1. Articles in category: Ophthalmology

    553-576 of 6065 « 1 2 ... 21 22 23 24 25 26 27 ... 251 252 253 »
    1. Frequency of abnormal retinal nerve fibre layer and ganglion cell layer SDOCT scans in healthy eyes and glaucoma suspects in a prospective longitudinal study

      Frequency of abnormal retinal nerve fibre layer and ganglion cell layer SDOCT scans in healthy eyes and glaucoma suspects in a prospective longitudinal study

      Background/aims To examine the frequency of abnormal retinal nerve fibre layer thickness (RNFLT) and ganglion cell complex (GCC) measurements among healthy and glaucoma suspect and preperimetric glaucoma (GSPPG) eyes in a prospective longitudinal study. Methods Normal and GSPPG eyes with ≥18 months follow-up were included. Spectral-domain optical coherence tomography (SDOCT) was performed annually in normal and biannually in GSPPG eyes. One eye was randomly selected for inclusion. RNFLT and GCC parameters with p>5% were classified as ‘within normal limits (WNL)’ and p<1% were classified as ‘outside normal limits (ONL)’. Results 23 normal and 74 GSPPG eyes were ...

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    2. Optical coherence tomography shows retinal abnormalities associated with optic nerve disease

      Optical coherence tomography shows retinal abnormalities associated with optic nerve disease

      Optical coherence tomography (OCT) of the macula in patients with primary optic neuropathy has revealed the presence of structural changes in the neurosensory retina in addition to the nerve fibre layer. Subretinal fluid has been documented in papilloedema and non-arteritic ischaemic optic neuropathy, and may account for decreased visual acuity in affected patients. Subretinal fluid has also been described from other causes of optic nerve head swelling including diabetic papillopathy and papillitis. Drugs used in the treatment of multiple sclerosis, such as corticosteroids and fingolimod can cause decreased vision due to central serous and cystoid macular oedema sometimes confused with ...

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      Mentions: Tufts University
    3. Optical coherence tomography in the preoperative and postoperative management of macular hole and epiretinal membrane

      Optical coherence tomography in the preoperative and postoperative management of macular hole and epiretinal membrane

      Optical coherence tomography (OCT) imaging plays an essential role in the diagnosis and treatment of macular diseases, including those of the vitreomacular interface. OCT enables accurate diagnosis and differentiation of full thickness macular hole, lamellar macular hole and epiretinal membrane, with or without the presence of vitreomacular adhesion. This information enables earlier diagnosis and treatment when necessary, and can guide the choice of therapy. OCT is useful to facilitate discussions with patients and manage the visual expectations. Postoperatively, OCT can be helpful to optimise patient comfort and visual outcomes. As the technology continues to improve, OCT will become increasingly critical ...

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    4. Optical Coherence Tomography Angiography of Optic Disc Perfusion in Glaucoma

      Optical Coherence Tomography Angiography of Optic Disc Perfusion in Glaucoma

      Purpose To compare optic disc perfusion between normal subjects and subjects with glaucoma using optical coherence tomography (OCT) angiography and to detect optic disc perfusion changes in glaucoma. Design Observational, cross-sectional study. Participants Twenty-four normal subjects and 11 patients with glaucoma were included. Methods One eye of each subject was scanned by a high-speed 1050-nm–wavelength swept-source OCT instrument. The split-spectrum amplitude-decorrelation angiography (SSADA) algorithm was used to compute 3-dimensional optic disc angiography. A disc flow index was computed from 4 registered scans. Confocal scanning laser ophthalmoscopy (cSLO) was used to measure disc rim area, and stereo photography was used ...

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    5. Choroidal Imaging with Use of Hand-held Spectral Domain Optical Coherence Tomography in Preterm and Term Infants

      Choroidal Imaging with Use of Hand-held Spectral Domain Optical Coherence Tomography in Preterm and Term Infants

      Purpose To determine whether choroidal imaging is feasible in preterm and term infants using an 840-nm portable spectral domain optical coherence tomography (SD-OCT) system without the use of enhanced-depth imaging techniques and to assess choroidal development by comparing choroidal thickness of preterm infants, term infants, and adults. Methods SD-OCT images were obtained from 86 preterm infants, 59 term infants, and nine adults using a portable SD-OCT system plus nine adults using a tabletop system. An unprocessed image across the macula from one randomly selected eye of each participant was selected for determination of whether the choroidal-scleral junction (CSJ) could be ...

