infants Examined for Retinopathy of Prematurity

      Objective To report our ability to capture, grade reliably and analyze bedside macular optical coherence tomography (OCT) images from preterm infants and relate OCT findings to biological factors and retinopathy of prematurity (ROP) status at a single time window in the STudy of Eye imaging in Preterm infantS (BabySTEPS). Design Prospective observational study Participants Preterm infants eligible for ROP screening, with parental consent for research and a 36±1 weeks postmenstrual age (PMA) visit. Methods We imaged both eyes of preterm infants with an investigational non-contact, handheld swept-source OCT at the time of clinical ROP examinations. Macular OCT features and ...

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    4. Auto-Processed Retinal Vessel Shadow View Images From Bedside Optical Coherence Tomography to Evaluate Plus Disease in Retinopathy of Prematurity

      Auto-Processed Retinal Vessel Shadow View Images From Bedside Optical Coherence Tomography to Evaluate Plus Disease in Retinopathy of Prematurity

      Abstract Purpose : To describe the creation of en face retinal vessel shadow view (RVSV) optical coherence tomography (OCT) images and assess the feasibility of using these for evaluating vascular disease in preterm infants at risk for retinopathy of prematurity (ROP). Methods : In this exploratory study, we selected images from eyes with a range of ROP vascular disease, prospectively acquired from preterm infants using an investigational, noncontact, handheld, bedside swept-source OCT. We autosegmented OCT volumes using custom infant-specific software, extracted RVSV-OCT images from volumetric data bracketed around the retinal pigment epithelium, and automontaged the resulting RVSV-OCT images. Three masked ophthalmologists graded ...

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      Mentions: Duke University
    5. Lightweight Learning-based Automatic Segmentation of Subretinal Blebs on Microscope-Integrated Optical Coherence Tomography Images

      Lightweight Learning-based Automatic Segmentation of Subretinal Blebs on Microscope-Integrated Optical Coherence Tomography Images

      Purpose Subretinal injections of therapeutics are commonly used to treat ocular diseases. Accurate dosing of therapeutics at target locations is crucial but difficult to achieve using subretinal injections due to leakage, and there is no method available to measure the volume of therapeutics successfully administered to the subretinal location during surgery. Here we introduce the first automatic method for quantifying the volume of subretinal blebs, using porcine eyes injected with Ringer’s lactate solution as samples. Design Experimental study. Methods Microscope-integrated optical coherence tomography was utilized to obtain 3D visualization of subretinal blebs in porcine eyes at Duke Eye Center ...

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    6. Quantitative topographic curvature maps of the posterior eye utilizing optical coherence tomography

      Quantitative topographic curvature maps of the posterior eye utilizing optical coherence tomography

      Purpose: Deformations of the retina such as staphylomas in myopia or scleral flattening in high intracranial pressure can be challenging to quantify with en face imaging. We describe an OCT based method for the generation of quantitative posterior eye topography maps in normal and pathologic eyes. Methods: Utilizing “ whole eye ” OCT we corrected for subjects’ optical distortions to generate spatially accurate posterior eye OCT volumes and created local curvature ( K M , mm -1 ) topography maps for each consented subject. We imaged nine subjects, three normal, two with myopic degeneration (MD), and four with papilledema including one that was imaged longitudinally ...

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      Mentions: Duke University
    7. Systems and methods for eye tracking for motion corrected ophthalmic optical coherence tomography

      Systems and methods for eye tracking for motion corrected ophthalmic optical coherence tomography

      Systems and methods for eye tracking for motion corrected ophthalmic optical coherence tomography (OCT) are disclosed. According to an aspect, an imaging system includes an eye tracking device configured to determine movement of an eye. The imaging system also includes an OCT apparatus configured to generate OCT images of a retina of the eye. The OCT apparatus includes a scanner operable to be moved for relocating an OCT scan pivot at a pupil plane for image capture and during capture of the OCT images. The imaging system also includes a controller configured to control the scanner to relocate the OCT ...

