1. Articles in category: Ophthalmology

    577-600 of 6049 « 1 2 ... 22 23 24 25 26 27 28 ... 250 251 252 »
    1. Three-dimensional Optical Coherence Tomography Evaluation of Vascular Changes at Arteriovenous Crossings

      Three-dimensional Optical Coherence Tomography Evaluation of Vascular Changes at Arteriovenous Crossings

      Purpose:To study the three-dimensional morphological features of retinal arteriovenous crossings with optical coherence tomography (OCT) and elucidate the vascular changes associated with crossing phenomena as seen on fundus photographs. Methods: We examined 150 consecutive eyes with no ocular disease. In each eye, fundus photographs were taken, and one randomly selected arteriovenous crossing was examined by OCT. The OCT analysis was performed using sequential thin sections along and perpendicular to the retinal vessels. Results:OCT analysis of these arteriovenous crossings showed that the veins abruptly changed their directions to pass the artery and frequently displayed focal luminal narrowing with no ...

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    2. Quantifying disrupted outer retina-subretinal layer in SD-OCT images in choroidal neovascularization

      Quantifying disrupted outer retina-subretinal layer in SD-OCT images in choroidal neovascularization

      Purpose: To report a fully automated method to identify and quantify the thickness of the outer retinal-subretinal (ORSR) layer from clinical spectral-domain optical coherence tomography (SD-OCT) scans of choroidal neovascularization (CNV) due to exudative age-related macular degeneration (e-AMD). Methods: 23 Subjects with CNV met eligibility. Volumetric SD-OCT scans of 23 eyes were obtained (Zeiss Cirrus, 200×200×1024 voxels). In a subset of eyes, scans were repeated. OCT volumes were analyzed using our standard parameters and using a 3D graph-search approach with an adaptive cost function. A retinal specialist graded the segmentation as generally accurate, local segmentation inaccuracies, or failure ...

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    3. Choroidal Lymphoma Shows Calm, Rippled, or Undulating Topography on Enhanced Depth Imaging Optical Coherence Tomography in 14 Eyes

      Choroidal Lymphoma Shows Calm, Rippled, or Undulating Topography on Enhanced Depth Imaging Optical Coherence Tomography in 14 Eyes

      Purpose: To describe the features of choroidal lymphoma on enhanced depth imaging optical coherence tomography. Methods: This retrospective observational case series included 14 eyes of 13 patients, with choroidal lymphoma, studied by enhanced depth imaging optical coherence tomography. Results: The mean age at presentation was 63 years (median, 65 years; range, 32-87 years). Systemic lymphoproliferative disease was present in 2 cases as non-Hodgkin lymphoma (n = 1) or Waldenstrom macroglobulinemia (n = 1). On clinical examination, the choroidal infiltrate was classified as unifocal (n = 3), multifocal (n = 4), or diffuse (n = 7). Enhanced depth imaging optical coherence tomography scans through the tumor ...

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    4. Correction of motion artifact in 3D retinal optical coherence tomography imaging

      Correction of motion artifact in 3D retinal optical coherence tomography imaging

      In the system of spectral domain optical coherence tomography(SD-OCT), the location accuracy of scanning mechanism, mechanical dither and unconscious movement of human eyes can lead to the dither of cross-sectional scanning signal (B-scans) and affect the imaging quality of eyes. In this paper, we firstly make space transformation and filtering towards to the original retina images. Secondly, we find out the characteristic curve, which is called inner segment/outer segment (IS/OS) layer, and its location based on mathematical morphology opening and closing operation segmentation image and canny algorithm. Then we use the method of smoothing spline curve fitting ...

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    5. A Bibliometric Analysis of Optic Coherence Tomography Studies in Multiple Sclerosis

      A Bibliometric Analysis of Optic Coherence Tomography Studies in  Multiple Sclerosis

      igh-resolution cross-sectional images of the retina that has been used for ten years in multiple sclerosis (MS) related optic neuropathies. The objective of this study is to determine the scientific output in use of OCT in multiple sclerosis between 1982 and 2012 using ISI Web of Knowledge. Methods: The ISI Web of Knowledge was searched for articles on OCT published between 1982 and February 2012 using appropriate terms. Articles were characterized each year by publication type. Results: Search yielded 154 publications after the search for keywords “optical coherence tomography and multiple sclerosis and 167 publications after the search for the ...

