1. Articles from Joseph Carroll

    1-24 of 42 1 2 »
    1. Optical Coherence Tomography Artifacts Are Associated With Adaptive Optics Scanning Light Ophthalmoscopy Success in Achromatopsia

      Optical Coherence Tomography Artifacts Are Associated With Adaptive Optics Scanning Light Ophthalmoscopy Success in Achromatopsia

      Purpose : To determine whether artifacts in optical coherence tomography (OCT) images are associated with the success or failure of adaptive optics scanning light ophthalmoscopy (AOSLO) imaging in subjects with achromatopsia (ACHM). Methods : Previously acquired OCT and non-confocal, split-detector AOSLO images from one eye of 66 subjects with genetically confirmed achromatopsia (15 CNGA3 and 51 CNGB3 ) were reviewed along with best-corrected visual acuity (BCVA) and axial length. OCT artifacts in interpolated vertical volumes from CIRRUS macular cubes were divided into four categories: (1) none or minimal, (2) clear and low frequency, (3) low amplitude and high frequency, and (4) high amplitude ...

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    2. Assessing the Influence of OCT-A Device and Scan Size on Retinal Vascular Metrics

      Assessing the Influence of OCT-A Device and Scan Size on Retinal Vascular Metrics

      Purpose : The purpose of this study was to investigate the effect of device and scan size on quantitative optical coherence tomography angiography (OCT-A) metrics. Methods : The 3 × 3 mm scans from Optovue AngioVue and Zeiss AngioPlex systems were included for 18 eyes of 18 subjects without ocular pathology. The foveal avascular zone (FAZ) was segmented manually by two observers, from which estimates of FAZ area (using both the nominal image scale and the axial length corrected image scale) and acircularity were derived. Three scan sizes (3 mm, 6 mm HD, and 8 mm) from the AngioVue system were included for ...

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    3. Imaging of Macrophage-Like Cells in Living Human Retina Using Clinical OCT

      Imaging of Macrophage-Like Cells in Living Human Retina Using Clinical OCT

      Purpose : To image retinal macrophages at the vitreoretinal interface in the living human retina using a clinical optical coherence tomography (OCT) device. Methods : Eighteen healthy controls and three patients with retinopathies were imaged using a clinical spectral-domain OCT. In controls, 10 sequential scans were collected at three different locations: (1) ∼9 degrees temporal to the fovea, (2) the macula, and (3) the optic nerve head (ONH). Intervisit repeatability was evaluated by imaging the temporal retina twice on the same day and 3 days later. Only 10 scans at the temporal retina were obtained from each patient. A 3-µm OCT ...

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    4. Assessing the Use of Incorrectly Scaled Optical Coherence Tomography Angiography Images in Peer-Reviewed Studies

      Assessing the Use of Incorrectly Scaled Optical Coherence Tomography Angiography Images in Peer-Reviewed Studies

      Importance Individual differences in axial length affect the lateral magnification of in vivo retinal images and as a result can affect the accuracy of quantitative measurements made from these images. As measurements from optical coherence tomography angiography (OCTA) images are becoming increasingly used in the diagnosis and monitoring of a wide range of diseases, evaluating which studies use correctly scaled images is crucial to their interpretation. Objective To perform a systematic literature review to assess the percentage of articles that report correcting the scale of their OCTA images for individual differences in retinal magnification. Evidence Review A PubMed (MEDLINE) search ...

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    5. Assessing Retinal Structure in Patients with Parkinson Disease

      Assessing Retinal Structure in Patients with Parkinson Disease

      Objective : The retina is an extension of the central nervous system (CNS), and ocular symptoms can precede manifestations of CNS disorders. Given that several neurodegenerative conditions that affect the brain exhibit ocular symptoms, the retina may be an accessible biomarker to monitor disease progression. Dopamine, the key neurotransmitter related to Parkinson’s disease (PD), is contained in amacrine and interplexiform cells, which reside in specific retinal layers. Understanding how loss of dopaminergic cells affects retinal anatomy could be relevant for monitoring disease progression. Here, our objective is to evaluate retinal structure (foveal pit morphology and thickness) in patients with PD ...

