1. Articles in category: Ophthalmology

    1-24 of 9568 1 2 3 4 ... 397 398 399 »
    1. Automatic vessel detection by means of brightness profile characterization in OCT images

      Automatic vessel detection by means of brightness profile characterization in OCT images

      Optical Coherence Tomography (OCT) is a well-established medical imaging technique that allows the analysis of the eye fundus characteristics in real time. These images enable the experts to make a clinical evaluation of the retinal vasculature, whose morphology provides relevant information for diseases like diabetes, hypertension or arteriosclerosis. In this paper, we present a novel proposal for the automatic vasculature identification in retinal OCT images. To achieve this, we analyse the intensity profiles between representative retinal layers, previously segmented. Then, two statistical models are generated using representative samples of vessel and non-vessel profiles. The analysis of both statistical models let ...

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    2. A COMPARATIVE STUDY OF CENTRAL FOVEAL THICKNESS PRE AND POST CATARACT SURGERY USING SD-OPTICAL COHERENCE TOMOGRAPHY

      A COMPARATIVE STUDY OF CENTRAL FOVEAL THICKNESS PRE AND POST CATARACT SURGERY USING SD-OPTICAL COHERENCE TOMOGRAPHY

      BACKGROUND The purpose of this study is to compare central foveal thickness (CFT) of patients preoperatively and postoperatively cataract surgery using SD- optical coherence tomography and to correlate CFT with vision. MATERIALS AND METHODS 200 eyes of 100 patients were examined and two groups were formed. Group-A was considered as the control group in the study and eyes in group-B were operated for cataract using SICS technique. The central foveal thickness (CFT) in each group was measured using SD-OCT machine (Cirrus Zeiss) preoperatively, postoperatively on day 1, week 1 and after 1 month and the data was compiled and compared ...

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    3. Optical coherence tomography findings and successful repair of retina detachment in Knobloch syndrome

      A 7-year-old Afghani girl was referred to the retina clinic of Massachusetts Eye and Ear for a chronic-appearing, macula-off retinal detachment in the left eye. On examination, best-corrected visual acuity was 20/400 in the right eye and 20/800 in the left eye. She had bilateral horizontal nystagmus. Ophthalmoscopy revealed prominent choroidal vessels, chorioretinal atrophy in the macular area, attenuated retinal vasculature, and pale optic discs bilaterally. Spectral domain optical coherence tomography demonstrated atrophy of the choriocapillaris and the retinal pigment epithelium, retinal thinning, and abnormal foveal contour. In the right eye, findings were reminiscent of dome shape maculopathy ...

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    4. Feature definition, analysis and selection for cystoid region characterization in Optical Coherence Tomography

      Feature definition, analysis and selection for cystoid region characterization in Optical Coherence Tomography

      Optical Coherence Tomography (OCT) is, nowadays, a clinical standard imaging technique in opthalmology as it provides more information than other classical modalities as can be, for instance, retinographies. OCT scans show a 3D representation of the real layout of the eye fundus in a non-invasive way, letting clinicians inspect deeply the retinal layers in a cross-sectional visualization. For that reason, OCT scans are commonly used in the study of the retinal morphology and the identification of pathological structures. Among them, an appropriate identification and analysis of any present intraretinal cystoid region is crucial to perform an adequate diagnosis of the ...

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    5. Cystoid macular edema segmentation of Optical Coherence Tomography images using fully convolutional neural networks and fully connected CRFs

      Cystoid macular edema segmentation of Optical Coherence Tomography images using fully convolutional neural networks and fully connected CRFs

      In this paper we present a new method for cystoid macular edema (CME) segmentation in retinal Optical Coherence Tomography (OCT) images, using a fully convolutional neural network (FCN) and a fully connected conditional random fields (dense CRFs). As a first step, the framework trains the FCN model to extract features from retinal layers in OCT images, which exhibit CME, and then segments CME regions using the trained model. Thereafter, dense CRFs are used to refine the segmentation according to the edema appearance. We have trained and tested the framework with OCT images from 10 patients with diabetic macular edema (DME ...

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    6. Quantitative optical coherence tomography angiography of macular vascular structure and foveal avascular zone in glaucoma

      Quantitative optical coherence tomography angiography of macular vascular structure and foveal avascular zone in glaucoma

      Objective The study aimed to evaluate the quantitative characteristics of the macular vessel density (VD) and foveal avascular zone (FAZ) in glaucoma using optical coherence tomography angiography (OCT-A). Design Cross-sectional, age- and sex-matched case–control study. Methods Fifty-two eyes of 52 patients with primary open angle glaucoma and 52 eyes from 52 healthy participants were recruited retrospectively. OCT-A was performed on a 3 x 3-mm macular region centered on the fovea. OCT-A scans were manually graded to define the FAZ. Parafoveal VD in superficial and deep retina were analyzed in the circular- and quadrant-segmented zone. The FAZ parameters included size ...

