1. Articles in category: Ophthalmology

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    1. Columbia University Receives NIH Grant for Elastographic Imaging of the Retina/Choroid in Age-Related Macular Degeneration

      Columbia University Receives NIH Grant for Elastographic Imaging of the Retina/Choroid in Age-Related Macular Degeneration

      Columbia University Receives a 2015 NIH Grant for $281,840 for Elastographic Imaging of the Retina/Choroid in Age-Related Macular Degeneration. The principal investigator is Ronald Silverman. The program began in 2012 and ends in 2016. Below is a summary of the proposed work. Age-related macular degeneration (AMD) is a disease of the retinal pigment epithelium characterized by the appearance of protein/lipid deposits (drusen), geographic atrophy and neovascularization. Techniques currently used for diagnostic imaging of AMD include indocyanine green dye or fluorescein angiography, autofluorescence imaging and optical coherence tomography (OCT). OCT images depict optical backscatter, caused by variation in ...

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    2. Comparison of the current and a new RTVue OCT software version for detection of ganglion cell complex changes due to cataract surgery

      Comparison of the current and a new RTVue OCT software version for detection of ganglion cell complex changes due to cataract surgery

      The purpose was to compare the current (6.3) and a novel software version (6.12) of the RTVue-100 optical coherence tomograph (RTVue OCT) for ganglion cell complex (GCC) and retinal nerve fibre layer thickness (RNFLT) changes after phacoemulsification in healthy cataract eyes, and to investigate whether version 6.12, in which image segmentation is improved, provides benefits over version 6.3 for RNFLT and GCC imaging via mild cataract. One eye of 22 consecutive healthy cataract patients were imaged before and 1 month after uncomplicated cataract surgery using RTVue-100 OCT software version 6.3. The images were analysed with ...

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    3. Enhancing the visualization of human retina vascular networks by Graphics Processing Unit accelerated speckle variance OCT and graph cut retinal layer segmentation

      Enhancing the visualization of human retina vascular networks by Graphics Processing Unit accelerated speckle variance OCT and graph cut retinal layer segmentation

      We present a Graph Cut based image segmentation that was implemented on a Graphics Processing Unit for acceleration of processing retinal images acquired with OCT. We applied this work to generate a retinal thickness map, and for retinal layer segmentation to enhance the visualization of vasculature networks from distinct retinal capillary beds during acquisition using speckle variance OCT.

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    4. Evaluation of choroidal thickness using enhanced depth imaging by spectral-domain optical coherence tomography in patients with pseudoexfoliation syndrome

      Evaluation of choroidal thickness using enhanced depth imaging by spectral-domain optical coherence tomography in patients with pseudoexfoliation syndrome

      Purpose To investigate the choroidal thickness using optical coherence tomography in the eyes of patients with unilateral and bilateral pseudoexfoliation syndrome and to compare them with healthy controls. Methods We studied four groups: (1) affected eyes from 30 patients with unilateral PEX syndrome affecting the right eye of 17 patients and the left eye of 13 patients; (2) clinically unaffected eyes of 30 patients with unilateral PEX syndrome; (3) the eyes of 30 patients with bilateral PEX syndrome; and (4) the eyes of 30 normal healthy subjects. Choroidal thickness was evaluated using high-speed, high-resolution enhanced depth imaging by spectral-domain optical ...

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    5. Clinical Applications of Anterior Segment Optical Coherence Tomography

      Clinical Applications of Anterior Segment Optical Coherence Tomography

      Anterior segment optical coherence tomography (AS-OCT) was recently developed and has become a crucial tool in clinical practice. AS-OCT is a noncontact imaging device that provides the detailed structure of the anterior part of the eyes. In this review, the author will discuss the various clinical applications of AS-OCT, such as the normal findings, tear meniscus measurement, ocular surface disease (e.g., pterygium, pinguecula, and scleromalacia), architectural analysis after cataract surgery, post-LASIK keratectasia, Descemet’s membrane detachment, evaluation of corneal graft after keratoplasty, corneal deposits (corneal dystrophies and corneal verticillata), keratitis, anterior segment tumors, and glaucoma evaluation (angle assessment, morphological ...