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    6. Earliest Evidence of Preclinical Diabetic Retinopathy Revealed using OCT Angiography (OCTA) Perfused Capillary Density

      Earliest Evidence of Preclinical Diabetic Retinopathy Revealed using OCT Angiography (OCTA) Perfused Capillary Density

      Purpose To compare perfused capillary density (PCD) in diabetic patients and healthy controls using optical coherence tomography angiography (OCTA). Methods Forty controls, 36 diabetics without clinical retinopathy (NoDR), 38 with nonproliferative retinopathy (NPDR), and 38 with proliferative retinopathy (PDR) were imaged using SD-OCT. A 3x3 mm full-thickness parafoveal OCTA scan was obtained from each participant. Following manual delineation of the foveal avascular zone (FAZ), FAZ area, perimeter, and acircularity index were determined. Seven consecutive equidistant 200-μm-wide annular segments were drawn at increasing eccentricities from the FAZ margin. Annular PCD (%) was defined as perfused capillary area divided by the corresponding ...

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    7. Variability of Foveal Avascular Zone Metrics Derived From Optical Coherence Tomography Angiography Images

      Variability of Foveal Avascular Zone Metrics Derived From Optical Coherence Tomography Angiography Images

      Purpose : To characterize sources of inter- and intrasubject variability in quantitative foveal avascular zone (FAZ) metrics. Methods : Two 3×3-mm optical coherence tomography angiography scans (centered on the fovea) were acquired in both eyes of 175 subjects. An image of the superficial plexus was extracted from each scan and segmented twice by a single observer. Four quantitative FAZ morphology metrics (area, axis ratio, acircularity, major horizontal axis angle) were calculated, and a variance components analysis was performed. Results : Mean (±SD) age was 27.9 ± 11.9 years, and 55% were female. Area had the largest amount of variance resulting from ...

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    8. Imaging Melanin Distribution in the Zebrafish Retina Using Photothermal Optical Coherence Tomography

      Imaging Melanin Distribution in the Zebrafish Retina Using Photothermal Optical Coherence Tomography

      Purpose : To demonstrate and validate that photothermal optical coherence tomography (PT-OCT) can image melanin in the retinal pigment epithelium (RPE) and can observe light-driven melanosome translocation in the zebrafish retina. Methods : A commercial spectral domain OCT system was modified to perform both OCT and PT-OCT. Four adult tyrosinase-mosaic zebrafish with varying levels of melanin expression across their retinas were imaged, and the PT-OCT signal for pigmented and nonpigmented regions were compared. Wild-type dark-adapted ( n = 11 fish) and light-adapted ( n = 10 fish) zebrafish were also imaged with OCT and PT-OCT. Longitudinal reflectivity and absorption profiles were generated from B-scans to compare ...

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    9. Parafoveal Nonperfusion Analysis in Diabetic Retinopathy Using Optical Coherence Tomography Angiography

      Parafoveal Nonperfusion Analysis in Diabetic Retinopathy Using Optical Coherence Tomography Angiography

      Purpose : To describe a new technique for mapping parafoveal intercapillary areas (PICAs) using optical coherence tomography angiography (OCTA), and demonstrate its utility for quantifying parafoveal nonperfusion in diabetic retinopathy (DR). Methods : Nineteen controls, 15 diabetics with no retinopathy (noDR), 15 with nonproliferative diabetic retinopathy (NPDR), and 15 with proliferative diabetic retinopathy (PDR) were imaged with 10 macular OCTA scans. PICAs were automatically delineated on the averaged superficial OCTA images. Following creation of an eccentricity-specific reference database from the controls, all PICAs greater than 2 SD above the reference means for PICA area and minor axis length were identified as nonperfused ...

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    10. Axial Scaling Is Independent of Ocular Magnification in OCT Images

      Axial Scaling Is Independent of Ocular Magnification in OCT Images

      We read with great interest the article by Röck et al., 1 as it is a well-known physical principle of optical coherence tomography (OCT) and its basis, low-coherence interferometry, that magnification of the image of the sample using an objective lens or eyes with varying refractive power applies only in the transverse dimension, 2 not the axial dimension. 3 In this article, the authors collected OCT scans of a subretinal implant of known thickness, but found a significant correlation between observed thickness of the implant and the subjects' axial length. Regrettably, the authors made no mention of the surprising ...