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      Mentions: Duke University
    8. Spectroscopic optical coherence refraction tomography

      Spectroscopic optical coherence refraction tomography

      In optical coherence tomography (OCT), the axial resolution is often superior to the lateral resolution, which is sacrificed for long imaging depths. To address this anisotropy, we previously developed optical coherence refraction tomography (OCRT), which uses images from multiple angles to computationally reconstruct an image with isotropic resolution, given by the OCT axial resolution. On the other hand, spectroscopic OCT (SOCT), an extension of OCT, trades axial resolution for spectral resolution and hence often has superior lateral resolution. Here, we present spectroscopic OCRT (SOCRT), which uses SOCT images from multiple angles to reconstruct a spectroscopic image with isotropic spatial resolution ...

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      Mentions: Duke University
    9. Optical Coherence Tomography Guided Robotic Needle Insertion for Deep Anterior Lamellar Keratoplasty

      Optical Coherence Tomography Guided Robotic Needle Insertion for Deep Anterior Lamellar Keratoplasty

      Objective: Deep anterior lamellar keratoplasty (DALK) significantly reduces the post-transplantation morbidity in patients eligible for partial-thickness cornea grafts. The popular "big bubble" technique for DALK is so challenging, however, that a significant fraction of corneal pneumodissection attempts fail for surgeons without extensive DALK-specific experience, even with previous-generation cross-sectional optical coherence tomography (OCT) guidance. We seek to develop robotic, volumetric OCT-guided technology capable of facilitating or automating the difficult needle insertion step in DALK. Methods: Our system provides for real-time volumetric corneal imaging, segmentation, and tracking of the needle insertion to display feedback for surgeons and to generate needle insertion plans ...

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      Mentions: Duke University
    10. Optical coherence refraction tomography

      Optical coherence refraction tomography

      Optical coherence tomography (OCT) is a cross-sectional, micrometre-scale imaging modality with widespread clinical application. Typical OCT systems sacrifice lateral resolution to achieve long depths of focus for bulk tissue imaging, and therefore tend to have better axial than lateral resolution. Such anisotropic resolution can obscure fine ultrastructural features. Furthermore, conventional OCT suffers from refraction-induced image distortions. Here, we introduce optical coherence refraction tomography (OCRT), which extends the superior axial resolution to the lateral dimension, synthesizing undistorted cross-sectional image reconstructions from multiple conventional images acquired with angular diversity. In correcting refraction-induced distortions to register the OCT images, OCRT also achieves spatially ...

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      Mentions: Duke University
    11. Ocular anterior chamber blood cell population differentiation using spectroscopic optical coherence tomography

      Ocular anterior chamber blood cell population differentiation using spectroscopic optical coherence tomography

      There is potential clinical significance in identifying cellular responses in the anterior chamber (AC) of the eye, which can indicate hyphema (an accumulation of red blood cells [RBCs]) or aberrant intraocular inflammation (an accumulation of white blood cells [WBCs]). In this work, we developed a spectroscopic OCT analysis method to differentiate between populations of RBCs and subtypes of WBCs, including granulocytes, lymphocytes and monocytes, both in vitro and in ACs of porcine eyes. We developed an algorithm to track single cells within OCT data sets, and extracted the backscatter reflectance spectrum of each single cell from the detected interferograms using ...

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      Mentions: Duke University
    12. Advances in Whole-Eye Optical Coherence Tomography Imaging

      Advances in Whole-Eye Optical Coherence Tomography Imaging

      Contemporary anterior segment and retinal optical coherence tomography (OCT) systems only image their particular designated region of the eye and cannot image both areas of the eye at once. This separation is due to the differences in optical system design needed to properly image the front or back of the eye and also due to limitations in the imaging depth of current commercial OCT systems. More recently, research and commercial OCT systems capable of "whole-eye" imaging have been described. These whole-eye OCT systems enable applications such as ocular biometry for cataract surgery, ocular shape analysis for myopia, and others. Further ...

