1. Articles in category: Ophthalmology

    553-576 of 6883 « 1 2 ... 21 22 23 24 25 26 27 ... 285 286 287 »
    1. Rates of Decline in Regions of the Visual Field Defined by Frequency-Domain Optical Coherence Tomography in Patients with -Mediated X-Linked Retinitis Pigmentosa

      Rates of Decline in Regions of the Visual Field Defined by Frequency-Domain Optical Coherence Tomography in Patients with -Mediated X-Linked Retinitis Pigmentosa

      Purpose To determine whether annual decline in visual field sensitivity is greater in the transition zone at the edge of the frequency-domain optical coherence tomography (fdOCT) inner segment ellipsoid zone (EZ) than at other locations in the visual field. Design Prospective, longitudinal, observational study. Participants Forty-four patients with X-linked retinitis pigmentosa (XLRP) resulting from a mutation in the RPGR gene. Methods Static perimetric fields (Humphrey 30-2; Carl Zeiss Meditec, Dublin, CA) were obtained annually for 4 years. Beginning with year 2, fdOCT scans were obtained annually with a Heidelberg Spectralis HRA + OCT (Heidelberg Engineering, Heidelberg, Germany). Main Outcome Measures The ...

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    2. Factors Affecting the Ability of the Spectral Domain Optical Coherence Tomograph to Detect Photographic Retinal Nerve Fiber Layer Defects

      Factors Affecting the Ability of the Spectral Domain Optical Coherence Tomograph to Detect Photographic Retinal Nerve Fiber Layer Defects

      Purpose To evaluate the ability of normative database classification (color-coded maps) of spectral domain optical coherence tomograph (SDOCT) in detecting wedge shaped retinal nerve fiber layer (RNFL) defects identified on photographs and the factors affecting the ability of SDOCT in detecting these RNFL defects. Methods In a cross-sectional study, 238 eyes (476 RNFL quadrants) of 172 normal subjects and 85 eyes (103 RNFL quadrants with wedge shaped RNFL defects) of 66 glaucoma patients underwent RNFL imaging with SDOCT. Logistic regression models were used to evaluate the factors associated with false positive and false negative RNFL classifications of the color-coded maps ...

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    3. The Evaluation of Prognostic Factors after Vitrectomy for Lamellar Macular Hole Using Optical Coherence Tomography

      The Evaluation of Prognostic Factors after Vitrectomy for Lamellar Macular Hole Using Optical Coherence Tomography

      Purpose To evaluate the prognostic factors that predict visual outcome after vitrectomy for lamellar macular hole using optical coherence tomography (OCT). Methods This study included 26 eyes that underwent pars plana vitrectomy, epiretinal membrane removal, and internal limiting membrane peeling for lamellar macular hole. The maximum parafoveal thickness, maximum height and diameter of lamellar macular hole, maximum height and diameter of intraretinal splitting, thinnest foveal floor thickness, and inner segment/outer segment disruption length on preoperative OCT image were investigated for prognostic factors that predict visual outcome. Results The mean follow-up period was 32.2 months and the mean best ...

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    4. Disease progression in iridocorneal angle tissues of BMP2-induced ocular hypertensive mice with optical coherence tomography

      Disease progression in iridocorneal angle tissues of BMP2-induced ocular hypertensive mice with optical coherence tomography

      Purpose: The goal of the present study was to test for the first time whether glaucomatous-like disease progression in a mouse can be assessed morphologically and functionally with spectral domain optical coherence tomography (SD-OCT). Methods: We monitored progressive changes in conventional outflow tissues of living mice overexpressing human bone morphogenetic protein 2 (BMP2), a model for glaucoma. Intraocular pressure (IOP) and outflow tissue morphology/Young's modulus were followed in mice for 36 days with rebound tonometry and SD-OCT, respectively. Results were compared to standard histological methods. Outflow facility was calculated from flow measurements with direct cannulation of anterior chambers ...

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    5. Evaluation of the adhesive properties of the cornea by means of optical coherence tomography in patients with meibomian gland dysfunction and lacrimal tear deficiency

      Evaluation of the adhesive properties of the cornea by means of optical coherence tomography in patients with meibomian gland dysfunction and lacrimal tear deficiency

      Objective The aim was to determine the influence of meibomian gland dysfunction (MGD) and aqueous tear deficiency dry eye (ADDE) on the adhesive properties of the central cornea by means of optical coherence tomography (OCT), and to investigate the relationship between corneal adhesiveness and classical tear tests, as well as the reliability of results, in these lacrimal functional unit disorders. Design Prospective, case-control study. Methods Twenty-eight patients with MGD and 27 patients with ADDE were studied. A group of 32 healthy subjects of similar age and gender distribution served as a control group. The adhesive properties of the anterior corneal ...