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    6. Optical Coherence Tomography Features of POEMS Syndrome and Castleman Disease-associated Papillopathy

      Optical Coherence Tomography Features of POEMS Syndrome and Castleman Disease-associated Papillopathy

      Purpose : To report ocular symptoms and optical coherence tomography (OCT) features of polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes (POEMS) syndrome. Methods : Case report of two Caucasian patients with POEMS, one of whom also had multicentric Castleman disease. Results : Both patients presented with edema on both optic disks, bilateral macular edema was seen in case 1, and peripapillary choroidal neovascularization was seen on the right side in case 2. OCT confirmed papilledema involving all retinal layers, with additional bilateral peripapillary serous retinal detachment involving the macula in both cases, and peripapillary CNV in case 2. Changes in retinal nerve ...

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    7. Evaluation of mouse experimental autoimmune uveoretinitis by spectral domain optical coherence tomography

      Evaluation of mouse experimental autoimmune uveoretinitis by spectral domain optical coherence tomography

      Aims To evaluate the efficacy of spectral domain optical coherence tomography (SD-OCT) in monitoring the development of mouse experimental autoimmune uveoretinitis (EAU) as an animal model of endogenous uveitis, and to develop an OCT-based grading system for EAU severity. Methods C57BL/6 mice were immunised with human interphotoreceptor retinoid-binding protein (amino acid sequence 1–20) peptide and complete Freund's adjuvant to induce EAU. The development of EAU was monitored by SD-OCT serially throughout the disease course, and the images were graded from 1 to 4 and compared with the clinical and histopathological grades. Results SD-OCT images depicted retinal lamella ...

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    8. Enhanced depth imaging optical coherence tomography of the choroid in migraine patients: implications for the association of migraine and glaucoma

      Enhanced depth imaging optical coherence tomography of the choroid in migraine patients: implications for the association of migraine and glaucoma

      Aim To compare the choroidal thickness measurements obtained during the attack period and during the pain-free interval in migraine patients using enhanced depth imaging optical coherence tomography (OCT). Methods 58 eyes of 29 subjects with a diagnosis of migraine with or without aura were enrolled in this observational, cross-sectional study. Two OCT scans were performed for each patient, one during the peak period of the migraine attack and the other during the headache-free interval, using the enhanced depth imaging mode. Choroidal thicknesses were measured at the fovea, at three locations nasal and at three locations temporal to the fovea at ...

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    9. Postdoc Job Position at Doheny Eye Institute of University of California, Los Angeles

      Postdoc Job Position at Doheny Eye Institute of University of California, Los Angeles

      RESEARCH FIELDS: Anterior chamber image segmentation, analysis, and visualization RESEARCH LABORATORY: Doheny Image Analysis Laboratory (DIAL) at Doheny Eye Institute of University of California, Los Angeles PROJECT DESCRIPTION: We are a rapidly growing and interdisciplinary group to investigate new approaches for image segmentation, registration, visualization, and analysis in various multimodal ophthalmic images at Doheny Eye Institute, standing among the top recipients of medical research grants from the National Institutes of Health, which fund 80% of all vision research in America. This project is funded from our pharmaceutical sponsor, a well-established multi-specialty health care company. We are particularly interested in the ...

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    10. Spectral-domain optical coherence tomography findings of subinternal limiting membrane hemorrhage in the macula before and after Nd:YAG laser treatment

      Spectral-domain optical coherence tomography findings of subinternal limiting membrane hemorrhage in the macula before and after Nd:YAG laser treatment

      We reported the spectral-domain optical coherence tomography (SD-OCT) findings of a subinternal limiting membrane hemorrhage in the macula in one patient with Valsalva retinopathy and in one patient with macroaneurysm before and after neodymium-doped yttrium aluminum garnet (Nd:YAG) laser membranotomy. Within 1 week, the Nd:YAG laser treatment facilitated rapid absorption of the hemorrhage in both patients. Spectral-domain optical coherence tomography was helpful before laser treatment to evaluate the exact location of the blood and after laser treatment to confirm the amount and location of residual hemorrhage, which was hard to confirm by only indirect ophthalmoscopy.

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    11. The influence of axial length on confocal scanning laser ophthalmoscopy and spectral-domain optical coherence tomography size measurements: a pilot study

      The influence of axial length on confocal scanning laser ophthalmoscopy and spectral-domain optical coherence tomography size measurements: a pilot study

      Purpose To investigate the influence of axial length on SD-OCT and cSLO size measurements from the Heidelberg Spectralis. Methods In this pilot study, eight emmetropic pseudophakic eyes with subretinal visual implant were selected. 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. The known size of subretinal implant sensor field (2800 × 2800 μm) was measured on 15 images per eye with cSLO and SD-OCT. Results The mean axial length was 20.8 ± 0.8 mm in short eyes, 23.3 ± 0.4 mm in ...