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    7. Choroidal Variations in Diabetic Macular Edema: Fluorescein Angiography and Optical Coherence Tomography

      Choroidal Variations in Diabetic Macular Edema: Fluorescein Angiography and Optical Coherence Tomography

      Purposes : To (i) evaluate variations in choroidal thickness (CT) and choroidal volume (CV) in diabetic macular edema (DME), as demonstrated by fluorescein angiography (FA) and enhanced depth-imaging (EDI) optical coherence tomography (OCT) (EDI-OCT) and (ii) correlate these variations with visual acuity. Methods : This study was a retrospective observational case series of patients with diabetic retinopathy (DR) and DME. The study groups comprised 77 DR patients ( n = 87), all of whom underwent color fundus photography, FA, and OCT on the same day. The control group comprised 25 age-matched healthy individuals ( n = 50 eyes). CT was measured by manual segmentation (EDI-OCT built-in ...

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    8. Optical coherence tomography angiography retinal vascular network assessment in multiple sclerosis

      Optical coherence tomography angiography retinal vascular network assessment in multiple sclerosis

      Background: Optical coherence tomography (OCT) angiography is a new method to assess the density of the vascular networks. Vascular abnormalities are considered involved in multiple sclerosis (MS) pathology. Objective: To assess the presence of vascular abnormalities in MS and to evaluate their correlation to disease features. Methods: A total of 50 MS patients with and without history of optic neuritis (ON) and 46 healthy subjects were included. All underwent spectral domain (SD)-OCT and OCT angiography. Clinical history, Expanded Disability Status Scale (EDSS), Multiple Sclerosis Severity Score (MSSS) and disease duration were collected. Results: Angio-OCT showed a vessel density reduction ...

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    9. Multi-Modal Imaging Including Optical Coherence Tomography Angiography in Patients With Posterior Multifocal Placoid Pigment Epitheliopathy

      Multi-Modal Imaging Including Optical Coherence Tomography Angiography in Patients With Posterior Multifocal Placoid Pigment Epitheliopathy

      ACKGROUND AND OBJECTIVE: New imaging methods provide novel insights into the pathogenesis of acute posterior multifocal placoid pigment epitheliopathy (APMPPE). PATIENTS AND METHODS: Four patients (eight eyes) in acute, subacute, and late phases of the disease were analyzed with multi-modal imaging methods including optical coherence tomography angiography (OCTA), structural OCT, fundus photography, and fundus autofluorescence. One patient was observed during the entire disease course. RESULTS: In acute and subacute phases of the disease, an early blockage in fluorescein angiography was found. OCTA showed perfusion defects in choriocapillaris and choroid slabs. During the course of disease, perfusion deficits observed in OCTA ...

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    10. Simultaneous OCT and B-FAF in Eyes With Alteration of the Foveal Contour

      Simultaneous OCT and B-FAF in Eyes With Alteration of the Foveal Contour

      Some alterations of the foveal contour do not meet the criteria established for the definition of lamellar macular hole on the basis of optical coherence tomography (OCT). However, these alterations may show an appearance, on blue fundus autofluorescence (B-FAF) imaging, reminiscent of lamellar macular hole. The aim of the study is to evaluate in detail these alterations recording simultaneously OCT and B-FAF.

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    11. Evaluation of retinal nerve fibre layer, ganglion cell layer and choroidal thickness with optical coherence tomography in migraine patients: a case-control study

      Evaluation of retinal nerve fibre layer, ganglion cell layer and choroidal thickness with optical coherence tomography in migraine patients: a case-control study

      Background Evaluation of retinal nerve fibre layer (RNFL), ganglion cell layer (GCL) and choroidal thickness (CT) with optical coherence tomography (OCT) in chronic migraine patients, to compare with healthy controls. Material and Method Ninety-four eyes of 47 chronic migraine patients (Group 1) and 68 eyes of 34 healthy individuals (Group 2) were included in this prospective case-control study. The right and left eyes were separately evaluated. Mean peripapillary RNFL thicknesses, mean GCL measured from superior and inferior quadrants, and mean CT were measured at three different regions (central, 500 μm nasal and temporal region of the fovea). Results There was ...

