1. Articles in category: Ophthalmology

    577-600 of 6008 « 1 2 ... 22 23 24 25 26 27 28 ... 249 250 251 »
    1. Optical coherence tomography combined with videokeratography to differentiate mild keratoconus subtypes

      Optical coherence tomography combined with videokeratography to differentiate mild keratoconus subtypes

      PURPOSE: To develop parameters using a combination of optical coherence tomography (OCT) and videokeratography to detect early keratoconus. METHODS: Videokeratography, wavefront analysis, and measured OCT indices were performed on 180 normal eyes, 46 eyes with moderate keratoconus, 54 eyes with early keratoconus, 7 eyes with forme fruste keratoconus, and 16 eyes with keratoconus "suspect" to determine the most sensitive parameters for separating these groups. RESULTS: A combination of videokeratography and OCT indices (inferior-superior [I-S] value and minimum pachymetry) was statistically the most significant in separating the keratoconus groups from normal eyes (P < .001). Using a newly derived index, the minimum ...

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    2. Heidelberg Spectralis OCT Eye Examinations in Space

      Heidelberg Spectralis OCT Eye Examinations in Space

      Since its arrival at the International Space Station (ISS) on June 15 th , 2013, Heidelberg Engineering’s Spectralis OCT device is being used regularly for eye examinations of ISS crewmembers. First on-orbit tests of the instrument were conducted successfully on June 21 of last year. The first ever OCT examination in space was performed with a commercial SPECTRALIS OCT device on board ISS on October 16, 2013. Since then, ISS crewmembers are being examined in 1- to 2-week intervals. The examinations are part of NASA’s Ocular Health Study, which seeks to understand ocular changes in astronauts during long-term space ...

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    3. Optical Coherence Tomography in Parkinson's Disease: Is the Retina a Biomarker?

      Optical Coherence Tomography in Parkinson's Disease: Is the Retina a Biomarker?

      Visual symptoms are a common feature in patients with Parkinson's disease (PD), and retinal dopamine loss and dysfunctions in foveal vision have been described in PD patients. Because visual hallucination (VH) is a specific feature of PD which is differentiated from other parkinsonian disorders, defective visual information processing from both the central and peripheral pathways is suggested to be the pathophysiological mechanisms of VH in PD. Decreased visual acuity as well as impaired contrast sensitivity and color vision is known to be related to the appearance of VH in PD. However, these functional studies were also affected by cognitive ...

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    4. Optical coherence tomography: a quantitative tool to screen for papilledema in craniosynostosis

      Optical coherence tomography: a quantitative tool to screen for papilledema in craniosynostosis

      Purpose Our aim was to evaluate if optical coherence tomography (OCT) can be used as an alternative for fundoscopy to screen for increased intracranial pressure (ICP) in children with craniosynostosis Methods We performed a prospective cohort study at the Dutch Craniofacial Centre. We included 38 patients with nonsyndromic scaphocephaly and Crouzon’s syndrome aged 3–8 years old, in whom we scored complaints suggestive of increased ICP and performed fundoscopy and OCT. Main outcome measures total retinal thickness (TRT) which was measured on 58 OCT scans. Results Forty-three percent of fundoscopies revealed pathologic changes of the papil in at least ...

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    5. Reproducibility of disc and macula optical coherence tomography using the Canon OCT-HS100 as compared with the Zeiss Cirrus HD-OCT

      Reproducibility of disc and macula optical coherence tomography using the Canon OCT-HS100 as compared with the Zeiss Cirrus HD-OCT

      Purpose: In a clinical setting, the usefulness of optical coherence tomography (OCT) is strongly dependent on reproducibility of the measurement. The aim of the present study was to evaluate macula and optic disc measurement reproducibility with the new spectral-domain OCT (SD-OCT) from Canon (Canon OCT-HS100) and to compare reproducibility and obtained measurements with the Zeiss Cirrus HD-OCT. Methods: Macula and optic disc parameters from the right eyes of 31 subjects were obtained twice with both instruments. Interoperator reproducibility was evaluated by use of the coefficient of repeatability (CR), and the obtained measurements were compared between the instruments. Results: No difference ...