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    12. Pathology detection rate of spectral domain optical coherence tomography devices

      Pathology detection rate of spectral domain optical coherence tomography devices

      Background Spectral domain optical coherence tomography (SDOCT) allows for higher resolution scans and higher scanning speeds compared to time domain OCT (TDOCT). The purpose of this study is to compare the pathology detection rates of various SDOCT devices to the Stratus TDOCT. Methods Patients with neovascular age-related macular degeneration were imaged on the Stratus and one of four SDOCT devices. The images were then analysed in a masked manner evaluating for the presence of epiretinal membrane (ERM), pigment epithelial detachment (PED) and subretinal fluid (SRF). After determining that low scan density with one of the devices was likely the cause ...

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    13. How hardware, software advances expand OCT capabilities

      How hardware, software advances expand OCT capabilities

      Progress in posterior segment optical coherence tomography (OCT) imaging is continuing with novel software that provides better correction for eye motion, as well as new technology which offers faster imaging speeds, said James Fujimoto, PhD. These developments will enable advanced processing and quantitative assessment of three-dimensional OCT data that—in the not-too-distant future—will bring functional imaging of blood flow and vascular structure into the hands of clinicians, said Dr. Fujimoto, professor of electrical engineering and computer science, Massachusetts Institute of Technology, Cambridge, MA. “We are now approaching a point with OCT where ophthalmologists have a view of the retina ...

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    14. High-resolution spectral domain-optical coherence tomography in multiple sclerosis, Part II – the total macular volume. The first follow-up study over 2 years

      High-resolution spectral domain-optical coherence tomography in multiple sclerosis, Part II – the total macular volume. The first follow-up study over 2 years

      Background: Recent studies investigating the use of optical coherence tomography (OCT) in multiple sclerosis (MS) patients have resulted in wide-ranging and often contradictory outcomes. This is mainly due to the complex etiology and heterogeneity of MS, physiological variations in the retinal nerve fiber layer (RNFL) and/or total macular volume (TMV), and limitations in methodology. It remains to be discovered whether any retinal changes in MS develop continuously or in a stepwise fashion, and whether these changes occur in all or a subset of patients. High-resolution spectral domain-OCT devices (SD-OCT) would be required to detect subtle retinal changes and longitudinal ...

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    15. A novel method of multi-parameter measurements for the mouse retina in vivo using optical coherence tomography

      A novel method of multi-parameter measurements for the mouse retina in vivo using optical coherence tomography

      Optical coherence tomography (OCT) is widely used in clinical diagnosis and is becoming more important for the evaluation of the mouse retinal structure in vivo. This study describes a novel method of multi-parameter measurements for the mouse retina using clinical OCT. Two lenses were adapted to the OCT optical system, and high-resolution, wide-angle retinal tomographic images were easily acquired with our method. The magnifications of this OCT optical system for mouse retinal images were quantified. The magnification in the transverse direction is 4.46, whereas the axial direction is barely magnified. With this method, the data of mouse retinal thickness ...

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    16. Spectral- and time-domain optical coherence tomography measurements of macular thickness in young myopic eyes

      Spectral- and time-domain optical coherence tomography measurements of macular thickness in young myopic eyes

      Purpose: To evaluate the variation in macular retinal thickness and volume in young Chinese myopic patients using time-domain optical coherence tomography (Stratus TD-OCT) and spectral-domain optical coherence tomography (Cirrus HD-OCT). Methods Ninety-two eyes of 92 myopic subjects were recruited in this study. Based upon spherical equivalence (SE), subjects were divided into two groups: the low to moderate myopia group (-0.5 D <= SE < -6.0 D), and the high myopia group (SE >= -6.0 D). Stratus TD-OCT and Cirrus HD-OCT were used to compare macular retinal thickness and volume between the two groups. Bland-Altman analysis and Pearson correlation were used ...

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    17. Comparison of Dynamic Changes in Anterior Ocular Structures Examined with Anterior Segment Optical Coherence Tomography in a Cohort of Various Origins

      Comparison of Dynamic Changes in Anterior Ocular Structures Examined with Anterior Segment Optical Coherence Tomography in a Cohort of Various Origins

      Purpose: To identify risk factors for angle closure from iris and angle anterior segment optical coherence tomography (ASOCT) measurements and to determine if these differ by geographic origin. Methods: ASOCT images from 267 clinic-based persons were compared between bright and dark conditions. An automated program quantified angle and iris parameters. Results: Iris area in bright light was larger with increasing age (univariate regression, p=0.0005), and largest in European and African-derived and smallest in Korean and Chinese eyes (multivariable regression, p=0.0001). Iris area was significantly larger in AC groups compared to normal and open angle glaucoma groups ...

