1. Articles in category: Ophthalmology

    553-576 of 8134 « 1 2 ... 21 22 23 24 25 26 27 ... 337 338 339 »
    1. Optic Disc Vascularization in Glaucoma: Value of Spectral-Domain Optical Coherence Tomography Angiography

      Optic Disc Vascularization in Glaucoma: Value of Spectral-Domain Optical Coherence Tomography Angiography

      Purpose . To detect changes in optic nerve head (ONH) vascularization in glaucoma patients using spectral-domain OCT angiography (OCT-A). Material and Method . Fifty glaucoma patients and 30 normal subjects were evaluated with OCT-A (AngioVue®, Optovue). The total ONH vessel density and temporal disc vessel density were measured. Clinical data, visual field (VF) parameters, and spectral-domain OCT evaluation (RNFL: retinal nerve fiber layer thickness, GCC: ganglion cell complex thickness, and rim area) were recorded for glaucoma patients. Correlations among total and temporal ONH vessel density and structural and VF parameters were analyzed. Results . In the glaucoma group, total and temporal ONH vessel ...

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      Mentions: Optovue
    2. Visual response and anatomical changes on sequential spectral-domain optical coherence tomography in birdshot chorioretinopathy treated with local corticosteroid therapy

      Visual response and anatomical changes on sequential spectral-domain optical coherence tomography in birdshot chorioretinopathy treated with local corticosteroid therapy

      Background Birdshot chorioretinopathy is a chronic bilateral inflammatory disease of unknown etiology characterized by bilateral retinal vasculitis, mild to moderate vitritis, retinal vascular leakage, cystoid macular edema (CME), and typical “birdshot” chorioretinal lesions. Typically, patients with birdshot chorioretinopathy are treated with systemic immunosuppressive and/or corticosteroid therapy in an effort to minimize loss of vision. Spectral-domain OCT (SD-OCT) has shown regional or generalized photoreceptor loss in addition to both retinal as well as choroidal thinning in these patients. The present study describes anatomical changes of the retina and alterations in choroidal thickness and vasculature on sequential spectral-domain optical coherence tomography ...

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    3. Intraoperative OCT Pachymetry in Patients Undergoing Dextran-Free Riboflavin UVA Accelerated Corneal Collagen Crosslinkin

      Intraoperative OCT Pachymetry in Patients Undergoing Dextran-Free Riboflavin UVA Accelerated Corneal Collagen Crosslinkin

      Purpose : To assess intraoperative corneal pachymetry in patients undergoing accelerated corneal collagen crosslinking with a dextran-free riboflavin solution. Methods : Prospective, non-comparative, multicenter interventional study. Thirty patients with progressive keratoconus were enrolled in the study from the Siena Crosslinking Center™ in Siena, Italy and the Eye Center in Catanzaro, Italy. The mean age was 26.9 ± 6.5 years. Patients underwent pulsed light accelerated crosslinking (PL-ACXL) by KXL I UV-A source (Avedro Inc., Waltham, MS, USA) with 8 min (1 s on/1 s off) of UV-A exposure, 30 mW/cm 2 and an energy dose of 7.2 J/cm ...

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    4. A STUDY TO COMPARE FUNDUS FLUORESCEIN ANGIOGRAPHY AND OPTICAL COHERENCE TOMOGRAPHY IN AGE RELATED MACULAR DEGENERATION

      A STUDY TO COMPARE FUNDUS FLUORESCEIN ANGIOGRAPHY AND OPTICAL COHERENCE TOMOGRAPHY IN AGE RELATED MACULAR DEGENERATION

      PURPOSE To compare the diagnostic accuracy of optical coherence tomography with Fundus Fluorescein Angiography in diagnosing Age related macular degeneration. METHODS A total 25 patients newly diagnosed as Age related macular degeneration were included in the study. The study was done during the time period between August 2013 to November 2015 this is a prospective randomized hospital based study. RESULTS Maximum no of patients affected belonged to the age group of 50-70 years and 60% were females. The most common symptom was defective vision accounting for 92%. Hypertension and hyperlipidemia were the most common risk factors. 12% of the cases ...

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    5. Quantitative spectral domain optical coherence tomography thickness parameters in type II diabetes

      Quantitative spectral domain optical coherence tomography thickness parameters in type II diabetes

      Purpose: To elucidate the changes in retinal thickness and individual layer thickness in subjects with diabetic retinopathy (DR) using spectral domain optical coherence tomography (SDOCT). Materials and Methods: A total of 251 eyes from 170 subjects were included in this study. The study sample was subdivided into nondiabetic subjects; subjects with diabetes but no DR; subjects with mild, moderate, and severe nonproliferative DR (NPDR); and proliferative DR. Various retinal thickness parameters were assessed using SDOCT. Results: The mean age of the study population was 55.34 ± 9.02 years (range: 32-80 years) and 56.6% of the subjects were males ...