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    6. Spectral domain optical coherence tomography imaging of tubercular chorioretinitis and intraretinal granuloma. Intraretinal tuberculosis: a case report

      Spectral domain optical coherence tomography imaging of tubercular chorioretinitis and intraretinal granuloma. Intraretinal tuberculosis: a case report

      The aim of this study is to report the clinical and spectral domain optical coherence tomography (SD-OCT) findings in a patient suffering from ulcerative colitis with bilateral tubercular chorioretinitis and intraretinal granuloma regressed with systemic antitubercular therapy (ATT). This study is a case report of a 33-year-old Bangladeshi male with ulcerative colitis treated with oral corticosteroids and azathioprine who was referred to our department with a diagnosis of central serous chorioretinopathy. Serological tests, the Mantoux skin test, complete ophthalmologic examination, ocular fundus photography, fundus fluorescein angiography, and SD-OCT scans were performed. The ophthalmological inflammatory pattern and serological investigations provided an ...

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    7. The Project MACULA retinal pigment epithelium grading system for histology and optical coherence tomography in age-related macular degeneration

      The Project MACULA retinal pigment epithelium grading system for histology and optical coherence tomography in age-related macular degeneration

      Purpose: To seek pathways of retinal pigment epithelium (RPE) fate in age-related macular degeneration via a morphology grading system ; provide nomenclature, visualization targets, and metrics for cl in ical imag in g and model system s. Methods: Donor eyes with geographic atrophy (GA) or choroidal neovascularization (CNV) and one GA eye with previous cl in ical spectral doma in optical coherence tomography (SDOCT) imag in g were processed for histology , photodocumented, and annotated at pre-def in ed locations. RPE cells conta in ed sp in dle-shaped melanosomes, apposed a basal lam in a or basal lam in ar deposit (BLamD ...

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    8. Multimodal Imaging In Foveal Red Spot Syndrome

      Multimodal Imaging In Foveal Red Spot Syndrome

      Purpose: To describe multimodal imaging findings in a patient with foveal red spot syndrome. Methods: We report a case of a 57-year-old man with foveal red spot syndrome. Multimodal imaging techniques, including fundus color and red-free photographs, fluorescence angiography (Topcon 50DX; Topcon, Tokyo, Japan), MultiColor scanning laser imaging, spectral domain optical coherence tomography (Spectralis; Heidelberg Engineering, Heidelberg, Germany), swept source optical coherence tomography (DRI OCT-1 Atlantis; Topcon, Tokyo, Japan), adaptive optics (RTX-1; Imagine Eyes, Orsay, France), and microperimetry (MP1 Microperimeter; Nidek Technologies, Padua, Italy), were performed to confirm the diagnosis and determine the anatomical abnormalities related to the disease. Results ...

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    9. Tear Meniscus Evaluation Using Optical Coherence Tomography in Dry Eye Patients

      Tear Meniscus Evaluation Using Optical Coherence Tomography in Dry Eye Patients

      Purpose To evaluate the tear meniscus in aqueous tear-deficient dry eye patients using Fourier-domain optical coherence tomography (FD-OCT) and to investigate the clinical usefulness of tear meniscus values. Methods The present study included 79 aqueous tear-deficient dry eyes and 50 normal eyes. Tear meniscus height (TMH), tear meniscus depth (TMD), and tear meniscus area (TMA) were imaged using FD-OCT and measured with computer calipers. Schirmer's test, tear break-up time, and corneal fluorescein staining were also performed and the correlations between the tests were analyzed. Additionally, the diagnostic power of tear meniscus values was compared using area under the receiver ...

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    10. Automated age-related macular degeneration classification in OCT using unsupervised feature learning

      Automated age-related macular degeneration classification in OCT using unsupervised feature learning

      Age-related Macular Degeneration (AMD) is a common eye disorder with high prevalence in elderly people. The disease mainly affects the central part of the retina, and could ultimately lead to permanent vision loss. Optical Coherence Tomography (OCT) is becoming the standard imaging modality in diagnosis of AMD and the assessment of its progression. However, the evaluation of the obtained volumetric scan is time consuming, expensive and the signs of early AMD are easy to miss. In this paper we propose a classification method to automatically distinguish AMD patients from healthy subjects with high accuracy. The method is based on an ...