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    6. Optical coherence tomography in the diagnosis and management of uveitis

      Optical coherence tomography in the diagnosis and management of uveitis

      Optical coherence tomography (OCT) has become an integral tool in the imaging of numerous diseases of the posterior segment. The diagnostic investigation of infectious and noninfectious uveitic conditions often requires multiple imaging modalities in the appropriate clinical context. Modern OCT technology has proved useful not only in the diagnostic investigation of these conditions, but also in monitoring of their clinical course and therapeutic response. Inflammation-induced changes at the level of the retina, retinal pigment epithelium, and choroid can now easily be identified in these conditions using OCT. Prognostic information on visual acuity outcome can also be estimated based on OCT ...

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    7. Microstructure of subretinal drusenoid deposits revealed by adaptive optics imaging

      Microstructure of subretinal drusenoid deposits revealed by adaptive optics imaging

      Subretinal drusenoid deposits (SDD), a recently recognized lesion associated with progression of age-related macular degeneration, were imaged with adaptive optics scanning laser ophthalmoscopy (AO-SLO) and optical coherence tomography (AO-OCT). AO-SLO revealed a distinct en face structure of stage 3 SDD, showing a hyporeflective annulus surrounded reflective core packed with hyperreflective dots bearing a superficial similarity to the photoreceptors in the unaffected retina. However, AO-OCT suggested that the speckled appearance over the SDD rendered by AO-SLO was the lesion material itself, rather than photoreceptors. AO-OCT assists proper interpretation and understanding of the SDD structure and the lesions’ impact on surrounding photoreceptors ...

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    8. Relationship between Severity of Obstructive Sleep Apnea Syndrome and Retinal Nerve Fiber Layer Thickness

      Relationship between Severity of Obstructive Sleep Apnea Syndrome and Retinal Nerve Fiber Layer Thickness

      Purpose To determine if there is a significant correlation between the peripapillary retinal nerve fiber layer (RNFL) thickness, foveal thickness, total macular volume, and the severity of obstructive sleep apnea syndrome. DESIGN: Prospective study. Methods One hundred twenty-eight consecutive subjects who underwent polysomnography were studied. Optical coherence tomography (OCT) was used to measure the peripapillary RNFL, foveal thickness, and total macular volume. The Pearson correlation coefficient was used to determine the relationship between the apnea-hypopnea index and OCT and other parameters. Multiple regression analysis was used to determine the independent factors for the RNFL sectors that were the most strongly ...

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    9. Vitreous Changes in High Myopia Observed by Swept-Source Optical Coherence Tomography

      Vitreous Changes in High Myopia Observed by Swept-Source Optical Coherence Tomography

      PURPOSE. To observe vitreous changes in high myopia using swept-source optical coherence tomography (SS-OCT). METHODS. We performed slit-lamp biomicroscopy and SS-OCT in the highly myopic right eyes of 151 patients (mean age, 52.7 years; mean refraction, -11.4 diopters [D]) and the right eyes with no myopia of 363 healthy control volunteers (mean age, 52.8 years; mean refraction, -1.4 D). To estimate the sizes of the posterior precortical vitreous pockets (PPVPs), we measured the height between the fovea and the anterior border of the PPVPs. RESULTS. Patients with partial posterior vitreous detachments (PVDs) around the macula and ...

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      Mentions: Gunma University
    10. Normal macular structure measured with optical coherence tomography across ethnicity

      Normal macular structure measured with optical coherence tomography across ethnicity

      Objective The difference in prevalence of various retinal pathologies in people of different ethnicity is well established. Optical coherence tomography (OCT) is a widely used technique that allows quantitative analysis of macular structure. In this study, we investigated macular layer morphology in healthy subjects using high-resolution spectral domain (SD) OCT across ethnicities comparing Asian (ie, Indian subcontinent) and Caucasian individuals. Methods 133 healthy volunteers (67—Asian, 66—Caucasian) were examined using SD-OCT. Average retinal and nerve fibre layer thickness were measured in a semiautomated way. Analysis of the measurements of each retinal layer at the macula was quantified using tomograms ...

