1. Articles in category: Ophthalmology

    1-24 of 6318 1 2 3 4 ... 262 263 264 »
    1. 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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    2. 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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    3. 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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    4. 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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    5. 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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    6. 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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    7. 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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    8. 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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    9. 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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    10. 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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    11. 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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    12. 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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    13. Predicting Visual Outcomes for Macula-Off Rhegmatogenous Retinal Detachment with Optical Coherence Tomography

      Predicting Visual Outcomes for Macula-Off Rhegmatogenous Retinal Detachment with Optical Coherence Tomography

      Purpose. We evaluated the ability of novel optical coherence tomography (OCT) parameters to predict postoperative best-corrected visual acuity (BCVA) in macula-off rhegmatogenous retinal detachment (RRD) eyes. Methods. We reviewed the medical records of 56 consecutive eyes with macula-off RRD. Clinical findings were analyzed including the relationship between preoperative OCT findings and 6-month postoperative BCVA. Results. Six-month postoperative BCVA was significantly correlated with preoperative findings including retinal height at the fovea, total and inner layer cross-sectional macular area within 2 mm of the fovea, and preoperative BCVA ( , and , resp.). Multiple regression analysis revealed that the duration of macular detachment and total ...

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    14. Three-dimensional optic nerve head images using optical coherence tomography with a broad bandwidth, femtosecond, and mode-locked laser

      Three-dimensional optic nerve head images using optical coherence tomography with a broad bandwidth, femtosecond, and mode-locked laser

      Purpose The aim of this study was to demonstrate the fine laminar structure of the optic nerve head (ONH), in vivo, using a broad wavelength, ultra-high resolution, and optically coherent tomography (OCT) system. Methods This high-resolution OCT system, based on a 200 nm bandwidth spectrometer and an 8 femtosecond ultra-short, mode-locked, coherent laser light source, enabled in vivo cross-sectional ONH imaging with 2.0 μm axial resolution. A total of 300 optic disc B-scans, which consisted of 300 × 2048 pixels, were obtained in 10 μm steps. Three-dimensional images were rendered from these images to obtain n face images of the ...

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    15. Optical coherence tomography and visual evoked potentials combined use as monitoring tools in Multiple Sclerosis patients

      Optical coherence tomography and visual evoked potentials combined use as monitoring tools in Multiple Sclerosis patients

      In Multiple Sclerosis-MS, optical coherence tomography-OCT is used to measure retinal nerve fiber layer-RNFL thickness as a marker of axonal loss and visual evoked potentials-VEPs as an indicator of demyelination. However, no clear indications are available on their combined use in MS monitoring. 80 MS patients underwent neurological and neurophysiological evaluation with OCT and VEPs, with routine clinical and MRI monitoring for a mean period of 1 year. Additional OCT-VEPs follow-up was obtained in 50 patients. Comparing eyes with and without previous ON, VEP latency and RNFL thickness were respectively significantly higher (131.2 ms Vs 118.8 ms, p ...

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    16. Spectral-Domain Optical Coherence Tomography in Hydroxychloroquine Retinopathy

      Spectral-Domain Optical Coherence Tomography in Hydroxychloroquine Retinopathy

      In 2011, revised guidelines for screening chloroquine and hydroxychloroquine (HCQ) retinopathy recommended spectral-domain optical coherence tomography (SD OCT), fundus autofluorescence, or multifocal electroretinogram in addition to ophthalmologic examination and 10-2 perimetry. 1 To date, the qualitative features of SD OCT in chloroquine and HCQ retinopathy have been reported in <60 patients, most of whom had established retinopathy. Also, thinning of parafoveal retina has been documented, 2,3 occurring even when cross-sectional scans are equivocal.

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    17. Automatic segmentation of microcystic macular edema in OCT

      Automatic segmentation of microcystic macular edema in OCT

      Microcystic macular edema (MME) manifests as small, hyporeflective cystic areas within the retina. For reasons that are still largely unknown, a small proportion of patients with multiple sclerosis (MS) develop MME—predominantly in the inner nuclear layer. These cystoid spaces, denoted pseudocysts, can be imaged using optical coherence tomography (OCT) where they appear as small, discrete, low intensity areas with high contrast to the surrounding tissue. The ability to automatically segment these pseudocysts would enable a more detailed study of MME than has been previously possible. Although larger pseudocysts often appear quite clearly in the OCT images, the multi-frame averaging ...