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      Mentions: Joseph Carroll
    11. Photothermal optical coherence tomography of indocyanine green in ex vivo eyes

      Photothermal optical coherence tomography of indocyanine green in ex vivo eyes

      Indocyanine green (ICG) is routinely used during surgery to stain the inner limiting membrane (ILM) and provide contrast on white light surgical microscopy. While translation of optical coherence tomography (OCT) for intraoperative imaging during ophthalmic surgery has enhanced visualization, the ILM remains difficult to distinguish from underlying retinal structures and ICG does not provide additional OCT contrast. We present photothermal OCT (PT-OCT) for high-specificity detection of ICG on retinal OCT images. We demonstrate our technique by performing an ILM peel in ex vivo eyes using low ICG concentrations and laser powers. These results establish the feasibility of PT-OCT for intraoperative ...

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    12. Repeatability and Reproducibility of In Vivo Cone Density Measurements in the Adult Zebrafish Retina

      Repeatability and Reproducibility of In Vivo Cone Density Measurements in the Adult Zebrafish Retina

      Zebrafish ( Danio rerio ) are widely used as an experimental model for a wide range of retinal diseases. Previously, optical coherence tomography (OCT) was introduced for quantitative analysis of the zebrafish cone photoreceptor cell mosaic; however no data exists on the intersession reproducibility or intrasession repeatability of such measurements. We imaged 14 wild-type (WT) fish three times each, with 48 h between each time point. En face images of the UV cone mosaic were generated from the OCT volume scans at each time point. These images were then aligned and the overlapping area cropped for analysis. Using a semiautomated cone-counting algorithm ...

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    13. INTRAOPERATIVE IMAGING OF RETAINED PERFLUOROCARBON LIQUID USING SPECTRAL DOMAIN OPTICAL COHERENCE TOMOGRAPHY

      INTRAOPERATIVE IMAGING OF RETAINED PERFLUOROCARBON LIQUID USING SPECTRAL DOMAIN OPTICAL COHERENCE TOMOGRAPHY

      Purpose: To report images of retained perfluorocarbon liquid (PFCL) on the surface of the retina obtained during an intraoperative use of hand-held spectral domain optical coherence tomography. Methods: A 54-year-old man underwent pars plana vitrectomy with injection of PFCL to repair retinal detachment. Postoperatively, visually significant PFCL droplets were found to be retained in the eye. During the surgical removal of PFCL, a hand-held spectral domain optical coherence tomography was used to image the retina with the patient supine. Results: Spectral domain optical coherence tomography images of the retained PFCL illustrated magnification of the areas of the outer retina underlying ...

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    14. Assessing the Accuracy of Foveal Avascular Zone Measurements Using Optical Coherence Tomography Angiography: Segmentation and Scaling

      Assessing the Accuracy of Foveal Avascular Zone Measurements Using Optical Coherence Tomography Angiography: Segmentation and Scaling

      Purpose : The foveal avascular zone (FAZ) is altered in numerous diseases. We assessed factors (axial length, segmentation method, age, sex) impacting FAZ measurements from optical coherence tomography (OCT) angiography images. Methods : We recruited 116 Caucasian subjects without ocular disease, and acquired two 3 × 3 mm AngioVue scans per each right eye (232 total scans). In images of the superficial plexus, the FAZ was segmented using the AngioVue semiautomatic nonflow measurement tool and ImageJ manual segmentation. In images from the full retinal thickness, the FAZ was segmented using the AngioAnalytics automatic FAZ tool. Repeatability, reliability, and reproducibility were calculated for FAZ ...

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    15. Quantitative Analysis of Retinal Structure Using Spectral-Domain Optical Coherence Tomography in RPGR-Associated Retinopathy

      Quantitative Analysis of Retinal Structure Using Spectral-Domain Optical Coherence Tomography in RPGR-Associated Retinopathy

      Purpose To quantify retinal structure and progression using spectral-domain optical coherence tomography (SDOCT) in patients with retinitis pigmentosa (RP) associated with retinitis pigmentosa GTPase regulator gene ( RPGR ) mutations. Design Retrospective observational case series. Methods Setting : Moorfields Eye Hospital, London, United Kingdom. Subjects : Both eyes of 32 patients. SDOCT follow-up period of >1 year (3.1 ± 1.4 years). Main Outcome Measures : Ellipsoid zone (EZ) width (EZW) and outer nuclear layer (ONL) and inner retinal layer (IRL) thickness measurements. Progression rates, interocular symmetry, and association with age and genotype were investigated. Results Significant differences were observed between baseline and final measurements ...