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    6. Optical Coherence Tomography Findings in Recurrent Corneal Erosion Syndrome

      Optical Coherence Tomography Findings in Recurrent Corneal Erosion Syndrome

      Purpose: To report the findings of optical coherence tomography (OCT) in the corneas of patients with recurrent corneal erosion syndrome (RCES). Methods: Ten normal subjects and 25 patients with RCES were recruited for the study. Ten patients with RCES suffered from an acute episode of pain and 15 patients complained of typical chronic symptoms of RCES. All eyes were scanned with the anterior segment 5 line raster acquisition protocol of the Cirrus HD-OCT platform (Zeiss). The etiology of RCES was investigated and treatment was provided following a standard clinical protocol. Scans were obtained at different stages of the pathology and ...

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    7. Dynamics of Macular Hole Closure in Gas-Filled Eyes within 24 h of Surgery Observed with Swept Source Optical Coherence Tomography

      Dynamics of Macular Hole Closure in Gas-Filled Eyes within 24 h of Surgery Observed with Swept Source Optical Coherence Tomography

      Background/Aims: To investigate the dynamics of macular hole (MH) closure in gas-filled eyes starting 20 min after vitrectomy using swept source optical coherence tomography (SS-OCT). Methods: Twenty consecutive eyes with MH underwent vitrectomy with internal limiting membrane peeling and gas tamponade. SS-OCT imaging was performed approximately 20 min after the operation, and then once a day, until MH closure was confirmed. The correlation between the base, top and minimum hole diameters and the duration required for MH closure was investigated. Results: MH closure in gas-filled eyes was confirmed in 1 eye on day 0, 10 eyes on day 1 ...

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    8. En Face Imaging of the Choroid in Polypoidal Choroidal Vasculopathy Using Swept-Source Optical Coherence Tomography

      En Face Imaging of the Choroid in Polypoidal Choroidal Vasculopathy Using Swept-Source Optical Coherence Tomography

      Objective To define morphological features of polypoidal choroidal vasculopathy (PCV) using en face images from swept source optical coherence tomography (SS-OCT). Design Prospective cross-sectional study. Methods Ten eyes from 6 patients with PCV and 10 eyes from 5 age-matched normal subjects. All subjects were prospectively scanned with a prototype SS-OCT system. A motion correction algorithm was applied to correct and merge scans into a single volumetric dataset. En face images were generated at intervals of 4.13 μm (1 pixel) relative to the Bruch's membrane. Results Age ± standard deviation for the PCV group was 62.4 (± 12.1) years ...

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    9. Analysis of multimode fiber bundles for endoscopic spectral-domain optical coherence tomography

      Analysis of multimode fiber bundles for endoscopic spectral-domain optical coherence tomography

      A theoretical analysis of the use of a fiber bundle in spectral-domain optical coherence tomography (OCT) systems is presented. The fiber bundle enables a flexible endoscopic design and provides fast, parallelized acquisition of the OCT data. However, the multimode characteristic of the fibers in the fiber bundle affects the depth sensitivity of the imaging system. A description of light interference in a multimode fiber is presented along with numerical simulations and experimental studies to illustrate the theoretical analysis.

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    10. The use of time-lapse optical coherence tomography to image the effects of microapplied toxins on the retina

      The use of time-lapse optical coherence tomography to image the effects of microapplied toxins on the retina

      Purpose: We developed a novel technique using a drug microperfusion device and time-lapse optical coherence tomography (OCT) for accelerated drug screening and retinotoxin characterization. Methods: Using an ex vivo rabbit eyecup preparation, we studied retinotoxin effects in real-time by microperfusing small retinal areas under a transparent fluoropolymer tube. Known retinotoxic agents were applied to the retina for 5 minute periods while changes in retinal structure, thickness, and reflectance were monitored with OCT. The OCT images of two agents with dissimilar mechanisms, cyanide and kainic acid, were compared with their structural changes seen histologically. Results: We found the actions of retinotoxic ...