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    11. Imaging modal content of cone photoreceptors using adaptive optics optical coherence tomography

      Imaging modal content of cone photoreceptors using adaptive optics optical coherence tomography

      It has been long established that photoreceptors capture light based on the principles of optical waveguiding. Yet after decades of experimental and theoretical investigations considerable uncertainty remains, even for the most basic prediction as to whether photoreceptors support more than a single waveguide mode. To test for modal behavior in human cone photoreceptors, we took advantage of adaptive-optics optical coherence tomography (AO-OCT, λc=785 nm) to noninvasively image in three dimensions the reflectance profiles generated in the inner and outer segments (IS, OS) of cones. Mode content was examined over a range of cone diameters by imaging cones from 0 ...

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    12. Automated segmentation of serous pigment epithelium detachment in SD-OCT images

      Automated segmentation of serous pigment epithelium detachment in SD-OCT images

      Pigment epithelium detachment (PED) is an important clinical manifestation of multiple chorio-retinal disease processes, which can cause the loss of central vision. A 3-D method is proposed to automatically segment serous PED in SD-OCT images. The proposed method consists of five steps: first, a curvature anisotropic diffusion filter is applied to remove speckle noise. Second, the graph search method is applied for abnormal retinal layer segmentation associated with retinal pigment epithelium (RPE) deformation. During this process, Bruch’s membrane, which doesn’t show in the SD-OCT images, is estimated with the convex hull algorithm. Third, the foreground and background seeds ...

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    13. Longitudinal graph-based segmentation of macular OCT using fundus alignment

      Longitudinal graph-based segmentation of macular OCT using fundus alignment

      Segmentation of retinal layers in optical coherence tomography (OCT) has become an important diagnostic tool for a variety of ocular and neurological diseases. Currently all OCT segmentation algorithms analyze data independently, ignoring previous scans, which can lead to spurious measurements due to algorithm variability and failure to identify subtle changes in retinal layers. In this paper, we present a graph-based segmentation framework to provide consistent longitudinal segmentation results. Regularization over time is accomplished by adding weighted edges between corresponding voxels at each visit. We align the scans to a common subject space before connecting the graphs by registering the data ...

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    14. Fast and memory-efficient LOGISMOS graph search for intraretinal layer segmentation of 3D macular OCT scans

      Fast and memory-efficient LOGISMOS graph search for intraretinal layer segmentation of 3D macular OCT scans

      Image segmentation is important for quantitative analysis of medical image data. Recently, our research group has introduced a 3-D graph search method which can simultaneously segment optimal interacting surfaces with respect to the cost function in volumetric images. Although it provides excellent segmentation accuracy, it is computationally demanding (both CPU and memory) to simultaneously segment multiple surfaces from large volumetric images. Therefore, we propose a new, fast, and memory-efficient graph search method for intraretinal layer segmentation of 3-D macular optical coherence tomograpy (OCT) scans. The key idea is to reduce the size of a graph by combining the nodes with ...

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    15. Tchebichef moments based nonlocal-means method for despeckling optical coherence tomography images

      Tchebichef moments based nonlocal-means method for despeckling optical coherence tomography images

      Speckle reduction in optical coherence tomography (OCT) images plays an important role in further image analysis. Although numerous despeckling methods, such as the Kuan’s filter, the Frost’s filter, wavelet based methods, anisotropic diffusion methods, have been proposed for despeckling OCT images, these methods generally tend to provide insufficient speckle suppression or limited detail preservation especially at high speckle corruption because of the insufficient utilization of image information. Different from these denoising methods, the nonlocal means (NLM) method explores nonlocal image self-similarities for image denoising, thereby providing a new method for speckle reduction in OCT images. However, the NLM ...