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    6. Optical coherence tomography (OCT) imaging systems for use in ophthalmic applications

      Optical coherence tomography (OCT) imaging systems for use in ophthalmic applications

      Optical coherence tomography (OCT) imaging systems for imaging an eye are provided including a source having an associated source arm path and a reference arm having an associated reference arm path coupled to the source path, the reference arm path having an associated reference arm path length. A sample having an associated sample arm path coupled to the source arm and reference arm paths is provided. A reference arm path length adjustment module is coupled to the reference arm. The reference arm path length adjustment module is configured to automatically adjust the reference arm path length such that the reference ...

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    7. A New Paradigm for Glaucoma Diagnosis - Video By Dr. Joel S. Schuman, MD, FACS

      A New Paradigm for Glaucoma Diagnosis - Video By Dr. Joel S. Schuman, MD, FACS

      Glaucoma is the world’s second leading cause of blindness. In recognition of that, the World Glaucoma Association has named March 9-15 World Glaucoma Week. This is a week dedicated to encouraging everyone to find out if they are at risk. Joel S. Schuman, MD, FACS, and his team have been working on a way to diagnose glaucoma earlier. Dr. Schuman’s team has been using Optical Coherence Tomography (OCT) to detect early abnormalities in the optic nerve that occur before the change is detectable in the vision field. This development enables ophthalmologists to diagnose glaucoma earlier than ever before ...

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    8. Three-dimensional volumetric human meibomian gland investigation using polarization-sensitive optical coherence tomography

      Three-dimensional volumetric human meibomian gland investigation using polarization-sensitive optical coherence tomography

      In this study, polarization-sensitive optical coherence tomography (PS-OCT) capable of providing polarization contrasts such as phase retardation and degree of polarization uniformity (DOPU) was used for visualizing human meibomian glands (MGs) and investigating morphological characteristics of them. Especially, with the help of the DOPU contrast, MGs were exclusively extracted from the volumetric OCT image. In vivo PS-OCT measurements were performed on the upper eyelids of different age groups. From these measurements, different age-dependent aspects of the MG structure were also observed. Based on these observations, it can be inferred that the PS-OCT system has the potential for clinical diagnosis and ...

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    9. Stimulated penetrating keratoplasty using real-time virtual intraoperative surgical optical coherence tomography

      Stimulated penetrating keratoplasty using real-time virtual intraoperative surgical optical coherence tomography

      An intraoperative surgical microscope is an essential tool in a neuro- or ophthalmological surgical environment. Yet, it has an inherent limitation to classify subsurface information because it only provides the surface images. To compensate for and assist in this problem, combining the surgical microscope with optical coherence tomography (OCT) has been adapted. We developed a real-time virtual intraoperative surgical OCT (VISOCT) system by adapting a spectral-domain OCT scanner with a commercial surgical microscope. Thanks to our custom-made beam splitting and image display subsystems, the OCT images and microscopic images are simultaneously visualized through an ocular lens or the eyepiece of ...

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    10. Repeatability of in vivo 3D lamina cribrosa microarchitecture using adaptive optics spectral domain optical coherence tomography

      Repeatability of in vivo 3D lamina cribrosa microarchitecture using adaptive optics spectral domain optical coherence tomography

      We demonstrate the repeatability of lamina cribrosa (LC) microarchitecture for in vivo 3D optical coherence tomography (OCT) scans of healthy, glaucoma suspects, and glaucomatous eyes. Eyes underwent two scans using a prototype adaptive optics spectral domain OCT (AO-SDOCT) device from which LC microarchitecture was semi-automatically segmented. LC segmentations were used to quantify pore and beam structure through several global microarchitecture parameters. Repeatability of LC microarchitecture was assessed qualitatively and quantitatively by calculating parameter imprecision. For all but one parameters (pore volume) measurement imprecision was <4.7% of the mean value, indicating good measurement reproducibility. Imprecision ranged between 27.3% and ...