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    6. Clinical utility of anterior segment swept-source optical coherence tomography in glaucoma

      Clinical utility of anterior segment swept-source optical coherence tomography in glaucoma

      Optical coherence tomography (OCT), a noninvasive imaging modality that uses low-coherence light to obtain a high-resolution cross-section of biological structures, has evolved dramatically over the years. The Swept-source OCT (SS-OCT) makes use of a single detector with a rapidly tunable laser as a light source. The Casia SS-1000 OCT is a Fourier-domain, SS-OCT designed specifically for imaging the anterior segment. This system achieves high resolution imaging of 10΅m (Axial) and 30΅m (Transverse) and high speed scanning of 30,000 A-scans per second. With a substantial improvement in scan speed, the anterior chamber angles can be imaged 360 degrees ...

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    7. Enhancement and bias removal of optical coherence tomography images: An iterative approach with adaptive bilateral filtering

      Enhancement and bias removal of optical coherence tomography images: An iterative approach with adaptive bilateral filtering

      Optical coherence tomography (OCT) has continually evolved and expanded as one of the most valuable routine tests in ophthalmology. However, noise (speckle) in the acquired images causes quality degradation of OCT images and makes it difficult to analyze the acquired images. In this paper, an iterative approach based on bilateral filtering is proposed for speckle reduction in multiframe OCT data. Gamma noise model is assumed for the observed OCT image. First, the adaptive version of the conventional bilateral filter is applied to enhance the multiframe OCT data and then the bias due to noise is reduced from each of the ...

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    8. Optical Coherence Tomography and OCT Angiography (Textbook)

      Optical Coherence Tomography and OCT Angiography (Textbook)

      OCT angiography (OCTA) is a revolutionary imaging modality that allows visualization of the vascular flow in the retina and choroid en vivo. Optical Coherence Tomography and OCT Angiography is a comprehensive guide that explains the science of OCT and OCT angiography, as well as clinical interpretation of images. As OCT angiography becomes the clinical standard, it is imperative to develop the nomenclature and descriptive interpretation to guide diagnosis and treatment. This book is intended for use by clinicians, technicians and imagers to develop a standard vocabulary and help guide the user towards more accurate assessment, and promises to be the ...

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    9. Optical Coherence Tomography Assessment Before and After Vitamin Supplementation in a Patient With Vitamin A Deficiency: A Case Report and Literature Review

      Optical Coherence Tomography Assessment Before and After Vitamin Supplementation in a Patient With Vitamin A Deficiency: A Case Report and Literature Review

      Abstract: Vitamin A is an essential fat-soluble vitamin important for the function of various body systems. In the eye, vitamin A is essential for the synthesis of visual pigments in photoreceptors. Vitamin A deficiency is a rare condition in the developed countries and might follow bariatric or intestinal bypass surgery. We present the case of a 67-year-old male that complained of visual loss and nyctalopia. Patient had bariatric surgery 15 years before for weight loss. Low serum levels of vitamin A confirmed the diagnosis and patient started vitamin A supplementation. Visual fields, macular thickness, and ganglion cell layer thickness were ...

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    10. Optical coherence tomography based microangiography findings in hydroxychloroquine toxicity

      Optical coherence tomography based microangiography findings in hydroxychloroquine toxicity

      Optical coherence tomography based microangiography (OMAG) is a new, non-invasive imaging modality capable of providing three dimentional (3D) retinal and choroidal microvascular maps without a need for exogenous dye. In this study, we evaluated the retinal and choroidal microvascular architecture of the macula in a patient with hydroxychloroquine (HCQ) toxicity using OMAG. Detailed microvascular information of the retina and the underlying choroid showed loss of parafoveal outer retinal vasculature with sparing of the central fovea vasculature.

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    11. Retinal optical coherence tomography at 1  μm with dynamic focus control and axial motion tracking

      Retinal optical coherence tomography at 1  μm with dynamic focus control and axial motion tracking

      High-resolution optical coherence tomography (OCT) retinal imaging is important to noninvasively visualize the various retinal structures to aid in better understanding of the pathogenesis of vision-robbing diseases. However, conventional OCT systems have a trade-off between lateral resolution and depth-of-focus. In this report, we present the development of a focus-stacking OCT system with automatic focus optimization for high-resolution, extended-focal-range clinical retinal imaging by incorporating a variable-focus liquid lens into the sample arm optics. Retinal layer tracking and selection was performed using a graphics processing unit accelerated processing platform for focus optimization, providing real-time layer-specific en face visualization. After optimization, multiple volumes ...

