1. Articles from Anthony N. Kuo

    1-24 of 36 1 2 »
    1. 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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    2. 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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    3. Topography and pachymetry maps for mouse corneas using optical coherence tomography

      Topography and pachymetry maps for mouse corneas using optical coherence tomography

      The majority of the eye's refractive power lies in the cornea, and pathological changes in its shape can affect vision. Small animal models offer an unparalleled degree of control over genetic and environmental factors that can help elucidate mechanisms of diseases affecting corneal shape. However, there is not currently a method to characterize the corneal shape of small animal eyes with topography or pachymetry maps, as is done clinically for humans. We bridge this gap by demonstrating methods using optical coherence tomography (OCT) to generate the first topography and pachymetry (thickness) maps of mouse corneas. Radii of curvature acquired ...

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    4. 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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    5. 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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    6. 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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    7. Anterior chamber blood cell differentiation using spectroscopic optical coherence tomography

      Anterior chamber blood cell differentiation using spectroscopic optical coherence tomography

      There is great clinical importance in identifying cellular responses in the anterior chamber (AC) which can indicate signs of hyphema (an accumulation of red blood cells (RBCs)) or aberrant intraocular inflammation (an accumulation of white blood cells (WBCs)). These responses are difficult to diagnose and require specialized equipment such as ophthalmic microscopes and specialists trained in examining the eye. In this work, we applied spectroscopic OCT to differentiate between RBCs and subtypes of WBCs, including neutrophils, lymphocytes and monocytes, both in vitro and in ACs of porcine eyes. We located and tracked single cells in OCT volumetric images, and extracted ...

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    8. 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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    9. 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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    10. 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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    11. Wireless, Web-Based Interactive Control of Optical Coherence Tomography with Mobile Devices

      Wireless, Web-Based Interactive Control of Optical Coherence Tomography with Mobile Devices

      Purpose : Optical coherence tomography (OCT) is widely used in ophthalmology clinics and has potential for more general medical settings and remote diagnostics. In anticipation of remote applications, we developed wireless interactive control of an OCT system using mobile devices. Methods : A web-based user interface (WebUI) was developed to interact with a handheld OCT system. The WebUI consisted of key OCT displays and controls ported to a webpage using HTML and JavaScript. Client–server relationships were created between the WebUI and the OCT system computer. The WebUI was accessed on a cellular phone mounted to the handheld OCT probe to wirelessly ...

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    12. Segmentation guided registration of wide field-of-view retinal optical coherence tomography volumes

      Segmentation guided registration of wide field-of-view retinal optical coherence tomography volumes

      Patient motion artifacts are often visible in densely sampled or large wide field-of-view (FOV) retinal optical coherence tomography (OCT) volumes. A popular strategy for reducing motion artifacts is to capture two orthogonally oriented volumetric scans. However, due to larger volume sizes, longer acquisition times, and corresponding larger motion artifacts, the registration of wide FOV scans remains a challenging problem. In particular, gaps in data acquisition due to eye motion, such as saccades, can be significant and their modeling becomes critical for successful registration. In this article, we develop a complete computational pipeline for the automatic motion correction and accurate registration ...

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    13. Needle Depth and Big-Bubble Success in Deep Anterior Lamellar Keratoplasty: An Ex Vivo Microscope-Integrated OCT Study

      Needle Depth and Big-Bubble Success in Deep Anterior Lamellar Keratoplasty: An Ex Vivo Microscope-Integrated OCT Study

      Purpose: To examine big-bubble (BB) formation success rates in deep anterior lamellar keratoplasty (DALK) at various corneal depths using real-time guidance from swept-source, microscope-integrated optical coherence tomography (SS-MIOCT). Methods: The DALK procedure was performed ex vivo with 34 human donor corneoscleral buttons on pressurized artificial anterior chambers using the BB technique employed by Anwar and Teichmann. We inserted a needle under controlled ex vivo conditions to corneal depths ranging from 40% to ≥90% using real-time guidance from SS-MIOCT and injected air. BB success was then determined for each injection. Results: The average needle depth for successful full BB formation was ...

