1. Articles in category: Ophthalmology

    1-24 of 6060 1 2 3 4 ... 251 252 253 »
    1. Novel insights provided by spectral-domain coherent tomography in pediatric ophthalmology

      Novel insights provided by spectral-domain coherent tomography in pediatric ophthalmology

      Tilted disk syndrome (TDS) is observed in approximately 1 % to 2 % of the population. This percentage appears to be highly variable according to the clinical and imaging features retained for establishing the accurate diagnosis. It is of paramount importance to distinguish isolated tilted optic disk from TDS. This syndrome has a number of alternative nomenclatures such as the nasal fundus ectasia syndrome, inversion of the optic disk, inverse myopia, and dysversion of the optic disk. TDS may be a variant of colobomatous defects. The definition of TDS has often been inaccurate in many studies which did not take account of ...

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    2. Repeatability of peripapillary retinal nerve fiber layer and inner retinal thickness among 2 spectral domain optical coherence tomography devices

      Repeatability of peripapillary retinal nerve fiber layer and inner retinal thickness among 2 spectral domain optical coherence tomography devices

      PURPOSE. To compare measurement of macular inner retina and peripapillary retinal nerve fiber layer (pRNFL) thickness using 2 spectral-domain optical coherence tomography (OCT) devices in glaucoma patients, patients with ocular hypertension, idiopathic and atypical Parkinson's disease and healthy controls. METHODS. One-hundred seventy-one eyes of 146 participants underwent successful pRNFL and macular scanning and automated measurement of ganglion cell layer + inner plexiform layer (GCL-IPL) using Cirrus® HD-OCT or retinal nerve fiber layer + ganglion cell layer + inner plexiform layer (RNFL-GCL-IPL) using RTVue-100®. Macular RNFL was added to the GCL-IPL thickness measured by Cirrus and was compared to the RNFL-GCL-IPL thickness of ...

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    3. Effect of elevated intraocular pressure on the thickness changes of cat laminar and prelaminar tissue using optical coherence tomography

      Effect of elevated intraocular pressure on the thickness changes of cat laminar and prelaminar tissue using optical coherence tomography

      The aim of this study was to examine shape the changes of the lamina cribrosa (LC) under different intraocular pressures (IOPs) with different periods. Images of the optic nerve head were obtained using enhanced depth imaging spectral domain optical coherence tomography (EDI SD-OCT). After an initial scan of the IOP at native pressure, subsequent scanning was taken when the IOP values reached 40, 60, 80 and 100 mm Hg. Then scans continued with the IOP maintained at 100 mm Hg for 1 hour, 2 hours, 3 hours and 4 hours. The thicknesses of the LC and prelaminar tissue were measured ...

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    4. In Vivo Three-Dimensional Characterization of the Healthy Human Lamina Cribrosa with Adaptive Optics Spectral-Domain Optical Coherence Tomography

      In Vivo Three-Dimensional Characterization of the Healthy Human Lamina Cribrosa with Adaptive Optics Spectral-Domain Optical Coherence Tomography

      Purpose: To characterize the in vivo 3D lamina cribrosa (LC) microarchitecture of healthy eyes using adaptive optics spectral-domain optical coherence tomography (AO-SDOCT). Methods: One randomly selected eye from each of 18 healthy subjects was scanned with Cirrus HD-OCT and AO-SDOCT centered on the optic nerve head. LC microarchitecture, imaged by the later device, was semi-automatically segmented and quantified for connective tissue volume fraction (CTVF), beam thickness, pore diameter, pore area and pore aspect ratio. The LC was assessed in central and peripheral regions of equal areas, quadrants and with depth. A linear mixed-effects model weighted by the fraction of visible ...

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    5. Accommodation-induced variations in retinal thickness measured by spectral domain optical coherence tomography

      Accommodation-induced variations in retinal thickness measured by spectral domain optical coherence tomography

      To research retinal stretching or distortion with accommodation, accommodation-induced changes in retinal thickness (RT) in the macular area were investigated in a population of young adults ( n = 23 ) by using a dual-channel spectral domain optical coherence tomography (SD-OCT) system manufactured in-house for this study. This dual-channel SD-OCT is capable of imaging the cornea and retina simultaneously with an imaging speed of 24 kHz A-line scan rate, which can provide the anatomical dimensions of the eye, including the RT and axial length. Thus, the modification of the RT with accommodation can be calculated. A significant decrease in the RT ( 13.50 ...