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    11. Using continuous intraoperative optical coherence tomography measurements of the aphakic eye for intraocular lens power calculation

      Using continuous intraoperative optical coherence tomography measurements of the aphakic eye for intraocular lens power calculation

      Background/aims To include intraoperative measurements of the anterior lens capsule of the aphakic eye into the intraocular lens power calculation (IPC) process and to compare the refractive outcome with conventional IPC formulae. Methods In this prospective study, a prototype operating microscope with an integrated continuous optical coherence tomography (OCT) device (Visante attached to OPMI VISU 200, Carl Zeiss Meditec AG, Germany) was used to measure the anterior lens capsule position after implanting a capsular tension ring (CTR). Optical biometry (intraocular lens (IOL) Master 500) and ACMaster measurements (Carl Zeiss Meditec AG, Germany) were performed before surgery. Autorefraction and subjective ...

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    12. Comparison of slit lamp-adapted optical coherence tomography features of fellow eyes of acute primary angle closure and eyes with open angle glaucoma

      Comparison of slit lamp-adapted optical coherence tomography features of fellow eyes of acute primary angle closure and eyes with open angle glaucoma

      Purpose The aim of this study was to assess the possibility of discriminating a narrow and occludable chamber angle by means of digital gonioscopy. Methods In a prospective controlled clinical study 40 eyes of 40 patients were enrolled. 20 patients that had suffered acute angle closure glaucoma (ACG) on the fellow eye were compared to 20 patients with open angle glaucoma (OAG). Anterior segment imaging with SL-OCT (Heidelberg Engineering, Heidelberg, Germany) enabled the delineation, by means of automatic signal analysis, of several important parameters of the anterior chamber angle region, which were compared to those revealed from direct contact glass ...

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    13. Real-time acquisition and display of flow contrast using speckle variance optical coherence tomography in a graphics processing unit

      Real-time acquisition and display of flow contrast using speckle variance optical coherence tomography in a graphics processing unit

      In this report, we describe a graphics processing unit (GPU)-accelerated processing platform for real-time acquisition and display of flow contrast images with Fourier domain optical coherence tomography (FDOCT) in mouse and human eyes in vivo . Motion contrast from blood flow is processed using the speckle variance OCT (svOCT) technique, which relies on the acquisition of multiple B-scan frames at the same location and tracking the change of the speckle pattern. Real-time mouse and human retinal imaging using two different custom-built OCT systems with processing and display performed on GPU are presented with an in-depth analysis of performance metrics. The ...

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    14. Repeatability and Reproducibility of Eight Macular Intra-Retinal Layer Thicknesses Determined by an Automated Segmentation Algorithm Using Two SD-OCT Instrument

      Repeatability and Reproducibility of Eight Macular Intra-Retinal Layer Thicknesses Determined by an Automated Segmentation Algorithm Using Two SD-OCT Instrument

      Purpose To evaluate the repeatability, reproducibility, and agreement of thickness profile measurements of eight intra-retinal layers determined by an automated algorithm applied to optical coherence tomography (OCT) images from two different instruments. Methods Twenty normal subjects (12 males, 8 females; 24 to 32 years old) were enrolled. Imaging was performed with a custom built ultra-high resolution OCT instrument (UHR-OCT, ~3 µm resolution) and a commercial RTVue100 OCT (~5 µm resolution) instrument. An automated algorithm was developed to segment the macular retina into eight layers and quantitate the thickness of each layer. The right eye of each subject was imaged two ...