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      Mentions: Duke University
    13. Depth-Based, Motion-Stabilized Colorization of Microscope-Integrated Optical Coherence Tomography Volumes for Microscope-Independent Microsurgery

      Depth-Based, Motion-Stabilized Colorization of Microscope-Integrated Optical Coherence Tomography Volumes for Microscope-Independent Microsurgery

      Purpose : We develop and assess the impact of depth-based, motion-stabilized colorization (color) of microscope-integrated optical coherence tomography (MIOCT) volumes on microsurgical performance and ability to interpret surgical volumes. Methods : Color was applied in real-time as gradients indicating axial position and stabilized based on calculated center of mass. In a test comparing colorization versus grayscale visualizations of prerecorded intraoperative volumes from human surgery, ophthalmologists ( N = 7) were asked to identify retinal membranes, the presence of an instrument, its contact with tissue, and associated deformation of the retina. In a separate controlled trial, trainees ( N = 15) performed microsurgical skills without conventional optical ...

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      Mentions: Duke University
    14. Volumetric Measurement of Subretinal Blebs Using Microscope-Integrated Optical Coherence Tomography

      Volumetric Measurement of Subretinal Blebs Using Microscope-Integrated Optical Coherence Tomography

      Purpose : We advance studies of subretinal treatments by developing a microscope-integrated optical coherence tomography (MIOCT) image-based method for measuring the volume of therapeutics delivered into the subretinal space. Methods : A MIOCT image-based volume measurement method was developed and assessed for accuracy and reproducibility by imaging an object of known size in model eyes. This method then was applied to subretinal blebs created by injection of diluted triamcinolone. Bleb volumes obtained from MIOCT were compared to the intended injection volume and the surgeon's estimation of leakage. Results : Validation of the image-based volume measurement method showed accuracy to ±1.0 μL ...

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      Mentions: Duke University
    15. Imaging of Iris Lesions With High-Speed Optical Coherence Tomography

      Imaging of Iris Lesions With High-Speed Optical Coherence Tomography

      n BACKGROUND AND OBJECTIVES:To image and measure iris tumors with optical coherence tomography (OCT). n PATIENTS AND METHODS:High-speed(2,000– 4,000 axial-scan/sec and 4–16 frames/sec) 1.3-micron wavelength anterior segment OCT prototypes were used to image 6 eyes of 6 patients with a variety of iris lesions, including focal iris nevus, diffuse iris nevus, amelanotic iris nevus, iris melanocytosis, and iris melanoma. OCT images were compared with slit-lamp photography and ultrasound biomicroscopy. n RESULTS: OCT at 1.3-micron wavelength could penetrate the full thickness of the iris lesions and allow three-dimensional measurement of lesion ...

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    16. Statistical Models of Signal and Noise and Fundamental Limits of Segmentation Accuracy in Retinal Optical Coherence Tomography

      Statistical Models of Signal and Noise and Fundamental Limits of Segmentation Accuracy in Retinal Optical Coherence Tomography

      Optical coherence tomography (OCT) has revolutionized diagnosis and prognosis of ophthalmic diseases by visualization and measurement of retinal layers. To speed up quantitative analysis of disease biomarkers, an increasing number of automatic segmentation algorithms have been proposed to estimate the boundary locations of retinal layers. While the performance of these algorithms has significantly improved in recent years, a critical question to ask is how far we are from a theoretical limit to OCT segmentation performance. In this paper, we present the Cramèr-Rao lower bounds (CRLBs) for the problem of OCT layer segmentation. In deriving the CRLBs, we address the ...

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      Mentions: Duke University
    17. Characterization of Long Working Distance Optical Coherence Tomography for Imaging of Pediatric Retinal Pathology

      Characterization of Long Working Distance Optical Coherence Tomography for Imaging of Pediatric Retinal Pathology

      Purpose : We determined the feasibility of fovea and optic nerve head imaging with a long working distance (LWD) swept source optical coherence tomography (OCT) prototype in adults, teenagers, and young children. Methods : A prototype swept source OCT system with a LWD (defined as distance from the last optical element of the imaging system to the eye) of 350 mm with custom fixation targets was developed to facilitate imaging of children. Imaging was performed in 49 participants from three age groups: 26 adults, 16 children 13 to 18 years old (teenagers), and seven children under 6 years old (young children) under ...