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    11. Management of intrastromal glass foreign body based on anterior segment optical coherence tomography and Pentacam analysis

      Management of intrastromal glass foreign body based on anterior segment optical coherence tomography and Pentacam analysis

      We read with interest the article by Huda et al. [ 1 ] which reported the clinical aspects and the imaging of a patient with intrastromal glass foreign bodies after a road traffic accident using both anterior segment optical coherence tomography (AS-OCT) and ocular Pentacam, and “demonstrated that AS-OCT and ocular Pentacam are effective and necessary procedures for both the diagnosis and follow-up of intracorneal foreign bodies”. While this paper contributed to our understanding of how AS-OCT and ocular Pentacam may potentially affect the management protocol in these cases, there are relevant additions that we will like to highlight. We encountered a ...

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    12. Spectral Domain OCT Imaging Techniques in Tamoxifen Retinopathy

      Spectral Domain OCT Imaging Techniques in Tamoxifen Retinopathy

      Purpose: To highlight the use of high-density spectral domain optical coherence tomography (SD-OCT) in the detection of tamoxifen retinopathy. Case Report: An 82-year-old asymptomatic woman with a history of tamoxifen therapy for breast cancer was found to have bilateral refractile retinal deposits on fundus examination. Detection on SD-OCT was compared across imaging techniques. High-density SD-OCT demonstrated hyperreflective deposits in the inner retinal layers of each eye consistent with the diagnosis of tamoxifen retinopathy. Conclusions: The optimal SD-OCT scan technique depends on the ocular condition being imaged. High-density scan techniques require longer acquisition time but may enhance the detection of focal ...

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    13. ARVO Imaging in the Eye Conference Denver Colorado, May 2, 2015

      ARVO Imaging in the Eye Conference Denver Colorado, May 2, 2015

      Join your colleagues for the ARVO Imaging Conference (formerly ISIE), Saturday, May 2, 2015 in Denver. This one-day conference takes place the day before the ARVO Annual Meeting. See more information by clicking HERE . The ARVO Imaging Conference is highly recommended by your peers as a valuable source of in-depth information on the newest techniques and technologies in imaging. “This conference pulls together all the various imaging modalities with all tissues and diseases. It provides not only an invaluable insight into new and state-of-the-art technology across the board, but it also introduces the participants into a bit of every exciting ...

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    14. Motion Artefact Correction in Retinal Optical Coherence Tomography Using Local Symmetry

      Motion Artefact Correction in Retinal Optical Coherence Tomography Using Local Symmetry

      Patient movements during the acquisition of SD-OCT scans create substantial motion artefacts in the volumetric data that hinder registration and 3D analysis and can be mistaken for pathologies. In this paper we propose a method to correct these artefacts using a single volume scan while still retaining the overall shape of the retina. The method was quantitatively validated using a set of synthetic SD-OCT volumes and qualitatively by a group of trained OCT grading experts on 100 SD-OCT scans. Furthermore, we compared the motion compensation estimation by the proposed method with a hardware eye tracker on 100 SD-OCT volumes.

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    15. In vivo imaging of human vasculature in the chorioretinal complex using phase-variance contrast method with phase-stabilized 1-μm swept-source optical coherence tomography

      In vivo imaging of human vasculature in the chorioretinal complex using phase-variance contrast method with phase-stabilized 1-μm swept-source optical coherence tomography

      We present a noninvasive phase-variance (pv)–based motion contrast method for depth-resolved imaging of the human chorioretinal complex microcirculation with a newly developed phase-stabilized high speed (100-kHz A-scans/s) 1 - μ m swept-source optical coherence tomography (SSOCT) system. Compared to our previous spectral-domain (spectrometer based) pv-spectral domain OCT (SDOCT) system, this system has the advantages of higher sensitivity, reduced fringe wash-out for high blood flow speeds and deeper penetration in choroid. High phase stability SSOCT imaging was achieved by using a computationally efficient phase stabilization approach. This process does not require additional calibration hardware and complex numerical procedures. Our phase stabilization ...

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    16. Test-Retest Variability of Retinal Nerve Fiber Layer Thickness and Macular Ganglion Cell-Inner Plexiform Layer Thickness Measurements Using Spectral-Domain Optical Coherence Tomography

      Test-Retest Variability of Retinal Nerve Fiber Layer Thickness and Macular Ganglion Cell-Inner Plexiform Layer Thickness Measurements Using Spectral-Domain Optical Coherence Tomography

      Purpose: To evaluate the test-retest variability of spectral-domain optical coherence tomography (OCT) in measurement of retinal nerve fiber layer (RNFL) thickness and macular ganglion cell-inner plexiform layer (GCIPL) thickness. Methods: A total of 65 eyes of healthy subjects were enrolled in this observational cross-sectional study. RNFL thickness and GCIPL thickness were measured using the repeat scan optic cube and macular cube protocol using Cirrus HD-OCT (software version 6.0). A single operator obtained 3 measurements during 1 session to determine test-retest variability. Intrasession repeatability was defined by intraclass correlation, limits of agreement, and coefficient of variation. Results: The mean age ...