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    18. Evaluation of graft-host interface after penetrating keratoplasty using anterior segment optical coherence tomography

      Evaluation of graft-host interface after penetrating keratoplasty using anterior segment optical coherence tomography

      PURPOSE: To evaluate the characteristics of the graft-host interface after penetrating keratoplasty (PKP) using anterior segment optical coherence tomography (AS-OCT). METHODS: Forty-nine eyes of 49 patients with three different underlying diseases (corneal scar, 22 eyes; bullous keratopathy, 14 eyes; keratoconus, 13 eyes) who underwent PKP were retrospectively reviewed. AS-OCT was performed in all patients and wound profiles of the graft-host junctions were classified into well-apposed junction, gap, step, and protrusion. The correlations between clinical characteristics and wound profiles from the AS-OCT were analyzed. RESULTS: A total of 392 graft-host junctions from 49 eyes were analyzed. Among them, 155 sections (39 ...

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    19. Method For Measuring An Eye

      Method For Measuring An Eye

      A method for measuring the axial length of an eye using optical coherence tomography, during which a plurality of A-scans of the OCT measurement are combined to an axial length, taking into account the alignment with which they were obtained, and taking into account the topography of the cornea. The distance of the front of the cornea from the retina is determined using OCT while measuring or controlling the alignment of the measuring device to the eye in that the topography of the front of the cornea is measured or made available. The calculation of an axial length from an ...

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    20. Optical coherence contrast imaging using gold nanorods in living mice eyes

      Optical coherence contrast imaging using gold nanorods in living mice eyes

      Background Optical Coherence Tomography (OCT) is a powerful imaging modality to visualize tissue structures, with axial image pixel resolution as high as 1.6 um in tissue. However, OCT is intrinsically limited to providing structural information as the OCT contrast is produced by optically scattering tissues. Methods Here we demonstrate gold nanorods (GNRs) injected into the anterior chamber (AC) and cornea of mice eyes can create a significant OCT signal and hence can be used as a contrast agent for in vivo OCT imaging. Results We show that a low dose of 30 nM of GNRs (13 nm in diameter ...

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    21. Parry-Romberg Syndrome Studied by Spectral-Domain Optical Coherence Tomography

      Parry-Romberg Syndrome Studied by Spectral-Domain Optical Coherence Tomography

      ABSTRACT ARTICLE FIGURES/TABLES REFERENCES Parry-Romberg syndrome is a rare disorder characterized by progressive hemifacial atrophy. Ophthalmic findings are characterized by enophthalmos, strabismus, nerve palsies, anisometropia, glaucoma, and angle abnormalities. Vision loss has also been reported due to retinal changes such as venous dilatation, disc edema, retinal edema, and retinal folds. The authors describe a case of Parry-Romberg syndrome with retinal alterations but a normal macula on spectral-domain optical coherence tomography.

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    22. Spectralis OCT Atlas launched by Heidelberg Engineering

      Spectralis OCT Atlas launched by Heidelberg Engineering

      Extensive images and clear labelling feature in a new Optical Coherence Tomography Atlas, specifically for users of the advanced scanning provided by Heidelberg Engineering’s SPECTRALIS OCT. Designed to help educate SPECTRALIS users in the interpretation of OCT imaging and the evaluation of various disease states, it has been produced for Heidelberg Engineering by Washington-based Consultant Vitreo Retinal Surgeon, Neal Adams. As Editor-in-Chief of the Peer Reviewed EYE REPORT, Neal has ensured great clarity of presentation to make this an easy electronic reference tool. “This is not a diagnostic guide, and no substitute for clinical experience and judgement, but a ...

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    23. Macular hole formation and spontaneous closure after vitrectomy for vitreomacular traction documented in spectral-domain optical coherence tomography

      Macular hole formation and spontaneous closure after vitrectomy for vitreomacular traction documented in spectral-domain optical coherence tomography

      Background We present a case of a macular hole formation and its spontaneous closure after vitrectomy for vitreomacular traction. To our knowledge, it is the first description of spontaneous closure of the macular hole after vitrectomy for vitreomacular traction. Case presentation A 78-year-old woman presented decreased visual acuity and metamorphopsia in the right eye due to vitreomacular traction. A vitrectomy with internal limiting membrane peeling and an air tamponade was performed in the right eye. Spectral-domain optical coherence tomography was obtained during all visits. Seven days after the vitrectomy, the spectral-domain optical coherence tomography showed a resolved vitreomacular traction and ...

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