1. Articles in category: Ophthalmology

    577-600 of 6725 « 1 2 ... 22 23 24 25 26 27 28 ... 279 280 281 »
    1. Automated Three-Dimensional Image Segmentation of Retinal OCT Images (Thesis)

      Automated Three-Dimensional Image Segmentation of Retinal OCT Images (Thesis)

      Optical coherence tomography (OCT) has become an essential tool in ophthalmology. The macular OCT images are three dimensional, high resolution and cross-sectional image of macula, which provides detailed structural information of various macular layers. Moreover macular OCT imaging is non-contact, noninvasive and real-time. OCT images can be obtained quickly and multiple times, this allows easy diagnosis and treatment progress monitoring. With advances in technology acquired dataset size is also increasing, which makes it impractical to manually segment macular layers in clinical environment. Thus need of fast and accurate segmentation algorithm is ever increasing. In this thesis two segmentation algorithms have ...

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    2. Optical Coherence Tomography (OCT) – A New Diagnostic Tool in Psychiatry?

      Optical Coherence Tomography (OCT) – A New Diagnostic Tool in Psychiatry?

      Optical coherence tomography (OCT) is a non-invasive, contact-less imaging method which provides an “in vivo” representation of the retina. It allows the quantitative measurement of retinal nerve fibre layer thickness (RNFLT) and macula thickness (MT) and, in addition, is suitable to measure volumes (e. g., macula volume/MV). In the research of neurodegenerative diseases, OCT has been increasingly used and has shown its potential as a possible diagnostic tool over the course of the last few years. In recent years, the hypothesis that mental disorders like schizophrenia or unipolar depressive disorder have a degenerative component was established through a variety ...

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    3. The usefulness of multimodal imaging for differentiating pseudopapilloedema and true swelling of the optic nerve head: a review and case series

      The usefulness of multimodal imaging for differentiating pseudopapilloedema and true swelling of the optic nerve head: a review and case series

      Ophthalmic practitioners have to make a critical differential diagnosis in cases of an elevated optic nerve head. They have to discriminate between pseudopapilloedema (benign elevation of the optic nerve head) and true swelling of the optic nerve head. This decision has significant implications for appropriate patient management. Assessment of the optic disc prior to the advanced imaging techniques that are available today (particularly spectral domain optical coherence tomography and fundus autofluorescence), has mainly used diagnostic tools, such as funduscopy and retinal photography. As these traditional methods rely on the subjective assessment by the clinician, evaluation of the elevated optic nerve ...

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    4. Retinal Vascular Layers Imaged by Fluorescein Angiography and Optical Coherence Tomography Angiography

      Retinal Vascular Layers Imaged by Fluorescein Angiography and Optical Coherence Tomography Angiography

      Importance The retinal vasculature is involved in many ocular diseases that cause visual loss. Although fluorescein angiography is the criterion standard for evaluating the retina vasculature, it has risks of adverse effects and known defects in imaging all the layers of the retinal vasculature. Optical coherence tomography (OCT) angiography can image vessels based on flow characteristics and may provide improved information. Objective To investigate the ability of OCT angiography to image the vascular layers within the retina compared with conventional fluorescein angiography. Design, Setting, and Participants In this study, performed from March 14, 2014, through June 24, 2014, a total ...

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    5. Macular measurements using spectral-domain optical coherence tomography in Chinese myopic children

      Macular measurements using spectral-domain optical coherence tomography in Chinese myopic children

      Purpose:To evaluate the macular thickness/volume in Chinese myopic children using spectral-domain optical coherence tomography (Cirrus HD-OCT; Carl Zeiss Meditec, Dublin, CA, USA) and assess its correlation with spherical equivalent refraction (SE), axial length (AL), sex and age. Methods:A total of 194 eyes from 194 children (aged 6-17 years old) with emmetropia (-0.5D<SE≤0.5D), low myopia (-3.0D<SE≤-0.5D) and moderate to high myopia (SE≤-3.0D) were recruited in the study. Each child underwent standardized ophthalmic examinations including visual acuity (VA), cycloplegic refraction and AL measurement. The macular thickness for the nine ...