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    11. Development of a widefield phantom eye for retinal optical coherence tomography

      Development of a widefield phantom eye for retinal optical coherence tomography

      We report the design, manufacture and assessment of a phantom eye that can be used to measure the performance and accuracy of ophthalmic-OCT devices. We base our design on a wide-field schematic eye, R. Navarro, J. Opt. Soc. Am. A 2 (1985), to allow the assessment of device performance relative to ± 70° external field of view. We have fabricated the phantom eye and have verified the structural dimensions of the multi-material 3D-printed retinal targets using calibrated-OCT images.

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      Mentions: Optos
    12. Pilocarpine-induced dilation of Schlemm's canal and prevention of lumen collapse at elevated intraocular pressures in living mice visualized by OCT

      Pilocarpine-induced dilation of Schlemm's canal and prevention of lumen collapse at elevated intraocular pressures in living mice visualized by OCT

      Purpose:The goal was to assess effects of intraocular pressure (IOP) and pilocarpine-induced ciliary muscle contraction on conventional outflow pathway tissues in living anesthetized mice. Methods:IOP was controlled by intracameral cannulation of mouse eyes while imaging using spectral domain optical coherence tomography (SD-OCT). Time-lapse sagittal SD-OCT sections through Schlemm's canal (SC) were acquired while changing IOP stepwise between 10 and 45 mmHg. After topical application of 1% pilocarpine, the series of IOP steps and imaging were repeated. Effects of pilocarpine on IOP and outflow facility in living mice were verified by rebound tonometry and flow measurements at 3 ...

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    13. Quantitative Assessment of Retinal Nerve Fiber Layer Defect Depth Using Spectral-Domain Optical Coherence Tomography

      Quantitative Assessment of Retinal Nerve Fiber Layer Defect Depth Using Spectral-Domain Optical Coherence Tomography

      Purpose To assess quantitatively the depth of retinal nerve fiber layer (RNFL) defects using a Cirrus high-definition (HD) optical coherence tomography (OCT)–derived RNFL thickness deviation map. Design Prospective, cross-sectional study. Participants Three-hundred fifteen eyes with localized and diffuse RNFL defects of 315 glaucoma patients and 217 eyes of 217 healthy subjects. Methods For the glaucoma subjects, the severity of the RNFL defect was graded on red-free fundus photographs by 2 observers using a standardized protocol with a 3-level grading system. The RNFL defect depth on the RNFL thickness deviation map was expressed as an RNFL defect depth percentage index ...

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    14. Five-dimensional analysis of multi-contrast Jones matrix tomography of posterior eye

      Five-dimensional analysis of multi-contrast Jones matrix tomography of posterior eye

      Pixel clustering algorithm tailored to multi-contrast Jones matrix based optical coherence tomography (MC-JMT) is demonstrated. This algorithm clusters multiple pixels of MC-JMT in a five-dimensional (5-D) feature space which comprises dimensions of lateral space, axial space, logarithmic scattering OCT intensity, squared power of Doppler shift and degree of polarization uniformity. This 5-D clustering provides clusters of pixels, so called as superpixels. The superpixels are utilized as local regions for pixels averaging. The averaging decreases the noise in the measurement as preserving structural details of the sample. A simple decision-tree algorithm is applied to classified superpixels into some tissue types. This ...

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    15. Influence of automated disc margin determination on Stratus OCT optic nerve head measurements

      Influence of automated disc margin determination on Stratus OCT optic nerve head measurements

      Purpose: To analyze the influence of manual correction of the automatically determined edge of the optic nerve head (ONH) in optic disc measurements in cases in which the optical coherence tomography did not identify the disc limits correctly. Methods: The study included 127 eyes from 127 consecutive patients with glaucoma, suspects, and healthy individuals. In a retrospective analysis, eyes that underwent testing with the Stratus OCT (software version 4.0, Carl Zeiss Meditec, Dublin, CA, USA) Fast Optic Disc protocol were evaluated. Forty-seven eyes in which either the manual assignment was not necessary or the signal strength was below six ...