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    14. Method for single illumination source combined optical coherence tomography and fluorescence imaging of fluorescently labeled ocular structures in transgenic mice

      Method for single illumination source combined optical coherence tomography and fluorescence imaging of fluorescently labeled ocular structures in transgenic mice

      In vivo imaging permits longitudinal study of ocular disease processes in the same animal over time. Two different in vivo optical imaging modalities – optical coherence tomography (OCT) and fluorescence – provide important structural and cellular data respectively about disease processes. In this Methods in Eye Research article, we describe and demonstrate the combination of these two modalities producing a truly simultaneous OCT and fluorescence imaging system for imaging of fluorescently labeled animal models. This system uses only a single light source to illuminate both modalities, and both share the same field of view. This allows simultaneous acquisition of OCT and fluorescence ...

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    15. Impact of Microscope-Integrated OCT on Ophthalmology Resident Performance of Anterior Segment Surgical Maneuvers in Model Eyes

      Impact of Microscope-Integrated OCT on Ophthalmology Resident Performance of Anterior Segment Surgical Maneuvers in Model Eyes

      Purpose : The integration of swept-source optical coherence tomography (SS-OCT) into the operating microscope enables real-time, tissue-level three-dimensional (3D) imaging to aid in ophthalmic microsurgery. In this prospective randomized controlled study, we evaluated the impact of SS microscope-integrated OCT (MI-OCT) on ophthalmology residents' performance of ophthalmic microsurgical maneuvers. Methods : Fourteen ophthalmology residents from a single institution were stratified by year of training and randomized to perform four anterior segment surgical maneuvers on porcine eyes with (MI-OCT+) or without (MI-OCT−) direct intraoperative OCT guidance. Subsequently, both groups repeated the same maneuvers without MI-OCT feedback to test whether initial MI-OCT experience affected subsequent ...

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    16. Posterior Eye Shape Measurement With Retinal OCT Compared to MRI

      Posterior Eye Shape Measurement With Retinal OCT Compared to MRI

      Purpose : Posterior eye shape assessment by magnetic resonance imaging (MRI) is used to study myopia. We tested the hypothesis that optical coherence tomography (OCT), as an alternative, could measure posterior eye shape similarly to MRI. Methods : Macular spectral-domain OCT and brain MRI images previously acquired as part of the Singapore Epidemiology of Eye Diseases study were analyzed. The right eye in the MRI and OCT images was automatically segmented. Optical coherence tomography segmentations were corrected for optical and display distortions requiring biometry data. The segmentations were fitted to spheres and ellipsoids to obtain the posterior eye radius of curvature ( R ...

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    17. Methods and computer program products for quantitative three-dimensional image correction and clinical parameter computation in optical coherence tomography

      Methods and computer program products for quantitative three-dimensional image correction and clinical parameter computation in optical coherence tomography

      Methods and computer program products for quantitative three-dimensional ("3D") image correction in optical coherence tomography. Using the methods and computer program products, index interface (refracting) surfaces from the raw optical coherence tomography ("OCT") dataset from an OCT system can be segmented. Normal vectors or partial derivatives of the curvature at a refracting surface can be calculated to obtain a refracted image voxel. A new position of each desired refracted image voxel can be iteratively computed. New refracted corrected voxel positions to an even sampling grid can be interpolated to provide corrected image data. In some embodiments, clinical outputs from the ...

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    18. Novel microscope-integrated stereoscopic heads-up display for intrasurgical optical coherence tomography

      Novel microscope-integrated stereoscopic heads-up display for intrasurgical optical coherence tomography

      Intra-operative optical coherence tomography (OCT) requires a display technology which allows surgeons to visualize OCT data without disrupting surgery. Previous research and commercial intrasurgical OCT systems have integrated heads-up display (HUD) systems into surgical microscopes to provide monoscopic viewing of OCT data through one microscope ocular. To take full advantage of our previously reported real-time volumetric microscope-integrated OCT (4D MIOCT) system, we describe a stereoscopic HUD which projects a stereo pair of OCT volume renderings into both oculars simultaneously. The stereoscopic HUD uses a novel optical design employing spatial multiplexing to project dual OCT volume renderings utilizing a single micro-display ...

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    19. Wide field of view swept-source optical coherence tomography for peripheral retinal disease

      Wide field of view swept-source optical coherence tomography for peripheral retinal disease

      Background/aims To assess peripheral retinal lesions and the posterior pole in single widefield optical coherence tomography (OCT) volumes. Methods A wide field of view (FOV) swept-source OCT (WFOV SSOCT) system was developed using a commercial swept-source laser and a custom sample arm consisting of two indirect ophthalmic lenses. Twenty-seven subjects with peripheral lesions (choroidal melanomas, choroidal naevi, sclerochoroidal calcification, retinitis pigmentosa, diabetic retinopathy, retinoschisis and uveitis) were imaged with the WFOV SSOCT. Volumes were taken in primary gaze. Using the optic nerve to fovea distance as a reference measurement, comparisons were made between the lateral FOV of the WFOV ...

