1. Articles in category: Ophthalmology

    1-24 of 6166 1 2 3 4 ... 255 256 257 »
    1. Macular Thickness Measurements using Copernicus Spectral Domain Optical Coherence Tomography

      Macular Thickness Measurements using Copernicus Spectral Domain Optical Coherence Tomography

      Purpose To provide normal macular thickness measurements using Spectral Domain Optical Coherence Tomography (SDOCT, Copernicus, Optopol Technologies, Zawierci, Poland). Methods Fifty eight eyes of 58 healthy subjects were included in this prospective study. All subjects had comprehensive ophthalmic examination including best-corrected visual acuity (BCVA). All the subjects underwent Copernicus SDOCT. Central foveal thickness (CFT) and photoreceptor layer (PRL) thickness were measured and expressed as mean and standard deviation. Mean retinal thickness for each of the 9 regions defined in the Early Treatment Diabetic Retinopathy Study were reported. The data was compared with published literature in Indians using Stratus and Spectralis ...

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    2. Findings of secondary corneal amyloidosis with ultrahigh-resolution optical coherence tomography

      Findings of secondary corneal amyloidosis  with ultrahigh-resolution optical coherence  tomography

      Purpose: To describe observations by ultrahigh-resolution optical coherence tomography (OCT) in a secondary corneal amyloidosis (SCA) patient with histological analysis of excised tissue. A unique finding under OCT of her fellow eye is also described. Case: A 39-year-old female had suffered from trichiasis in both of her eyes for more than 30 years. Slit-lamp examination showed a milky-white soft mass on her left cornea and a linear opacity on the fellow cornea at the cilia-attached region. OCT demonstrated the presence of a mass region within a thin epithelial layer and no destruction of Bowman’s layer in her left cornea ...

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    3. Detection and Differentiation of Intraretinal Hemorrhage in Spectral Domain Optical Coherence Tomography

      Detection and Differentiation of Intraretinal Hemorrhage in Spectral Domain Optical Coherence Tomography

      Purpose : The purpose of this study was to classify and detect intraretinal hemorrhage (IRH) in spectral domain optical coherence tomography (SD-OCT). Methods : Initially the presentation of IRH in BRVO-patients in SD-OCT was described by one reader comparing color-fundus (CF) and SD-OCT using dedicated software. Based on these established characteristics, the presence and the severity of IRH in SD-OCT and CF were assessed by two other masked readers and the inter-device and the inter-observer agreement were evaluated. Further the area of IRH was compared. Results : About 895 single B-scans of 24 eyes were analyzed. About 61% of SD-OCT scans and 46 ...

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    4. Interocular symmetry of retinal nerve fibre layer thickness in healthy eyes: a spectral-domain optical coherence tomographic study

      Interocular symmetry of retinal nerve fibre layer thickness in healthy eyes: a spectral-domain optical coherence tomographic study

      Purpose This study was performed to investigate the interocular symmetry of peripapillary retinal nerve fibre layer (RNFL) thickness, as measured by Cirrus high-definition spectral-domain optical coherence tomography (OCT), in healthy eyes. A wide range of subject ages and refractive errors was examined. Methods The retinal nerve fibre layer thickness was measured in 1,234 healthy eyes from 617 subjects using OCT. Interocular differences (right eye minus left eye) in global area and quadrant nerve fibre layer thicknesses were measured. The effect of age and refractive error on interocular nerve fibre layer thickness difference was also examined. Results Means (and standard ...

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    5. Rapid, Accurate, and Non-Invasive Measurement of Zebrafish Axial Length and Other Eye Dimensions Using SD-OCT Allows Longitudinal Analysis of Myopia and Emmetropization

      Rapid, Accurate, and Non-Invasive Measurement of Zebrafish Axial Length and Other Eye Dimensions Using SD-OCT Allows Longitudinal Analysis of Myopia and Emmetropization

      Refractive errors in vision can be caused by aberrant axial length of the eye, irregular corneal shape, or lens abnormalities. Causes of eye length overgrowth include multiple genetic loci, and visual parameters. We evaluate zebrafish as a potential animal model for studies of the genetic, cellular, and signaling basis of emmetropization and myopia. Axial length and other eye dimensions of zebrafish were measured using spectral domain-optical coherence tomography (SD-OCT). We used ocular lens and body metrics to normalize and compare eye size and relative refractive error (difference between observed retinal radial length and controls) in wild-type and lrp2 zebrafish. Zebrafish ...