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    6. Evolution of vitreomacular adhesion to acute vitreofoveal separation with special emphasis on a traction-induced foveal pathology. A prospective study of spectral-domain optical coherence tomography

      Evolution of vitreomacular adhesion to acute vitreofoveal separation with special emphasis on a traction-induced foveal pathology. A prospective study of spectral-domain optical coherence tomography

      Purpose To investigate the evolution of vitreomacular adhesion (VMA) to acute vitreofoveal separation with particular emphasis on cases involving the underlying fovea. Methods In this observational case series, of 192 cases in the VMA stage, 51 progressed to acute vitreofoveal separation; this subgroup was divided into those with normal separation (Group I) and those with co-existing macular findings (Group II). All patients were examined using spectral domain-optical coherence tomography (SD-OCT) at regular three-month intervals. We recorded the best-corrected visual acuity (BCVA), the vitreomacular angle of the VMA (nasally and temporally), the horizontal diameter of the VMA, the macular thickness, the ...

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    7. HEYEX PACS™: The Next Generation Image Management and Device Integration Platform

      HEYEX PACS™: The Next Generation Image Management and Device Integration Platform

      Heidelberg Engineering GmbH announces an ophthalmic picture archiving and communication system (PACS) platform at AAO 2014 in Chicago. “This new picture archiving and communication system (PACS) is a big step forward for our customers,” said Dr. Kester Nahen, Managing Director of Heidelberg Engineering. “The HEYEX PACS software platform will not only support Heidelberg Engineering devices but also integrate imaging devices of other manufacturers and diagnostic data into a centralized database. This will enable our customers to access, review, and compare all clinical images in one central application. HEYEX PACS allows us to offer a comprehensive image management and device integration ...

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    8. Comparative Diagnostic Accuracy of Ganglion Cell-Inner Plexiform and Retinal Nerve Fiber Layer Thickness Measures by Cirrus and Spectralis Optical Coherence Tomography in Relapsing-Remitting Multiple Sclerosis

      Comparative Diagnostic Accuracy of Ganglion Cell-Inner Plexiform and Retinal Nerve Fiber Layer Thickness Measures by Cirrus and Spectralis Optical Coherence Tomography in Relapsing-Remitting Multiple Sclerosis

      Objective . To estimate sensitivity and specificity of several optical coherence tomography (OCT) measurements for detecting retinal thickness changes in patients with relapsing-remitting multiple sclerosis (RRMS), such as macular ganglion cell-inner plexiform layer (GCIPL) thickness measured with Cirrus (OCT) and peripapillary retinal nerve fiber layer (pRNFL) thickness measured with Cirrus and Spectralis OCT. Methods . Seventy patients (140 eyes) with RRMS and seventy matched healthy subjects underwent pRNFL and GCIPL thickness analysis using Cirrus OCT and pRNFL using Spectralis OCT. A prospective, cross-sectional evaluation of sensitivities and specificities was performed using latent class analysis due to the absence of a gold standard ...

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    9. Exact Surface Registration of Retinal Surfaces From 3D Optical Coherence Tomography Images

      Exact Surface Registration of Retinal Surfaces From 3D Optical Coherence Tomography Images

      Nonrigid registration of optical coherence tomography (OCT) images is an important problem in studying eye diseases, evaluating the effect of pharmaceuticals in treating vision loss, and performing group-wise cross-sectional analysis. High dimensional nonrigid registration algorithms required for cross-sectional and longitudinal analysis are still being developed for accurate registration of OCT image volumes, with the speckle noise in images presenting a challenge for registration. Development of algorithms for segmentation of OCT images to generate surface models of retinal layers has advanced considerably and several algorithms are now available that can segment retinal OCT images into constituent retinal surfaces. Important morphometric measurements ...