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    20. Handheld, rapidly switchable, anterior/posterior segment swept source optical coherence tomography probe

      Handheld, rapidly switchable, anterior/posterior segment swept source optical coherence tomography probe

      We describe the first handheld, swept source optical coherence tomography (SSOCT) system capable of imaging both the anterior and posterior segments of the eye in rapid succession. A single 2D microelectromechanical systems (MEMS) scanner was utilized for both imaging modes, and the optical paths for each imaging mode were optimized for their respective application using a combination of commercial and custom optics. The system has a working distance of 26.1 mm and a measured axial resolution of 8 μm (in air). In posterior segment mode, the design has a lateral resolution of 9 μm, 7.4 mm imaging depth ...

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    21. Complete 360° circumferential gonioscopic optical coherence tomography imaging of the iridocorneal angle

      Complete 360° circumferential gonioscopic optical coherence tomography imaging of the iridocorneal angle

      Clinically, gonioscopy is used to provide en face views of the ocular angle. The angle has been imaged with optical coherence tomography (OCT) through the corneoscleral limbus but is currently unable to image the angle from within the ocular anterior chamber. We developed a novel gonioscopic OCT system that images the angle circumferentially from inside the eye through a custom, radially symmetric, gonioscopic contact lens. We present, to our knowledge, the first 360° circumferential volumes (two normal subjects, two subjects with pathology) of peripheral iris and iridocorneal angle structures obtained via an internal approach not typically available in the clinic.

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    22. Optical Coherence Tomography Accurately Measures Corneal Power Change from Laser Refractive Surgery

      Optical Coherence Tomography Accurately Measures Corneal Power Change from Laser Refractive Surgery

      Purpose To determine the ability of motion-corrected optical coherence tomography (OCT) to measure the corneal refractive power change due to LASIK. Design Evaluation of a diagnostic test or technology in a cohort. Subjects A total of 70 eyes from 37 subjects undergoing LASIK were measured preoperatively. A total of 39 eyes from 22 subjects were measured postoperatively and completed the study. Methods Consecutive patients undergoing LASIK at the Duke Eye Center who consented to participate were imaged with Placido-ring topography, Scheimpflug photography, and OCT on the day of their surgery. Patients were then reimaged with the same imaging systems at ...

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    1-24 of 36 1 2 »
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  2. Topics in the News

    1. (36 articles) Duke University
    2. (36 articles) Anthony N. Kuo
    3. (34 articles) Joseph A. Izatt
    4. (11 articles) Sina Farsiu
    5. (10 articles) Cynthia A. Toth
    6. (8 articles) Oscar Carrasco-Zevallos
    7. (5 articles) Mingtao Zhao
    8. (2 articles) Stephanie J. Chiu
    9. (2 articles) Zhejiang University
    10. (2 articles) Raju Poddar
    11. (1 articles) Georgia Institute of Technology
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    13. (1 articles) Duke University
    14. (1 articles) Anthony N. Kuo
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    16. (1 articles) Jon Holmes
    17. (1 articles) Michelson Diagnostics
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    3D refraction correction and extraction of clinical parameters from spectral domain optical coherence tomography of the cornea Methods And Computer Program Products For Quantitative Three-Dimensional Image Correction And Clinical Parameter Computation In Optical Coherence Tomography Robust automatic segmentation of corneal layer boundaries in SDOCT images using graph theory and dynamic programming Corneal biometry from volumetric SDOCT and comparison with existing clinical modalities Distributed scanning volumetric SDOCT for motion corrected corneal biometry Correction of Ocular Shape in Retinal Optical Coherence Tomography and Effect on Current Clinical Measures Fast Acquisition and Reconstruction of Optical Coherence Tomography Images via Sparse Representation Expanding OCT: Quanitifying the Cornea’s Optical Performance Handheld, rapidly switchable, anterior/posterior segment swept source optical coherence tomography probe Novel microscope-integrated stereoscopic heads-up display for intrasurgical optical coherence tomography High performance OCTA enabled by combining features of shape, intensity, and complex decorrelation A Novel 3D Segmentation Approach for Extracting Retinal Layers from Optical Coherence Tomography Images