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    6. Assessment of choroidal thickness before and after steep Trendelenburg position using swept-source optical coherence tomography

      Assessment of choroidal thickness before and after steep Trendelenburg position using swept-source optical coherence tomography

      Background To evaluate changes in choroidal thickness before and after steep Trendelenburg position (STP, 40° head-down) using automated segmentation software to analyse swept-source optical coherence tomography (SS-OCT) data. Methods The eyes of 20 healthy volunteers underwent a three-dimensional wide scanning protocol with SS-OCT (Topcon, Tokyo, Japan) at baseline, immediately after STP was initiated, and 5, 10 and 15 min after STP; blood pressure and heart rate were measured concurrently. The predictive mean difference was calculated using a generalised linear mixed model that adjusted for potential confounders. Results Mean choroidal thickness significantly and transiently increased immediately (268.18±9.24 μm ...

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    7. Assessment of laser induction of Bruch's membrane disruption in monkey by spectral-domain optical coherence tomography

      Assessment of laser induction of Bruch's membrane disruption in monkey by spectral-domain optical coherence tomography

      Purpose Laser-induced choroidal neovascularisation is a widely used model for age-related macular degeneration. The success rates of induction have been relatively low in large animals such as monkeys. Our study aimed to investigate the laser-induced damages to the Bruch's membrane of monkeys using the spectral-domain optical coherence tomography (OCT). Methods Laser photocoagulation was performed in the posterior and peripheral fundus of a rhesus monkey using a 532 nm laser. The lesions were examined by fundus photography and spectral-domain OCT immediately after the procedure. Fluorescein angiography was performed after 3 and 4 weeks in the animal to assess the development ...

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    8. Swept-Source Optical Coherence Tomography Features of Choroidal Nevi

      Swept-Source Optical Coherence Tomography Features of Choroidal Nevi

      Purpose To investigate the morphological characteristics of choroidal nevi using swept-source optical coherence tomography and compare this with enhanced-depth optical coherence tomography. Design Retrospective observational case series Methods One choroidal nevus each from 30 eyes of 30 patients was included and received imaging with swept-source OCT (SS-OCT) and enhanced-depth imaging OCT (EDI-OCT). For SS-OCT, a scan acquisition protocol was utilized involving 12mm horizontal and vertical scans in the posterior fundus. The main outcome measures were morphological features of choroidal nevi obtained with SS-OCT imaging. These features were compared to images obtained with EDI-OCT. A two-tailed Fisher’s exact test was ...

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    9. Optical Coherence Tomography Assessment of Angle Anatomy Changes After Trabeculectomy in Primary Angle-Closure Glaucoma

      Optical Coherence Tomography Assessment of Angle Anatomy Changes After Trabeculectomy in Primary Angle-Closure Glaucoma

      Purpose: Using anterior chamber optical coherence tomography to evaluate changes in angle anatomy in patients with primary angle-closure glaucoma (PACG) before and after trabeculectomy. Methods: This is a prospective observational study in 38 eyes of 38 patients with PACG, who underwent trabeculectomy. We used customized software to analyze optical coherence tomography images (Visante) of all participants before and after the surgical treatment. Multivariate linear regression analysis was performed for predictors of percentage change in mean angle parameters, including scleral spur angle, angle opening distance, angle recess area, and trabecular-iris surface area. The main outcome measures were changes in angle parameters ...

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    10. OCT-Derived Comparison of Corneal Thickness Distribution and Asymmetry Differences Between Normal and Keratoconic Eyes

      OCT-Derived Comparison of Corneal Thickness Distribution and Asymmetry Differences Between Normal and Keratoconic Eyes

      Purpose: The aim of this study was to investigate the corneal thickness asymmetry indices in a large pool of patients with keratoconus derived using anterior segment optical coherence tomography (AS-OCT) in comparison with established Scheimpflug imaging-derived keratoconus classification indices. Methods: Six specific indices were comparatively investigated in this study encompassing 2 groups: keratoconic group A (175 eyes) and age- and gender-matched control group B (175 eyes). AS-OCT was used for corneal focal thinning and irregularity indices, namely the superior nasal minus inferior temporal (SN-IT), superior minus inferior (S-I), minimum minus median (Min-Med) focal thinning, and thickness range, defined as the ...

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    11. Noise-compensated Homotopic Non-local Regularized Reconstruction for Rapid Retinal Optical Coherence Tomography Image Acquisitions

      Noise-compensated Homotopic Non-local Regularized Reconstruction for Rapid Retinal Optical Coherence Tomography Image Acquisitions

      Background Optical coherence tomography (OCT) is a minimally invasive imaging technique, which utilizes the spatial and temporal coherence properties of optical waves backscattered from biological material. Recent advances in tunable lasers and infrared camera technologies have enabled an increase in the OCT imaging speed by a factor of more than 100, which is important for retinal imaging where we wish to study fast physiological processes in the biological tissue. However, the high scanning rate causes proportional decrease of the detector exposure time, resulting in a reduction of the system signal-to-noise ratio (SNR). One approach to improving the image quality of ...