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    10. In vitro 3D anterior segment imaging in lamb eye with extended depth range swept source optical coherence tomography

      In vitro 3D anterior segment imaging in lamb eye with extended depth range swept source optical coherence tomography

      A complex conjugate resolved, extended depth range, high speed 1 μm swept-source optical coherence tomography (SSOCT) provides a dense three-dimensional (3-D) imaging of the entire anterior segment of eye. SSOCT system utilizes “coherence revival” characteristics of the light source (external cavity tunable laser, ECTL), which is automatically phase modulated. We describe implementation of this with a common swept laser with built-in k-clock to allow imaging in high depth range, 10.5 mm in air, without any external MZI clock. The system is capable of generating long depth range without any modulators or frequency shifter. Most of the commercially available OCT ...

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    11. Retinal Vascular Layers in Macular Telangiectasia Type 2 Imaged by Optical Coherence Tomographic Angiography

      Retinal Vascular Layers in Macular Telangiectasia Type 2 Imaged by Optical Coherence Tomographic Angiography

      Importance Macular telangiectasia type 2 (MacTel 2) is a rare disease in which abnormalities of the retinal vasculature play a key role. The vascular abnormalities are typically evaluated using fluorescein angiography, a modality with known defects in imaging the deeper layers of the retinal vasculature. Angiography based on optical coherence tomography can image vessels based on flow characteristics without dye injection and may provide improved information concerning the pathophysiology of MacTel 2. Objective To investigate MacTel 2 using optical coherence tomographic angiography. Design, Setting, and Participants Fourteen eyes of 7 patients with MacTel 2 were analyzed in a community-based retina ...

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    12. Blood Components and OCT Reflectivity Evaluated in Animal Model

      Blood Components and OCT Reflectivity Evaluated in Animal Model

      Background/purpose : To see the relationship between blood components and optical coherence tomography ( OCT ) reflectivity using an animal model in which the aqueous humor was substituted by different experimental solutions without changing the integrity of the retina. Materials and methods : The aqueous humor of an enucleated swine eye was replaced with plasma obtained from healthy volunteers. The OCT reflectivity of the anterior chamber filled with each plasma was calculated from individual OCT images, and was expressed by an arbitrary unit (AU). The concentration of blood components such as cholesterol, hemoglobin (Hb) and bilirubin of each individual was measured, and the ...

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      Mentions: Taiji Sakamoto
    13. Prediction of Residual Astigmatism After Cataract Surgery Using Swept Source Fourier Domain Optical Coherence Tomography

      Prediction of Residual Astigmatism After Cataract Surgery Using Swept Source Fourier Domain Optical Coherence Tomography

      Purpose : To compare corneal measurements obtained by a swept source fourier domain OCT (CASIA SS-1000), an autokeratometer (Haag-Streit Lenstar), a hybrid topographer (Tomey TMS-5), a Placido topographer (Tomey TMS-5 in Placido mode) and a Scheimpflug tomographer (Oculus Pentacam) to manifest subjective refraction. Methods : One hundred and four pseudophacic patients with non-toric IOLs were measured at least 6 months after surgery . Corneal astigmatism as measured on the anterior corneal surface as well as total corneal astigmatism including posterior surface data was compared to manifest refractive cylinder (cross-cylinder strategy) by computing difference vectors and correlation analysis of power vectors. Results : The OCT ...

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    14. Diagnosis of subretinal neovascularization associated with idiopathic juxtafoveal retinal telangiectasia — fluorescein angiography versus spectral-domain optical coherence tomography — can we choose?

      Diagnosis of subretinal neovascularization associated with idiopathic juxtafoveal retinal telangiectasia — fluorescein angiography versus spectral-domain optical coherence tomography — can we choose?