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    12. Optical Coherence Tomography Angiography to Better understand Glaucoma

      Optical Coherence Tomography Angiography to Better understand Glaucoma

      The term optical coherence tomography angiography (OCTA) comprises different OCT-based technologies which all allow noninvasive assessment of retinal perfusion, based on moving red blood cells. The main areas where OCTA is currently used are investigation of perfusion and vascular structure of the macular retina (e.g., in macular degenerations and diabetic macular diseases) and the disk and peripapillary retina (in glaucoma and other optic disk diseases). The current editorial provides a brief overview on the potential of OCTA and its use to measure perfusion in the peripapillary retina in glaucoma.

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    13. Clinical relevance of retinal structure in children with laser-treated retinopathy of prematurity versus controls – using optical coherence tomography

      Clinical relevance of retinal structure in children with laser-treated retinopathy of prematurity versus controls – using optical coherence tomography

      Purpose We aimed to assess the macular anatomy using spectral domain optical coherence tomography (SD-OCT), in children born preterm who had laser-treated retinopathy of prematurity (ROP), and to investigate the relationship between structural changes in macula and visual function. Methods Thirty-seven 3–8 years old children were included in the study in two groups: 20 children born preterm [(<34 weeks of gestation, birthweight (BW) <2000 g)] who had laser-treated ROP in the Neonatology Department, Municipal Clinical Emergency Hospital of Timisoara, Romania; and 17 controls (children born at term, without eye disease, matched for age and gender). Spectral domain optical coherence ...

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    14. Stanford University Receives NIH Grant for Imaging Structure and Function

      Stanford University Receives NIH Grant for Imaging Structure and Function

      Stanford University Receives a 2017 NIH Grant for $139,730 for Imaging Structure and Function. The principal investigator is Thomas Clandinin. The program began in 2017 and ends in 2018. Below is a summary of the proposed work. Imaging technologies such as confocal microscopy, multiphoton microscopy and super- resolution imaging as well as optical coherence tomography have transformed the ability of scientists to observe structural and functional changes in the visual system, in vivo and ex vivo, in both health and disease. The overarching goal of the imaging core is to transform the ability of vision scientists to use these ...

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    15. Optical Coherence Tomography Evolution in a Case of X-Linked Juvenile Retinoschisis: 15 Years of Follow-Up

      Optical Coherence Tomography Evolution in a Case of X-Linked Juvenile Retinoschisis: 15 Years of Follow-Up

      Purpose: We present the evolution of X-linked juvenile retinoschisis (XLRS) in a male patient using optical coherence tomography (OCT) with a long-term follow-up time of 15 years. Case Description: A 10-year-old male patient presented at the Medical Retina Department of our hospital complaining for blurred vision in both eyes. At the initial presentation in 2001, his best corrected visual acuity (BCVA) was 6/12 in both eyes on the Snellen chart. Based on clinical and OCT findings, the diagnosis of XLRS was made, and it was confirmed by genetic testing. No treatment was performed, but the patient was regularly examined ...

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    16. CNNs Enable Accurate and Fast Segmentation of Drusen in Optical Coherence Tomography

      CNNs Enable Accurate and Fast Segmentation of Drusen in Optical Coherence Tomography

      Optical coherence tomography (OCT) is used to diagnose and track progression of age-related macular degeneration (AMD). Drusen, which appear as bumps between Bruch’s membrane (BM) and the retinal pigment epithelium (RPE) layer, are among the most important biomarkers for staging AMD. In this work, we develop and compare three automated methods for Drusen segmentation based on the U-Net convolutional neural network architecture. By cross-validating on more than 50, 000 annotated images, we demonstrate that all three approaches achieve much better accuracy than a current state-of-the-art method. Highest accuracy is achieved when the CNN is trained to segment the BM ...

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    17. Repeatability and Reproducibility of Superficial Macular Retinal Vessel Density Measurements Using Optical Coherence Tomography Angiography En Face Images

      Repeatability and Reproducibility of Superficial Macular Retinal Vessel Density Measurements Using Optical Coherence Tomography Angiography En Face Images

      Importance The repeatability and reproducibility of quantitative metrics from optical coherence tomographic angiography (OCTA) must be assessed before these data can be confidently interpreted in clinical research and practice. Objective To evaluate the repeatability and reproducibility of OCTA-derived retinal vascular quantitative metrics. Design, Setting and Participants In this cross-sectional study, 21 healthy volunteers (42 eyes) and 22 patients with retinal disease (22 eyes), including 14 with age-related macular degeneration, 3 with epiretinal membrane, 2 with diabetic retinopathy, 2 with myopic macular degeneration, and 1 with retinal vein occlusion, were enrolled. Participants were recruited from September 1 through November 31, 2016 ...