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    12. Intraoperative OCT Pachymetry in Patients Undergoing Dextran-Free Riboflavin UVA Accelerated Corneal Collagen Crosslinking

      Intraoperative OCT Pachymetry in Patients Undergoing Dextran-Free Riboflavin UVA Accelerated Corneal Collagen Crosslinking

      Purpose : To assess intraoperative corneal pachymetry in patients undergoing accelerated corneal collagen crosslinking with a dextran-free riboflavin solution. Methods : Prospective, non-comparative, multicenter interventional study. Thirty patients with progressive keratoconus were enrolled in the study from the Siena Crosslinking Center™ in Siena, Italy and the Eye Center in Catanzaro, Italy. The mean age was 26.9 ± 6.5 years. Patients underwent pulsed light accelerated crosslinking (PL-ACXL) by KXL I UV-A source (Avedro Inc., Waltham, MS, USA) with 8 min (1 s on/1 s off) of UV-A exposure, 30 mW/cm 2 and an energy dose of 7.2 J/cm ...

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    13. Detection of preperimetric glaucoma using Bruch membrane opening, neural canal and posterior pole asymmetry analysis of optical coherence tomography

      Detection of preperimetric glaucoma using Bruch membrane opening, neural canal and posterior pole asymmetry analysis of optical coherence tomography

      We analysed retinal nerve fibre layer (RNFL) defects in eyes with normal circumpapillary RNFL (cpRNFL) thickness using posterior pole asymmetry analysis (PPAA) and investigated the parameters of Bruch membrane opening (BMO) and neural canals using enhanced depth imaging spectral domain optical coherence tomography (EDI-SDOCT). A total of 112 preperimetric glaucomatous eyes of 92 patients were examined to obtain cpRNFL thickness using SD-OCT. Posterior pole asymmetry analysis (PPAA) and central cross-sectional images of the optic nerve head (ONH) were obtained using EDI-SDOCT. Minimal and horizontal distances between the BMO and ONH surfaces (BMOM, BMOH) and the terminal of retinal pigment epithelium ...

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    14. Optical Coherence Tomography Imaging for Glaucoma – Today and Tomorrow

      Optical Coherence Tomography Imaging for Glaucoma – Today and Tomorrow

      Abstract: Digital imaging technologies for glaucoma diagnostics have evolved rapidly over the recent years. From time-domain optical coherence tomography (OCT) to spectral-domain and swept-source OCTs, the application of OCT for analysis of the anterior chamber angle and the optic nerve head (ONH) is expanding. The second-generation anterior segment swept-source OCT is able to image the configuration of the anterior chamber angle in 3 dimensions in less than 1 second and perform 360-degree analysis of the anterior chamber angle width for detection of angle closure. The morphology, density, and dimensions of the crystalline lens in relation to the anterior chamber can ...

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    15. Comparability of retinal thickness measurements using different scanning protocols on spectral-domain optical coherence tomography

      Comparability of retinal thickness measurements using different scanning protocols on spectral-domain optical coherence tomography

      Retinal thickness measurements obtained using optical coherence tomography (OCT) play an essential role both in multi-center clinical trials and in normal clinical practice. Different scanning protocols are available on most OCT devices, and it is important to ascertain whether the retinal thickness measurements obtained from these are comparable. This study aimed to compare retinal thickness measurements between raster and radial scanning protocols using spectral-domain OCT (SD-OCT). In a prospective study, 32 healthy subjects were scanned sequentially using raster and radial protocols from a SD-OCT device. For both the raster and radial OCT scans, retinal thicknesses were measured manually subfoveally and ...

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    16. Neuro-Ophthalmology of Space Flight

      Neuro-Ophthalmology of Space Flight

      Background: To describe the history, clinical findings, and possible pathogenic etiologies of the constellation of neuro-ophthalmic findings discovered in astronauts after long-duration space flight and to discuss the terrestrial implications of such findings. Evidence Acquisition: Retrospective review of published observational, longitudinal examination of neuro-ophthalmic findings in astronauts after long-duration space flight; analysis of postflight questionnaires regarding in-flight vision changes in approximately 300 additional astronauts; and hypothesis generating for developing possible future countermeasures and potential implications for neuro-ophthalmic disorders on Earth. Astronauts with neuro-ophthalmic findings, which were not present at the start of a space flight mission and only seen on ...

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    17. Distinguishing Diabetic Macular Edema From Capillary Nonperfusion Using Optical Coherence Tomography Angiography

      Distinguishing Diabetic Macular Edema From Capillary Nonperfusion Using Optical Coherence Tomography Angiography

      BACKGROUND AND OBJECTIVE: To describe the appearance of diabetic macular edema (DME) using optical coherence tomography angiography (OCTA) and distinguish it from capillary nonperfusion. .. PATIENTS AND METHODS: Patients with DME were recruited for OCTA imaging. Eyes with confounding retinal diseases were excluded. Using 3 mm × 3 mm OCT angiograms segmented into the superficial and deep inner retinal vascular plexuses, two graders described the appearance of DME and confirmed the diagnosis with structural OCT and fluorescein angiography. RESULTS: DME was evaluated in 17 eyes of 12 patients. The cystoid spaces in DME appeared completely devoid of flow on the OCT angiograms ...