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    16. Long-term results of intravitreal ranibizumab for the treatment of retinal angiomatous proliferation and utility of an advanced RPE analysis performed using spectral-domain optical coherence tomography

      Long-term results of intravitreal ranibizumab for the treatment of retinal angiomatous proliferation and utility of an advanced RPE analysis performed using spectral-domain optical coherence tomography

      Purpose To report the results of 3-year follow-up examinations after intravitreal ranibizumab (IVR) injection for the treatment of retinal angiomatous proliferation (RAP) and to examine the utility of an advanced retinal pigment epithelium (RPE) analysis performed using spectral-domain optical coherence tomography (SD-OCT). Methods We retrospectively reviewed 17 treatment-naïve eyes in 14 patients (4 men, 10 women; age range 71–87 years; mean age 80 years) treated with IVR. All the patients received three consecutive monthly injections of 0.5 mg/0.05 mL of ranibizumab as an induction treatment. Retreatment was allowed if evidence of clinical deterioration was noted ...

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    17. Optical coherence tomography imaging of ocular and periocular tumours

      Optical coherence tomography imaging of ocular and periocular tumours

      Optical coherence tomography (OCT) has become pivotal in the practice of ophthalmology. Similar to other ophthalmic subspecialties, ophthalmic oncology has also incorporated OCT into practice. Anterior segment OCT (AS-OCT), ultra-high resolution OCT (UHR-OCT), spectral domain OCT (SD-OCT) and enhanced depth imaging OCT (EDI-OCT), have all been described to be helpful in the diagnosis, treatment planning and monitoring response of ocular and periocular tumours. Herein we discuss the role of OCT including the advantages and limitations of its use in the setting of common intraocular and adnexal tumours.

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      Mentions: Cleveland Clinic
    18. Duke University Receives NIH Grant for Studying Coherent Light Scattering for Early Detection of Retinal Disease

      Duke University Receives NIH Grant for Studying Coherent Light Scattering for Early Detection of Retinal Disease

      Duke University Received a 2014 NIH Grant for $189,624 for Studying Coherent Light Scattering for Early Detection of Retinal Disease. The principal investigator was Adam Wax. The program began in 2013 and ends in 2015. Below is a summary of the proposed work. The overall objective of this proposal is to develop a novel in vivo optical imaging system that will quantify structural biomarkers of retinal degenerative diseases. The state-of-the-art technology is measurement of the thickness of retina layers by spectral domain optical coherence tomography (SDOCT). However, while SDOCT can resolve histological layers, it lacks the resolution to measure ...

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    19. Comparison of relation between visual function index and retinal nerve fiber layer structure by optical coherence tomography among primary open angle glaucoma and primary angle closure glaucoma eyes

      Comparison of relation between visual function index and retinal nerve fiber layer structure by optical coherence tomography among primary open angle glaucoma and primary angle closure glaucoma eyes

      Purpose: To compare the visual field index (VFI) in primary open angle glaucoma (POAG) and primary angle closure glaucoma (PACG) eyes, and to study the correlation with disc variables on optical coherence tomography (OCT) in all stages of severity. Materials and Methods: Thirty POAG and PACG underwent Humphrey visual field 24-2 along with detailed examination. They also underwent stratus OCT imaging of the optic nerve and retinal nerve fiber layer (RNFL). The correlation of VFI with RNFL thickness was compared in POAG and PACG. Results: The VFI significantly differed between POAG and PACG, with POAG eyes apparently having a better ...

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    20. Optical Coherence Tomography (Textbook)

      Optical Coherence Tomography (Textbook)

      Because of its many advantages optical coherence tomography (OCT) has revolutionized the way in which retinal diseases are screened and managed and how treatments are monitored. In this volume the latest developments and findings are presented by experts in their respective fields. After a short introduction covering the available equipment and the basic techniques, the imaging features of various pathological findings in retinal diseases are presented. The topics cover the outer layers including new modalities for choroid imaging, out-layer diseases such as the various types of macular degeneration, retinal diseases such as diabetic retinopathy and vascular occlusion, and retina and ...

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