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    18. Macular retinal and choroidal thickness in unilateral amblyopia using swept-source optical coherence tomography

      Macular retinal and choroidal thickness in unilateral amblyopia using swept-source optical coherence tomography

      Background To investigate macular retinal and choroidal thickness in amblyopic eyes compared to that in fellow and normal eyes using swept-source optical coherence tomography (SS-OCT). Methods This study examined 31 patients with hyperopic anisometropic amblyopia (6.9 ± 3.8 years, mean ± standard deviation), 15 patients with strabismic amblyopia without anisometropia (7.9 ± 4.2 years), and 24 age-matched controls (7.8 ± 3.3 years). Retinal and choroidal thickness was measured by 3D scans using SS-OCT. A 6-mm area around the fovea was automatically analyzed using the Early Treatment Diabetic Retinopathy Study map. The thickness from SS-OCT was corrected for magnification ...

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    19. Optical coherence tomography angiography in glaucoma: a mini-review

      Optical coherence tomography angiography in glaucoma: a mini-review

      The advent of optical coherence tomography angiography (OCT-A) provides a new opportunity to visualize the retinal vasculature in a non-invasive and dye-free manner which may help identify vascular abnormalities in glaucoma. While a reduction in retinal and optic nerve head vessel densities and blood flow indexes measured by OCT-A has been demonstrated in patients with glaucoma in many studies, it is unclear whether OCT-A provides additional information for the detection and monitoring of glaucoma compared with OCT measurements such as retinal nerve fiber layer thickness, neuroretinal rim width, and ganglion cell inner plexiform layer thickness. Longitudinal studies are needed to ...

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    20. Re: Kwon et al.: Subclassification of primary angle closure using anterior segment optical coherence tomography and ultrasound biomicroscopic parameters (Ophthalmology. 2017;124:1039-1047)

      Re: Kwon et al.: Subclassification of primary angle closure using anterior segment optical coherence tomography and ultrasound biomicroscopic parameters (Ophthalmology. 2017;124:1039-1047)

      To the Editor: We read with interest the article by Sung et al. 1 In this observational study, the authors concluded that the most distinct difference between the 2 subgroups in the cluster analysis was trabecular–ciliary process angle (TCA) and that the position of the ciliary body is important in subclassifying primary angle closure. However, there are several limitations that may affect the results. First, in the study, the authors reported that gonioscopy and image analysis using ImageJ was all conducted by a single researcher. These 2 measurements, however, both can be influenced by observers' subjectivity. To reduce influence ...

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    21. Intraoperative Optical Coherence Tomography of Internal Limiting Membrane Flap

      Intraoperative Optical Coherence Tomography of Internal Limiting Membrane Flap

      A 66-year-old woman with a 450-μm diameter macular hole (MH) in her right eye underwent vitrectomy, internal limiting membrane (ILM) peel with inverted ILM flap, and perfluoropropane (C3F8) gas tamponade. Inverted ILM flaps may improve outcomes for holes larger than 400 μm; however, confirming proper ILM placement is difficult after air-fluid exchange.

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    22. Cilioretinal Artery Imaged with Optical Coherence Tomography Angiography

      Cilioretinal Artery Imaged with Optical Coherence Tomography Angiography

      A 48-year-old woman presented with peripapillary chorioretinal atrophy and cilioretinal artery in the left eye without other findings (Fig 1A). Optical coherence tomography angiography (OCTA) through full-thickness retinal segmentation (Fig 1B) showed intact retinal perfusion. The cilioretinal artery arose from the temporal margin of the optic nerve and coursed into the retina, resembling a hook.

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    23. Optical coherence tomography angiography in pituitary tumor

      Optical coherence tomography angiography in pituitary tumor

      A 32-year-old man with a pituitary tumor had bitemporal hemianopia (figure 1). Peripapillary retinal nerve fiber layer (RNFL) in optical coherence tomography (OCT) was reduced, which corresponded to visual field defects. OCT angiography showed a dropout of capillaries and correlated well with RNFL loss in the OCT (figure 2). Compressive optic neuropathy may be associated with loss of the retinal ganglion cell layer and impaired peripapillary retinal perfusion. OCT angiography may be helpful to detect various optic neuropathies and in analyzing the vascular status of the optic nerve head and RNFL.1

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