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      Mentions: Joseph Carroll
    16. The Effect of Retinal Melanin on Optical Coherence Tomography Images

      The Effect of Retinal Melanin on Optical Coherence Tomography Images

      Purpose : We assessed the effect of melanin on the appearance of hyperreflective outer retinal bands in optical coherence tomography (OCT) images. Methods : A total of 23 normal subjects and 51 patients with albinism were imaged using the Bioptigen high-resolution spectral-domain OCT. In addition, three wild type, three albino ( slc45a2 b4/b4 ), and eight tyrosinase mosaic zebrafish were imaged with the hand-held Bioptigen Envisu R2200 OCT. To identify pigmented versus nonpigmented regions in the tyrosinase mosaic zebrafish, en face summed volume projections of the retinal pigment epithelium (RPE) were created from volume scans. Longitudinal reflectivity profiles were generated from B-scans to ...

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    17. Quantitative Analysis of Retinal Structure using Spectral Domain Optical Coherence Tomography in RPGR-associated Retinopathy

      Quantitative Analysis of Retinal Structure using Spectral Domain Optical Coherence Tomography in RPGR-associated Retinopathy

      Purpose Quantification of retinal structure and progression using spectral-domain optical coherence tomography (SDOCT) in patients with retinitis pigmentosa (RP) associated with retinitis pigmentosa GTPase regulator gene ( RPGR ) mutations Design Retrospective observational case series Methods Setting: Moorfields Eye Hospital, London, United Kingdom. Subjects: Both eyes of 32 patients. SDOCT follow-up period of >1 year (3.1±1.4 years). Outcome measures: Ellipsoid zone (EZ) width (EZW), outer nuclear layer (ONL) and inner retinal layer (IRL) thickness measurements. Progression rates, interocular symmetry, association with age and genotype were investigated. Results: Significant differences were observed between baseline and final measurements of EZW and ...

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    18. Visualization of Radial Peripapillary Capillaries Using Optical Coherence Tomography Angiography: The Effect of Image Averaging

      Visualization of Radial Peripapillary Capillaries Using Optical Coherence Tomography Angiography: The Effect of Image Averaging

      Objectives To assess the effect of image registration and averaging on the visualization and quantification of the radial peripapillary capillary (RPC) network on optical coherence tomography angiography (OCTA). Methods Twenty-two healthy controls were imaged with a commercial OCTA system (AngioVue, Optovue, Inc.). Ten 10x10° scans of the optic disc were obtained, and the most superficial layer (50-μm slab extending from the inner limiting membrane) was extracted for analysis. Rigid registration was achieved using ImageJ, and averaging of each 2 to 10 frames was performed in five ~2x2° regions of interest (ROI) located 1° from the optic disc margin. The ...

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    19. Imaging the adult zebrafish cone mosaic using optical coherence tomography

      Imaging the adult zebrafish cone mosaic using optical coherence tomography

      Zebrafish ( Danio rerio ) provide many advantages as a model organism for studying ocular disease and development, and there is great interest in the ability to non-invasively assess their photoreceptor mosaic. Despite recent applications of scanning light ophthalmoscopy, fundus photography, and gonioscopy to in vivo imaging of the adult zebrafish eye, current techniques either lack accurate scaling information (limiting quantitative analyses) or require euthanizing the fish (precluding longitudinal analyses). Here we describe improved methods for imaging the adult zebrafish retina using spectral domain optical coherence tomography (OCT). Transgenic fli1:eGFP zebrafish were imaged using the Bioptigen Envisu R2200 broadband source OCT ...