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    17. USC Eye Institute Adds 12 Faculty Physician Scientists in 2014

      USC Eye Institute Adds 12 Faculty Physician Scientists in 2014

      The University of Southern California (USC) Eye Institute has recruited 12 physician scientists from some of the world’s leading institutions, specializing in the diagnosis and treatment of a wide spectrum of vision disorders. The recruitment is part of an overarching growth strategy that anticipates increased demand in eye care services. According to the National Eye Institute, more than 65 percent of Americans 40 years or older suffer from some sort of vision impairment – ranging from near- or far-sightedness to blindness. That number is expected to swell as the population ages. Each physician recruit contributes expertise in a unique area ...

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    18. Comparative analysis of corneal measurements obtained from a Scheimpflug camera and an integrated Placido-optical coherence tomography device in normal and keratoconic eyes

      Comparative analysis of corneal measurements obtained from a Scheimpflug camera and an integrated Placido-optical coherence tomography device in normal and keratoconic eyes

      Purpose To assess the agreement between a Scheimpflug camera (Pentacam) and a combined Placido-optical coherence tomography device (Visante OMNI) in measuring corneal curvature, thickness and elevation values in normal and keratoconic eyes. Methods Corneal measurements of 110 normal eyes (one eye per subject) and 70 keratoconic eyes were obtained from both devices and compared. Agreement was determined using the Bland–Altman analysis 95% limits of agreement (LoA). Results The Pentacam measured significantly greater keratometry readings in the flattest (K1) and steepest meridians (K2) in normal and keratoconic eyes. The 95% LoA in normal eyes were −0.32 to 0.59 ...

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    19. The Effect of Systemic Tamsulosin Hydrochloride on Choroidal Thickness Measured by Enhanced Depth Imaging Spectral Domain Optical Coherence Tomography

      The Effect of Systemic Tamsulosin Hydrochloride on Choroidal Thickness Measured by Enhanced Depth Imaging Spectral Domain Optical Coherence Tomography

      Background : To evaluate the effects of selective α 1A -adrenoceptor antagonist tamsulosin hydrochloride on choroidal thickness using enhanced depth imaging spectral-domain optical coherence tomography (EDI-OCT). Methods : This is a prospective observational study including 29 eyes of 29 patients with newly diagnosed benign prostatic hyperplasia. Choroidal thickness and retrobulbar ocular blood flow measurements were performed at baseline and after 3 months of treatment. Results were analyzed by the masked observer. Results : The mean subfoveal choroidal thickness (275.8–291.9 µm) and thicknesses 750 µm nasal (257.9–270.4 µm) and 750 µm temporal (262.4–277.0 µm) to the ...

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    20. Comparison of event-based analysis of glaucoma progression assessed subjectively on visual fields and retinal nerve fibre layer attenuation measured by optical coherence tomography

      Comparison of event-based analysis of glaucoma progression assessed subjectively on visual fields and retinal nerve fibre layer attenuation measured by optical coherence tomography

      The purpose is to study the ability of an event-based analysis of retinal nerve fibre layer (RNFL) attenuation measured by Stratus ® optical coherence tomography (OCT) and to detect progression across the spectrum of glaucoma. Adult glaucoma suspects, ocular hypertensives and glaucoma patients who had undergone baseline RNFL thickness measurement on Stratus OCT and reliable automated visual field examination by Humphrey’s visual field analyser prior to March 2007 and had 5-year follow-up data were recruited. Progression on OCT was defined by two criteria: decrease in average RNFL thickness from baseline by at least 10 and 20 µ. Visual field progression was ...

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    21. Optical coherence tomography for retinal imaging in multiple sclerosis

      Optical coherence tomography for retinal imaging in multiple sclerosis

      Visual disturbances caused by inflammatory and demyelinating processes of the visual system, mainly in the optic nerve, are a common symptom in multiple sclerosis (MS). Optical coherence tomography (OCT) is a tool that is increasingly used for quantifying retinal damage in MS and other neurologic diseases. Based on spectral interferometry, it uses low-coherent infrared light to generate high-resolution spatial images of the retina. The retinal nerve fiber layer (RNFL) consists of unmyelinated axons that form the optic nerve, and thus represents a part of the central nervous system. OCT allows for noninvasive measurements of RNFL thickness in micrometer resolution. With ...

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