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    16. Automated detection of Schlemm's canal in spectral-domain optical coherence tomography

      Automated detection of Schlemm's canal in spectral-domain optical coherence tomography

      Recent advances in optical coherence tomography (OCT) technology allow in vivo imaging of the complex network of intra-scleral aqueous veins in the anterior segment of the eye. Pathological changes in this network, draining the aqueous humor from the eye, are considered to play a role in intraocular pressure elevation, which can lead to glaucoma, one of the major causes of blindness in the world. Through acquisition of OCT volume scans of the anterior eye segment, we aim at reconstructing the three dimensional network of aqueous veins in healthy and glaucomatous subjects. A novel algorithm for segmentation of the three-dimensional (3D ...

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    17. Combined use of high-density and volumetric optical coherence tomography for the segmentation of neural canal opening in cases of optic nerve edema

      Combined use of high-density and volumetric optical coherence tomography for the segmentation of neural canal opening in cases of optic nerve edema

      In cases of optic-nerve-head edema, the presence of the swelling reduces the visibility of the underlying neural canal opening (NCO) within spectral-domain optical coherence tomography (SD-OCT) volumes. Consequently, traditional SD-OCT-based NCO segmentation methods often overestimate the size of the NCO. The visibility of the NCO can be improved using high-definition 2D raster scans, but such scans do not provide 3D contextual image information. In this work, we present a semi-automated approach for the segmentation of the NCO in cases of optic disc edema by combining image information from volumetric and high-definition raster SD-OCT image sequences. In particular, for each subject ...

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    18. Automated retinal fovea type distinction in spectral-domain optical coherence tomography of retinal vein occlusion

      Automated retinal fovea type distinction in spectral-domain optical coherence tomography of retinal vein occlusion

      Spectral-domain Optical Coherence Tomography (SD-OCT) is a non-invasive modality for acquiring high- resolution, three-dimensional (3D) cross-sectional volumetric images of the retina and the subretinal layers. SD-OCT also allows the detailed imaging of retinal pathology, aiding clinicians in the diagnosis of sight degrading diseases such as age-related macular degeneration (AMD), glaucoma and retinal vein occlusion (RVO). Disease diagnosis, assessment, and treatment will require a patient to undergo multiple OCT scans, possibly using multiple scanners, to accurately and precisely gauge disease activity, progression and treatment success. However, cross-vendor imaging and patient movement may result in poor scan spatial correlation potentially leading to ...

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    19. Can ganglion cell complex assessment on cirrus HD OCT aid in detection of early glaucoma?

      Can ganglion cell complex assessment on cirrus HD OCT aid in detection of early glaucoma?

      Context Ganglion cell complex is damaged early in glaucoma. Does this loss of GCC help in early diagnosis of glaucoma. Aims To compare the RNFL thickness and ganglion cell complex (GCC) in diagnosed patients of glaucoma, pre-perimetric glaucoma and normal controls. Settings and design Case controlled, observational study. Methods and material 33 glaucoma patients, 45 pre-perimetric glaucoma, and 30 controls were enrolled in the study. ONH parameters on cirrus HD OCT like CD ratio, para papillary RNFL thickness and GCC were calculated for each case. Statistical analysis used ANOVA test to analyse differences between groups. ROC for ganglion cell layer ...

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    20. Comparison of Physiologic versus Pharmacologic Mydriasis on Anterior Chamber Angle Measurements Using Spectral Domain Optical Coherence Tomography

      Comparison of Physiologic versus Pharmacologic Mydriasis on Anterior Chamber Angle Measurements Using Spectral Domain Optical Coherence Tomography

      Purpose. To compare the effects of physiologic versus pharmacologic pupil dilation on anterior chamber angle (ACA) measurements obtained with spectral domain optical coherence tomography (SD-OCT). Methods. Forty eyes from 20 healthy, phakic individuals with open angles underwent anterior segment OCT imaging under 3 pupillary states: (1) pupil constricted under standard room lighting, (2) physiologic mydriasis in a darkened room, and (3) postpharmacologic mydriasis. Inferior angle Schwalbe’s line-angle opening distance (SL-AOD) and SL-trabecular-iris-space area (SL-TISA) were computed for each eye and pupillary condition by masked, certified Reading Center graders using customized grading software. Results. SL-AOD and SL-TISA under pupillary constriction ...