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      Mentions: Duke University
    18. Retinal imaging in human autopsy eyes using a custom optical coherence tomography periscope

      Retinal imaging in human autopsy eyes using a custom optical coherence tomography periscope

      Age-related macular degeneration (AMD) is a major cause of vision loss in the elderly. To better study the pathobiology of AMD, postmortem eyes offer an excellent opportunity to correlate optical coherence tomography (OCT) imaging characteristics with histopathology. However, postmortem eyes from autopsy present challenges to standard OCT imaging including opaque anterior segment structures and standard of care autopsy processing resulting in oblique views to the macula. To overcome these challenges, we report a custom periscope attached by a standard mount to an OCT sample arm and demonstrate high quality macular OCT acquisitions in autopsy-processed eyes.

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      Mentions: Duke University
    19. Introduction to the feature issue on the 25 year anniversary of optical coherence tomography

      Introduction to the feature issue on the 25 year anniversary of optical coherence tomography

      This feature issue commemorates the approximately 25 year history of Optical Coherence Tomography (OCT), one of the most successful biophotonic technologies. While OCT has technological origins traceable to ultrafast laser development and fiber optic system test instrumentation of the 1980’s, innovations in low coherence interferometry for optical ranging and imaging for biomedical applications in the U.S., Europe and Japan by the early 1990’s led to coinage of the now widely known term OCT in 1991 [1]. As discussed in the following cited Invited Review and Invited Research articles in this issue, remarkable strides have since been made ...

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    20. Microscope-Integrated Optical Coherence Tomography Angiography in the Operating Room in Young Children With Retinal Vascular Disease

      Microscope-Integrated Optical Coherence Tomography Angiography in the Operating Room in Young Children With Retinal Vascular Disease

      Importance Intraoperative optical coherence tomography (OCT) has gained traction as an important adjunct for clinical decision making during vitreoretinal surgery, and OCT angiography (OCTA) has provided novel insights in clinical evaluation of retinal diseases. To date, these two technologies have not been applied in combination to evaluate retinal vascular disease in the operating suite. Objective To conduct microscope-integrated, swept-source OCTA (MIOCTA) in children with retinal vascular disease. Design, Setting, and Participants In this case report analysis, OCT imaging in pediatric patients, MIOCTA images were obtained during examination under anesthesia from a young boy with a history of idiopathic vitreous hemorrhage ...

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      Mentions: Duke University
    21. Review of intraoperative optical coherence tomography: technology and applications [Invited]

      Review of intraoperative optical coherence tomography: technology and applications [Invited]

      During microsurgery, en face imaging of the surgical field through the operating microscope limits the surgeon’s depth perception and visualization of instruments and sub-surface anatomy. Surgical procedures outside microsurgery, such as breast tumor resections, may also benefit from visualization of the sub-surface tissue structures. The widespread clinical adoption of optical coherence tomography (OCT) in ophthalmology and its growing prominence in other fields, such as cancer imaging, has motivated the development of intraoperative OCT for real-time tomographic visualization of surgical interventions. This article reviews key technological developments in intraoperative OCT and their applications in human surgery. We focus on handheld ...

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      Mentions: Duke University
    22. Four-dimensional Microscope-Integrated Optical Coherence Tomography to Visualize Suture Depth in Strabismus Surgery

      Four-dimensional Microscope-Integrated Optical Coherence Tomography to Visualize Suture Depth in Strabismus Surgery

      The authors report the use of swept-source microscope-integrated optical coherence tomography (SS-MIOCT), capable of live four-dimensional (three-dimensional across time) intraoperative imaging, to directly visualize suture depth during lateral rectus resection. Key surgical steps visualized in this report included needle depth during partial and full-thickness muscle passes along with scleral passes.

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      Mentions: Duke University
    1-24 of 194 1 2 3 4 5 6 7 8 »
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