      Dear Editor We read with great interest the article entitled ”Diagnosis of subretinal neovascularization associated with idiopathic juxtafoveal retinal telangiectasia—fluorescein angiography versus spectral-domain optical coherence tomography by Chhablani J et al. [ 1 ]. This article compares the ability of fundus fluorescein angiography (FFA) and spectral-domain optical coherence tomography (SD-OCT) to diagnose subretinal neovascularization (SRNV) secondary to idiopathic juxtafoveal retinal telangiectasia (IJRT) type 2A, and also highlights the pitfalls of FFA and OCT in detecting and confirming SRNV in cases of IJRT type 2. However we have made the following observations

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    15. Functional and Morphological Changes after Macular Pucker Surgery: An Optical Coherence Tomography and Microperimetric Study

      Functional and Morphological Changes after Macular Pucker Surgery: An Optical Coherence Tomography and Microperimetric Study

      Purpose: To investigate the relationship among functional and morphological findings before and after macular pucker surgery. Methods: Thirty-eight eyes with idiopathic macular pucker that underwent 25-gauge vitrectomy and infracyanine green-assisted internal limiting membrane peeling were prospectively enrolled. Main outcome measures were best-corrected visual acuity (BCVA), spectral-domain optical coherence tomography findings and MP-1 microperimetry findings. Results: Mean BCVA improvement was 0.34 logMAR (p < 0.0001). Mean central retinal thickness (CRT) reduction was 50 µm (p = 0.0041). Mean retinal sensitivity improvement was 0.9. Patients with a greater improvement of postoperative BCVA showed worse baseline BCVA (p < 0.001), shorter ...

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    16. Quantitative SD-OCT Imaging Biomarkers as Indicators of Age-Related Macular Degeneration Progression

      Quantitative SD-OCT Imaging Biomarkers as Indicators of Age-Related Macular Degeneration Progression

      Purpose: We developed a statistical model based on quantitative characteristics of drusen to estimate the likelihood of conversion from early and intermediate age-related macular degeneration (AMD) to its advanced exudative form (AMD progression) in the short term (less than 5 years), a crucial task to enable early intervention and improve outcomes. Methods: Image features of drusen quantifying their number, morphology, and reflectivity properties, as well as the longitudinal evolution in these characteristics, were automatically extracted from 2146 spectral domain optical coherence tomography (SD-OCT) scans of 330 AMD eyes in 244 patients collected over a period of 5 years, with 36 ...

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    17. Advanced Optical Coherence Tomography Applications for the Retina Specialist Activity - Ophthalmology Education Lab

      Advanced Optical Coherence Tomography Applications for the Retina Specialist Activity - Ophthalmology Education Lab

      Advances in retinal pharmacology have significantly improved outcomes for patients with a range of chronic retinal conditions, including age-related macular degeneration, macular edema, retinal vascular disorders and diseases of the vitreomacular interface. Maximizing the efficacy of available treatments requires the appropriate use of optical coherence tomography (OCT) to diagnose these conditions and to monitor the efficacy of treatment. In this monograph, leading clinicians and researchers the role of OCT in detecting structural changes associated with a range of retinal diseases and provide clinical pearls on using tools such as thickness maps, automated change analysis, and angiography in the practical management ...

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    18. Effect of Hemodialysis on Retinal Thickness in Patients with Diabetic Retinopathy, with and without Macular Edema, Using Optical Coherence Tomography

      Effect of Hemodialysis on Retinal Thickness in Patients with Diabetic Retinopathy, with and without Macular Edema, Using Optical Coherence Tomography

      Background. Effects of hemodialysis (HD) treatment on retinal thickness and macular edema are unclear. Objective. To evaluate changes in retinal thickness using optical coherence tomography (OCT) in end stage renal disease (ESRD) patients with diabetic retinopathy (DR), with and without diabetic macular edema (DME), undergoing HD. Methods. Nonrandomized prospective study. Forty eyes of DR patients with ESRD treated with HD were divided into two groups: patients with macular edema and patients without macular edema. Both eyes were analyzed. Patients underwent an ophthalmic examination including OCT measurements of retinal thickness, blood albumin and hemoglobin A1C levels, blood pressure, and body weight ...