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    15. Use of optical coherence tomography to evaluate visual acuity and visual field changes in dengue Fever

      Use of optical coherence tomography to evaluate visual acuity and visual field changes in dengue Fever

      Dengue fever is a viral disease that is transmitted by mosquitoes and affects humans. In rare cases, dengue fever can cause visual impairment, which usually occurs within 1 month after contracting dengue fever and ranges from mild blurring of vision to severe blindness. Visual impairment due to dengue fever can be detected through angiography, retinography, optical coherence tomography (OCT) imaging, electroretinography, event electroencephalography (visually evoked potentials), and visual field analysis. The purpose of this study is to report changes in the eye captured using fluorescein angiography, indocyanine green, and OCT in 3 cases of dengue fever visual impairment associated with ...

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    16. High-Resolution Optical Coherence Tomography-Guided Donor Tissue Preparation for Descemet Membrane Endothelial Keratoplasty Using the Reverse Big Bubble Technique

      High-Resolution Optical Coherence Tomography-Guided Donor Tissue Preparation for Descemet Membrane Endothelial Keratoplasty Using the Reverse Big Bubble Technique

      Purpose: The aim of this study was to assess the feasibility of high-resolution spectral domain optical coherence tomography (HR-SDOCT) to guide donor tissue preparation in Descemet membrane endothelial keratoplasty using the reverse big bubble technique. Methods: Three corneoscleral discs were included in this ex vivo experimental study. A 27-G cannula was introduced into each cornea at the periphery by 3 different surgeons. Each surgeon attempted to achieve the ideal depth (pre-Descemetic plane) of the tip of the cannula for air injection to produce the reverse big bubble to separate the Descemet membrane (DM) from the posterior stroma. A supine optical ...

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    17. Anterior-Segment Optical Coherence Tomography Investigation of Corneal Deturgescence and Epithelial Remodeling After DSAEK

      Anterior-Segment Optical Coherence Tomography Investigation of Corneal Deturgescence and Epithelial Remodeling After DSAEK

      Purpose: The aim of this study was to evaluate via Fourier-domain anterior-segment optical coherence tomography 3-dimensional corneal, epithelial, and graft thickness changes after Descemet stripping automated endothelial keratoplasty (DSAEK). Methods: Sixteen eyes were investigated preoperatively and up to 6 months postoperatively for preoperative and postoperative central corneal thickness (CCT), minimum corneal thickness, central graft thickness (CGT), and for epithelial topographic thickness variability. An age-matched and gender-matched control group of 32 healthy eyes was used for comparison. Results: In the DSAEK group, the preoperative CCT was 582.32 +/- 45.24 (550-615) [mu]m. One-month postoperatively, the CCT was 736.26 +/- 34 ...

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    18. Spectral-Domain Optical Coherence Tomography Staging and Autofluorescence Imaging in Achromatopsia

      Spectral-Domain Optical Coherence Tomography Staging and Autofluorescence Imaging in Achromatopsia

      Importance Evidence is mounting that achromatopsia is a progressive retinal degeneration, and treatments for this condition are on the horizon. Objectives To categorize achromatopsia into clinically identifiable stages using spectral-domain optical coherence tomography and to describe fundus autofluorescence imaging in this condition. Design, Setting, and Participants A prospective observational study was performed between 2010 and 2012 at the Edward S. Harkness Eye Institute, New York-Presbyterian Hospital. Participants included 17 patients (aged 10-62 years) with full-field electroretinography-confirmed achromatopsia. Main Outcomes and Measures Spectral-domain optical coherence tomography features and staging system, fundus autofluorescence and near-infrared reflectance features and their correlation to optical ...