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    21. Pars Plana Vitrectomy with Air Tamponade for Optic Disc Pit Maculopathy: Swept-source Optical Coherence Tomography Imaging Findings and Surgical Approach

      Pars Plana Vitrectomy with Air Tamponade for Optic Disc Pit Maculopathy: Swept-source Optical Coherence Tomography Imaging Findings and Surgical Approach

      Purpose: To describe how Swept Source Optical Coherence Tomography (SS-OCT) provides enhanced diagnostic information enabling optimisation of surgical strategy in a pediatric patient suffering from ODP maculopathy. We report the first case of successful management of ODP maculopathy via pars plana vitrectomy (PPV) and air tamponade. Methods: Interventional case report. Results: A five-year-old girl presented with ODP and serous macular detachment in her previously amblyopic left eye. SS-OCT showed optically opaque vitreous fibres perpendicularly attached to the base of the optic nerve head excavation and what appeared to be fibrous tissue at the base of the excavation of the optic ...

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    22. Applicability of the ISNT and IST rules on retinal nerve fiber layer measurement on spectral-domain optical coherence tomography in normal Indian children

      Applicability of the ISNT and IST rules on retinal nerve fiber layer measurement on spectral-domain optical coherence tomography in normal Indian children

      Background To determine the applicability of the ISNT (inferior>superior>nasal>temporal) and IST (inferior>superior>temporal) rules on retinal nerve fiber layer (RNFL) measurement on spectral-domain optical coherence tomography (SD-OCT) in normal children. Methods A prospective, cross-sectional study including consecutive subjects between the ages of 5–18 years who were born at term (≥37 weeks gestational age) and with a normal birth weight (≥2500 g) presenting to the out-patient department for refractive error examination. RNFL measurement was done on Spectralis SD-OCT. Exclusion criteria were best-corrected visual acuity less than 20/20, spherical equivalent (SE) > ± 5 diopter (D), applanation IOP ...

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    23. Corneal Stromal Demarcation Line Determined With Anterior Segment Optical Coherence Tomography Following a Very High Intensity Corneal Collagen Cross-Linking Protocol

      Corneal Stromal Demarcation Line Determined With Anterior Segment Optical Coherence Tomography Following a Very High Intensity Corneal Collagen Cross-Linking Protocol

      Purpose: To evaluate corneal stromal demarcation line depth after very high intensity (18 mW/cm2) ultraviolet-A irradiation for a 5-minute corneal collagen cross-linking (CXL) protocol with the use of anterior segment optical coherence tomography. Methods: This prospective interventional study enrolled 14 patients (18 eyes) with progressive keratoconus who underwent CXL with an ultraviolet-A irradiation intensity of 18 mW/cm2 for 5 minutes. One month postoperatively, corneal stromal demarcation line depth was measured with the use of anterior segment optical coherence tomography by 2 independent observers. The rate of reepithelialization and endothelial cell density at a 3-month follow-up period were also ...

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    24. Anomalous optical coherence tomography findings in Wyburn-Mason syndrome and isolated retinal arteriovenous malformation

      Anomalous optical coherence tomography findings in Wyburn-Mason syndrome and isolated retinal arteriovenous malformation

      We report 2 cases of unilateral retinal arteriovenous malformation (AVM) with previously unreported anomalies of the inner retinal layers detected on spectral domain optical coherence tomography (SD-OCT): a 5-year-old girl with a large unilateral retinal AVM, ipsilateral visual acuity of 20/200, and ipsilateral intracranial AVM; and a 10-year-old boy with a large unilateral retinal AVM, ipsilateral visual acuity of 20/20, ipsilateral temporal visual field defects, and no intracranial AVM. Both macular SD-OCT findings showed multiple large inner retinal vessels that created a prominent shadowing artifact, retinal thickening, and speckling and heterogeneity of inner retinal layers.

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