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    18. Effects of Misalignments in the Retinal Nerve Fiber Layer Thickness Measurements with Spectral Domain Optical Coherence Tomography

      Effects of Misalignments in the Retinal Nerve Fiber Layer Thickness Measurements with Spectral Domain Optical Coherence Tomography

      Purpose . To investigate misalignments (MAs) on retinal nerve fiber layer thickness (RNFLT) measurements obtained with SD-OCT. Methods . This was a retrospective, observational, cross-sectional study. Twenty-seven healthy and 29 glaucomatous eyes of 56 individuals with one normal exam and another showing MA were included. MAs were defined as an improper alignment of vertical vessels in the en face image. MAs were classified in complete MA (CMA) and partial MA (PMA), according to their site: 1 (superior, outside the measurement ring (MR)), 2 (superior, within MR), 3 (inferior, within MR), and 4 (inferior, outside MR). We compared RNFLT measurements of aligned versus ...

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    19. Optical Coherence Tomography in Patients with Chiari I Malformation

      Optical Coherence Tomography in Patients with Chiari I Malformation

      Background/Aims . To evaluate optic nerve head with spectral domain optical coherence tomography (OCT) in patients with Chiari I malformation (CMI) compared to healthy controls. Methods . Cross-sectional study. OCT of the optic nerve head of 22 patients with CMI and 22 healthy controls was quantitatively analyzed. The healthy controls were matched for age and sex with the study population. Mean retinal nerve fiber layer (RNFL) thickness was calculated for both eyes; the mean thickness value was also registered for each quadrant and for each subfield of the four quadrants. Results . CMI patients showed a reduction of the RNFL thickness in ...

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    20. Three-Dimensional Vascular Imaging of Proliferative Diabetic Retinopathy by Doppler Optical Coherence Tomography

      Three-Dimensional Vascular Imaging of Proliferative Diabetic Retinopathy by Doppler Optical Coherence Tomography

      Purpose To evaluate the three-dimensional architecture of neovascularization in proliferative diabetic retinopathy using Doppler optical coherence tomography (OCT). Design Prospective, nonrandomized clinical trial. Methods Seventeen eyes of 14 patients with proliferative diabetic retinopathy were prospectively studied. Prototype Doppler OCT was used to evaluate the three-dimensional vascular architecture at vitreoretinal adhesions. Results Proliferative membranes were detected in all eyes with proliferative diabetic retinopathy by standard OCT images. Doppler OCT images detected blood flow by neovascularization of the disc in 12 eyes and neovascularization elsewhere in 11 eyes. Doppler OCT images showed the three-dimensional extent of new vessels at various stages of ...

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    21. Retinal Nerve Fiber Layer Defect Volume Deviation Analysis Using Spectral Domain Optical Coherence Tomography

      Retinal Nerve Fiber Layer Defect Volume Deviation Analysis Using Spectral Domain Optical Coherence Tomography

      Purpose: To report the retinal nerve fiber layer (RNFL) defect volume deviation according to structural RNFL loss in RNFL thickness maps Methods: RNFL defect is defined in RNFL thickness maps by the degree of RNFL loss. A 20% to 70% degree of RNFL loss was set with a 1% interval as the reference level for determining the boundary of RNFL defects. Each individual RNFL thickness map was compared to a normative database map and the region below the reference level was identified as an RNFL defect. The RNFL defect volume was calculated by summing the volumes of each pixel inside ...

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    22. Patient Characteristics Associated with Artifacts in Spectralis Optical Coherence Tomography Imaging of the Retinal Nerve Fiber Layer in Glaucoma

      Patient Characteristics Associated with Artifacts in Spectralis Optical Coherence Tomography Imaging of the Retinal Nerve Fiber Layer in Glaucoma

      Purpose To determine patient factors and eye conditions associated with artifacts in Spectralis optical coherence tomography (OCT) retinal nerve fiber layer (RNFL) scans. Design Retrospective cross-sectional study. Methods The prevalence of twelve artifact types were described in this review of 2313 eye scans from 1188 patients who underwent a complete eye exam with Spectralis OCT scanning during the period of September 2009 to July 2013. Generalized estimating equations model was utilized to analyze associations between increased artifact prevalence and 10 patient characteristics, which included age, sex, race, visual acuity, refractive error, astigmatism, cataract status, glaucoma staging, visual field reliability, and ...

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