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    12. CHOROIDAL THICKNESS MEASURED WITH SWEPT SOURCE OPTICAL COHERENCE TOMOGRAPHY BEFORE AND AFTER VITRECTOMY WITH INTERNAL LIMITING MEMBRANE PEELING FOR IDIOPATHIC EPIRETINAL MEMBRANES

      CHOROIDAL THICKNESS MEASURED WITH SWEPT SOURCE OPTICAL COHERENCE TOMOGRAPHY BEFORE AND AFTER VITRECTOMY WITH INTERNAL LIMITING MEMBRANE PEELING FOR IDIOPATHIC EPIRETINAL MEMBRANES

      Purpose: In eyes with epiretinal membranes (ERMs), retinal arteries become dilated and tortuous. This may correlate with the hemodynamics of the affected areas and possibly with choroidal thickness. The aim of this study was to estimate choroidal thickness before and after vitrectomy for idiopathic ERM in the operated eye and in the unaffected fellow eye. Methods: A prospective study of 21 patients with idiopathic ERMs. We obtained swept source optical coherence tomography images that simultaneously evaluated the vitreous, retina, and choroid. We performed choroidal thickness measurements before pars plana vitrectomy with ERM removal and internal limiting membrane peeling. We took ...

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    13. A comprehensive model for correcting RNFL readings of varying signal strengths in CIRRUS Optical Coherence Tomography (OCT)

      A comprehensive model for correcting RNFL readings of varying signal strengths in CIRRUS Optical Coherence Tomography (OCT)

      Purpose. Develop a model for the CIRRUSTM HD-OCT that allows for the comparison of retinal nerve fiber layer (RNFL) thickness measurements with dissimilar signal strengths (SS) and accounts for test-re-test variability. Methods. RNFLs were obtained in normals using the CIRRUSTM optic disc cube 200x200 protocol during a single encounter. Five RNFL scans were obtained with a SS of 9-10. Diffusion lens filters were used to degrade SS to obtain five scans at each SS group of 7-8, 5-6, and 3-4. The relationship between average RNFL thickness and SS was established and an equation was developed to allow for adjustment of ...

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    14. Evaluating Dissociated Optic Nerve Fiber Layer Appearance Using En Face Layer Imaging Produced by Optical Coherence Tomography

      Evaluating Dissociated Optic Nerve Fiber Layer Appearance Using En Face Layer Imaging Produced by Optical Coherence Tomography

      Purpose: To investigate the incidence of and risk factors for a dissociated optic nerve fiber layer (DONFL) appearance after pars plana vitrectomy (PPV). Methods: We retrospectively reviewed 189 eyes that underwent PPV with internal limiting membrane removal and judged the presence/absence of an apparent DONFL based on en face layer images produced by spectral-domain optical coherence tomography (SD-OCT). Results: An apparent DONFL was observed in 47 (24.9%) eyes. The incidence of an apparent DONFL was significantly higher in the macular hole (MH) group (76.5%) than in the non-MH group (epiretinal membrane, diabetic macular edema, retinal vein occlusion ...

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    15. The cellular origins of the outer retinal bands in optical coherence tomography images

      The cellular origins of the outer retinal bands in optical coherence tomography images

      Purpose: To test the recently proposed hypothesis that the second OCT outer retinal band originates from the inner segment ellipsoid, by measuring: 1) thickness of this band within single cones, and 2) its respective distance from the external limiting membrane and outer segment tips. Methods: Adaptive optics OCT images were obtained from four normal subjects. Images were obtained at foveal (2∘) and perifoveal (5∘) locations. Cones (n = 9593) were identified and segmented in three dimensions using custom software. Features corresponding to bands 1, 2, and 3 were automatically identified. Thickness of band 2 was assessed in each cell by fitting ...

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    16. Abbott Expands Cataract Surgery Product Portfolio through U.S. Distribution Agreement with Carl Zeiss Meditec

      Abbott Expands Cataract Surgery Product Portfolio through U.S. Distribution Agreement with Carl Zeiss Meditec

      Abbott and Carl Zeiss Meditec announced today that they have entered into a nonexclusive commercial collaboration in the United States. Under this agreement, Abbott will offer each company’s suite of cataract surgery products when developing clinical and contracting solutions with customers in the United States. This comprehensive offering, including synergistic diagnostics, visualization systems, lens extraction systems, and intraocular lenses, provides surgeons with access to a complete cataract surgery portfolio to assist them in maximizing visual outcomes and streamlining patient flow. "Together with surgeons, Abbott is committed to delivering unsurpassed visual outcomes to patients," said Murthy Simhambhatla, Ph.D., senior ...

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    17. 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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    18. 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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    19. 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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    20. 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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    21. 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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    22. 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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    23. 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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    24. 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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