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    19. Influence of axial length on thickness measurements using spectral domain optical coherence tomography

      Influence of axial length on thickness measurements using spectral domain optical coherence tomography

      Purpose:To assess the influence of axial length on spectral domain optical coherence tomography (SD OCT) thickness measurements in patients with subretinal visual implant. Methods:Data from eight emmetropic pseudophakic eyes of eight patients with subretinal visual implant were analyzed retrospectively. These patients participated in the monocentric part of a multicentre trial (www.clinicaltrials.gov number: NCT01024803). The axial length was measured in three short (< 22.5 mm), three medium (22.51-25.50 mm) and two long (> 25.52 mm) eyes. Using Heidelberg Spectralis, the known thickness of subretinal implant microchip (70 µm) was measured on 15 images per eye ...

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    20. Retinal imaging study to focus on early intervention

      Retinal imaging study to focus on early intervention

      UK firm Optos in potential £10M collaboration aiming for early detection of sight-threatening diseases. Optomap retinal imaging A new laser-based imaging technology for early detection of a range of serious eye diseases is set for a clinical study in the UK. Dunfermline-based Optos , which is listed on the London Stock Exchange, will work with Kent and Strathclyde Universities to develop a system that monitors the function of cells in patients’ eyes. The technology will then be used in clinical trials in Scotland, with the aim of detecting major sight-threatening diseases like glaucoma, age-related macular degeneration (AMD) and diabetic retinopathy in ...

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    21. Retinal Vascular Layers Imaged by Fluorescein Angiography and Optical Coherence Tomography Angiography

      Retinal Vascular Layers Imaged by Fluorescein Angiography and Optical Coherence Tomography Angiography

      Importance The retinal vasculature is involved in many ocular diseases that cause visual loss. Although fluorescein angiography is the criterion standard for evaluating the retina vasculature, it has risks of adverse effects and known defects in imaging all the layers of the retinal vasculature. Optical coherence tomography (OCT) angiography can image vessels based on flow characteristics and may provide improved information. Objective To investigate the ability of OCT angiography to image the vascular layers within the retina compared with conventional fluorescein angiography. Design, Setting, and Participants In this study, performed from March 14, 2014, through June 24, 2014, a total ...

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    22. Comparative Kitasato-type optical coherence tomography study of differences in scleral shapes between the superonasal and superotemporal quadrants

      Comparative Kitasato-type optical coherence tomography study of differences in scleral shapes between the superonasal and superotemporal quadrants

      Objective: To determine differences in the scleral shape between the superonasal and superotemporal quadrants, which are the sites of scleral flap creation in trabeculectomy, using anterior-segment optical coherence tomography (OCT). Methods: Thirty-eight eyes of 22 subjects without ocular diseases except for cataract or ametropia were enrolled. The mean patient age was 63.8 ± 15.7 years (range, 28−80 years). The same examiner captured all images using Kitasato-type anterior-segment swept-source OCT. The mean measurements were calculated from the three images captured 60 degrees from the horizontal line passing through the pupillary center in the superonasal and superotemporal sclera. The radius ...

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    23. Optical coherence tomography of fovea before and after laser treatment in retinopathy of prematurity

      Optical coherence tomography of fovea before and after laser treatment in retinopathy of prematurity

      Purpose: To study the fovea in preterm babies with Type I retinopathy of prematurity (ROP) before and after laser treatment using optical coherence tomography (OCT). Materials and Methods: This was a prospective observational case-control study including preterm neonates undergoing screening for ROP from May 2009 to July 2011. Group 1 included 30 eyes of 15 neonates with Type I ROP. A 532-nm laser was used for treatment in all cases for Group 1. Group 2 included 14 eyes of 7 preterm neonates without ROP that served as controls. OCT was performed under sedation in the lateral position before and after ...

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    24. Spectral-Domain Optical Coherence Tomography of Emulsified Subretinal Silicone Oil Presenting as a Macular Inverted Pseudohypopyon

      Spectral-Domain Optical Coherence Tomography of Emulsified Subretinal Silicone Oil Presenting as a Macular Inverted Pseudohypopyon

      The authors present a rare case of an inverted pseudohypopyon due to subretinal emulsified silicone oil in the macula of a patient who underwent pars plana vitrectomy surgery for repair of retinal detachment with proliferative vitreoretinopathy 1 year prior to presentation of this finding. The patient’s predisposing diagnosis is pathologic myopia.

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