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    18. Evaluation of Preretinal Neovascularization in Proliferative Diabetic Retinopathy Using Optical Coherence Tomography Angiography

      Evaluation of Preretinal Neovascularization in Proliferative Diabetic Retinopathy Using Optical Coherence Tomography Angiography

      BACKGROUND AND OBJECTIVE: To describe a method for visualizing preretinal neovascularization in proliferative diabetic retinopathy (PDR) using optical coherence tomography angiography (OCTA) and report the findings in the surrounding vasculature. PATIENTS AND METHODS: Patients with PDR diagnosed on clinical examination who received OCTA scans using the RTVue XR Avanti (Optovue, Fremont, CA) were evaluated. To visualize preretinal neovascularization, OCT angiograms were segmented to project vasculature above the internal limiting membrane (ILM). OCT angiograms were segmented between the ILM and Bruch's membrane to show adjacent retinal vasculature. RESULTS: Thirteen eyes were determined to have preretinal neovascularization in the posterior pole ...

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    19. Analysis of Choroidal and Retinal Vasculature in Inherited Retinal Degenerations Using Optical Coherence Tomography Angiography

      Analysis of Choroidal and Retinal Vasculature in Inherited Retinal Degenerations Using Optical Coherence Tomography Angiography

      BACKGROUND AND OBJECTIVE: To describe the retinal vasculature and choriocapillaris, as well as the transition zone between the diseased and healthy tissue, in eyes with inherited retinal degenerations using optical coherence tomography angiography (OCTA). . PATIENTS AND METHODS: Patients with inherited retinal degenerations were recruited for OCTA imaging. Retinal vasculature was assessed for increased intercapillary space and foveal avascular zone abnormalities. Choriocapillaris, retinal pigment epithelium (RPE), and photoreceptor disruption were noted, and the borders were evaluated to speculate which layers become affected first. RESULTS: Fourteen eyes of seven subjects with inherited retinal degenerations were included. All eyes (100%) demonstrated retinal thinning ...

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    20. En Face Optical Coherence Tomography and Optical Coherence Tomography Angiography Imaging of Taxane-Associated Cystoid Macular Edema

      En Face Optical Coherence Tomography and Optical Coherence Tomography Angiography Imaging of Taxane-Associated Cystoid Macular Edema

      The taxanes are chemotherapeutic agents that may, in rare cases, cause cystoid macular edema without leakage on fluorescein angiography. Two patients with evidence of taxane-related macular edema presented and were evaluated using novel en face optical coherence tomography (OCT) and OCT angiography (OCTA) imaging modalities. Although OCTA revealed no flow abnormalities in either patient, en face OCT revealed a striking bilateral symmetric cystic tessellation pattern.

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    21. Early Swept-Source Optical Coherence Tomography Angiography Findings in Unilateral Acute Idiopathic Maculopathy

      Early Swept-Source Optical Coherence Tomography Angiography Findings in Unilateral Acute Idiopathic Maculopathy

      Unilateral acute idiopathic maculopathy (UAIM) is a rare disorder presenting in young people with an acute onset of unilateral central visual loss often associated with a prodromal flu-like illness. The authors present the early anatomical findings of a 35-year-old man clinically diagnosed with UAIM using swept-source optical coherence tomography (SS-OCT) and SS-OCT angiography.

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    22. Anterior ocular segment tomographic image analysis method and anterior ocular segment tomographic image analysis apparatus

      Anterior ocular segment tomographic image analysis method and anterior ocular segment tomographic image analysis apparatus

      To determine an opening degree of a chamber angle with higher accuracy compared to that of a conventional technology, provided is an anterior ocular segment tomographic image analysis method including: a first determination step of determining an approximated line that approximates a shape of an anterior surface of an iris along the anterior surface of the iris in an anterior ocular segment tomographic image; a second determination step of determining an approximated line extended part obtained by extending the approximated line until the approximated line crosses a baseline in contact with an inner surface of a cornea and an inner ...

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    23. Ophthalmic imaging apparatus

      Ophthalmic imaging apparatus

      There is provided an ophthalmic imaging apparatus including an optical coherence tomography (OCT) optical system for acquiring a tomographic image of a subject eye, an observation optical system configured to acquire a front image of the subject eye. The apparatus functions as an image generation unit which repeatedly generates the tomographic image based on an output signal from the OCT optical system, and repeatedly generates the front image based on an output signal from the observation optical system, a determination unit which detects a positional deviation between a reference front image and each of front images generated by the image ...

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      Mentions: Nidek
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