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    19. Evaluation of cystoid change phenotypes in ocular toxoplasmosis using optical coherence tomography

      Evaluation of cystoid change phenotypes in ocular toxoplasmosis using optical coherence tomography

      Purpose To present unique cystoid changes occurring in patients with ocular toxoplasmosis observed in spectral domain optical coherence tomography (OCT). Methods Forty-six patients (80 eyes) with a diagnosis of ocular toxoplasmosis, who underwent volume OCT examination between January 2005 and October 2012, were retrospectively collected. Review of clinical examination findings, fundus photographs, fluorescein angiograms (FA) and OCT image sets obtained at initial visits and follow-up. Qualitative and quantitative analyses of cystoid space phenotypes visualized using OCT. Results Of the 80 eyes included, 17 eyes (15 patients) demonstrated cystoid changes in the macula on OCT. Six eyes (7.5%) had cystoid ...

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    20. A Morphological Study of Retinal Changes in Unilateral Amblyopia Using Optical Coherence Tomography Image Segmentation

      A Morphological Study of Retinal Changes in Unilateral Amblyopia Using Optical Coherence Tomography Image Segmentation

      Objective The purpose of this study was to evaluate the possible structural changes of the macula in patients with unilateral amblyopia using optical coherence tomography (OCT) image segmentation. Patients and Methods 38 consecutive patients (16 male; mean age 32.4±17.6 years; range 6–67 years) with unilateral amblyopia were involved in this study. OCT examinations were performed with a time-domain OCT device, and a custom-built OCT image analysis software (OCTRIMA) was used for OCT image segmentation. The axial length (AL) was measured by a LenStar LS 900 device. Macular layer thickness, AL and manifest spherical equivalent refraction (MRSE ...

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    21. Agreement of Corneal Epithelial Profiles Produced by Automated Segmentation of SD-OCT Images Having Different Optical Resolutions

      Agreement of Corneal Epithelial Profiles Produced by Automated Segmentation of SD-OCT Images Having Different Optical Resolutions

      Objective: Using a custom-developed segmentation algorithm, agreement of corneal epithelial thickness profile measurements between two spectral domain optical coherence tomography (SD-OCT) systems was assessed. Methods: Eighteen left eyes (18 subjects; mean+/-standard deviation; age, 23.2+/-0.9 years) were imaged twice on nonconsecutive days by a custom-built ultra-high resolution OCT (UHR-OCT) system and a commercial RTVue OCT system. A segmentation algorithm based on axial gradient information and a shortest path search was developed to measure corneal epithelial thickness profiles from the SD-OCT images. Results: There was good correlation between the automated and manual segmentation positions of the epithelium. The ...

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    22. The Premacular Bursa's Shape Revealed In Vivo by Swept-Source Optical Coherence Tomography

      The Premacular Bursa's Shape Revealed In Vivo by Swept-Source Optical Coherence Tomography

      Objective To resolve the controversy surrounding the shape and relationship of posterior vitreous spaces by characterizing the connections between the premacular bursa, the area of Martegiani, and Cloquet's canal. Design Comprehensive posterior vitreous maps were created using swept-source optical coherence tomography (SS OCT) in a cross-sectional study. Participants The posterior vitreous of 102 eyes of 51 volunteers 21 to 54 years of age without ocular pathologic features was imaged using SS OCT. Methods The DRI OCT-1 Atlantis 3D SS OCT (Topcon Medical Systems, Oakland, NJ) was used to acquire scans of the posterior vitreous over an 18×18-mm area ...

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    23. Effect of optical coherence tomography scan pattern and density on the detection of full-thickness macular holes

      Effect of optical coherence tomography scan pattern and density on the detection of full-thickness macular holes

      Purpose To evaluate the impact of different scan patterns and scan densities on small full-thickness macular hole (MH) detection. Design Retrospective cross-sectional analysis. Methods Analysis was performed on 25 eyes from 24 patients with full-thickness MHs imaged with the Heidelberg Spectralis HRA+OCT. Included eyes underwent concurrent imaging with a standard (61-line) raster volume and a 24-line radial pattern. A 6-line radial scan pattern was extrapolated from the higher density radial pattern. Comparisons of the missed hole rate as well as the proportion of individual B-scans demonstrating a full-thickness defect (termed “full-thickness detection index”) were carried out for the three ...

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