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    20. Directional optical coherence tomography systems and methods

      Directional optical coherence tomography systems and methods

      An optical coherence tomography system that includes an optical device having an adjustable optical element configured to displace a pupil entry point of light is provided. Optical coherence tomography methods using the optical coherence tomography system are also provided. The subject optical coherence tomography systems and methods find use in a variety of different applications, including imaging applications.

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    21. Imaging Foveal Microvasculature: Optical Coherence Tomography Angiography Versus Adaptive Optics Scanning Light Ophthalmoscope Fluorescein Angiography

      Imaging Foveal Microvasculature: Optical Coherence Tomography Angiography Versus Adaptive Optics Scanning Light Ophthalmoscope Fluorescein Angiography

      Purpose : To compare the use of optical coherence tomography angiography (OCTA) and adaptive optics scanning light ophthalmoscope fluorescein angiography (AOSLO FA) for characterizing the foveal microvasculature in healthy and vasculopathic eyes. Methods : Four healthy controls and 11 vasculopathic patients (4 diabetic retinopathy, 4 retinal vein occlusion, and 3 sickle cell retinopathy) were imaged with OCTA and AOSLO FA. Foveal perfusion maps were semiautomatically skeletonized for quantitative analysis, which included foveal avascular zone (FAZ) metrics (area, perimeter, acircularity index) and vessel density in three concentric annular regions of interest. On each set of OCTA and AOSLO FA images, matching vessel segments ...

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    22. En Face Optical Coherence Tomography of Outer Retinal Discontinuity and Fan-Shaped Serous Macular Detachment in Diabetic Macular Edema

      En Face Optical Coherence Tomography of Outer Retinal Discontinuity and Fan-Shaped Serous Macular Detachment in Diabetic Macular Edema

      This case report describes en face optical coherence tomographic imaging of serous macular detachment secondary to retinal microangiopathy in a patient with diabetic retinopathy and macular edema. We report en face optical coherence tomographic (OCT) imaging of serous macular detachment secondary to retinal microangiopathy in a patient with diabetic retinopathy and macular edema. The en face OCT clearly delineated a fan shape of the detachment. Our findings implicate an outer retinal discontinuity as the site through which fluid may have entered the subretinal space.

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    23. DIRECTIONAL OPTICAL COHERENCE TOMOGRAPHY PROVIDES ACCURATE OUTER NUCLEAR LAYER AND HENLE FIBER LAYER MEASUREMENTS

      DIRECTIONAL OPTICAL COHERENCE TOMOGRAPHY PROVIDES ACCURATE OUTER NUCLEAR LAYER AND HENLE FIBER LAYER MEASUREMENTS

      PURPOSE: The outer nuclear layer (ONL) contains photoreceptor nuclei, and its thickness is an important biomarker for retinal degenerations. Accurate ONL thickness measurements are obscured in standard optical coherence tomography (OCT) images because of Henle fiber layer (HFL). Improved differentiation of the ONL and HFL boundary is made possible by using directional OCT, a method that purposefully varies the pupil entrance position of the OCT beam. METHODS: Fifty-seven normal eyes were imaged using multiple pupil entry positions with a commercial spectral domain OCT system. Cross-sectional image sets were registered to each other and segmented at the top of HFL, the ...

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    24. Rapid, Accurate, and Non-Invasive Measurement of Zebrafish Axial Length and Other Eye Dimensions Using SD-OCT Allows Longitudinal Analysis of Myopia and Emmetropization

      Rapid, Accurate, and Non-Invasive Measurement of Zebrafish Axial Length and Other Eye Dimensions Using SD-OCT Allows Longitudinal Analysis of Myopia and Emmetropization

      Refractive errors in vision can be caused by aberrant axial length of the eye, irregular corneal shape, or lens abnormalities. Causes of eye length overgrowth include multiple genetic loci, and visual parameters. We evaluate zebrafish as a potential animal model for studies of the genetic, cellular, and signaling basis of emmetropization and myopia. Axial length and other eye dimensions of zebrafish were measured using spectral domain-optical coherence tomography (SD-OCT). We used ocular lens and body metrics to normalize and compare eye size and relative refractive error (difference between observed retinal radial length and controls) in wild-type and lrp2 zebrafish. Zebrafish ...

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    1. (41 articles) Joseph Carroll
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