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    6. Corneal assessment technologies: Current status

      Corneal assessment technologies: Current status

      There are now many devices that acquire data about the cornea: shape, power, pachymetry at any desired point of the cornea, corneal hysteresis, flap thickness (in LASIK procedures), endothelial cell count and morphology, and so forth. We review the literature on corneal assessment techniques and devices available in clinical practice. Specifically, we discuss slit lamp biomicroscopy, specular microscopy, ultrasound pachymetry, confocal microscopy, very-high-frequency digital ultrasound biomicroscopy, optical coherence tomography, Placido disk-based keratoscopy, slit-scanning elevation topography, Scheimpflug imaging, and dynamic applanation procedures—all of which can be used to assess the morphology of the cornea. In addition, we present a critical ...

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    7. Treatment Outcomes and Spectral Domain Optical Coherence Tomography Findings of Eyes with Symptomatic Vitreomacular Adhesion Treated with Intravitreal Ocriplasmin

      Treatment Outcomes and Spectral Domain Optical Coherence Tomography Findings of Eyes with Symptomatic Vitreomacular Adhesion Treated with Intravitreal Ocriplasmin

      Purpose To determine treatment outcomes of intravitreal ocriplasmin in symptomatic vitreomacular adhesion Design Retrospective interventional case series Methods: Setting Private practice Study population 35 eyes (35 subjects) with symptomatic vitreomacular adhesion Intervention/Observation Intravitreal ocriplasmin injection from February-November 2013 Main Outcome Measure Vitreomacular adhesion resolution rate. Secondary endpoints included post-injection visual acuity, and rates of outer retinal attenuation and full thickness macular hole (MH) closure. Results The 35 subjects included were of mean age 69 years, 66% female, and 71% phakic. Eleven (31%) cases had macular co-morbidities. Average adhesion diameter was 571 micrometers (μm), with mean 7.9 months duration ...

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    8. Macular Thickness Measurements in Normal Eyes Using Spectral Domain Optical Coherence Tomography

      Macular Thickness Measurements in Normal Eyes Using Spectral Domain Optical Coherence Tomography

      BACKGROUND AND OBJECTIVE: Knowledge of the macular thickness in a normal population is important for the evaluation of pathological macular change. The purpose of this study was to define and measure macular thickness in normal eyes using spectral domain optical coherence tomography (OCT). PATIENTS AND METHODS: Fifty eyes from 50 normal subjects (29 men and 21 women, aged 22 to 68 years) were scanned with a prototype Cirrus HD-OCT system (5 µm axial resolution) (Carl Zeiss Meditec, Inc.). The proprietary Cirrus segmentation algorithm was used to produce retinal thickness maps, which were then averaged over 9 regions defined by a ...

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    9. Influence of choroidal thickness on subfoveal choroidal thickness measurement repeatability using enhanced depth imaging optical coherence tomography

      Influence of choroidal thickness on subfoveal choroidal thickness measurement repeatability using enhanced depth imaging optical coherence tomography

      Purpose To determine the influence of choroidal thickness (CT) and image setting on repeatability of subfoveal choroidal thickness (SFCT) manual measurement using enhanced depth imaging optical coherence tomography (EDI-OCT). Methods This retrospective study included 189 eyes from 189 adults. Two observers (A and B) measured the SFCT from 1   :   1 micron and 1   :   1 pixel images for evaluation of interobserver repeatability. Observer A performed a single additional measurement for intraobserver repeatability. Results The mean age was 45.1±11.1 years. The mean SFCT from 1   :   1 pixel and 1   :   1 micron images were 315.3±89.2 and 312 ...

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    10. New York University School of Medicine Receives 2014 NIH Grant to Study Hyperspectral Imaging of the Normal and Age-Related Macular Degeneration Fundus

      New York University School of Medicine Receives  2014 NIH Grant to Study Hyperspectral Imaging of the Normal and Age-Related Macular Degeneration Fundus

      A team with world-class expertise in ophthalmic disease, imaging, retinal pathology, and biomedical engineering will utilize hyperspectral imaging to provide, for the first time, in vivo molecular probing, validated with histopathologic correlation, of age-related macular degeneration (AMD). Their system, a specially modified fundus camera harnessed to cutting-edge biomedical image analysis techniques, will revolutionize the field by identifying the distribution and spectral signature of the various chromophores and fluorophores associated with AMD lesions. Drusen, the hallmark lesions of AMD, are biochemically heterogeneous and are key to understanding this disease. However, their composition cannot be determined in vivo with even the current ...

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    11. Dependability of Posterior-Segment Spectral Domain Optical Coherence Tomography for Measuring Central Corneal Thickness

      Dependability of Posterior-Segment Spectral Domain Optical Coherence Tomography for Measuring Central Corneal Thickness

      Purpose: The aim of this study was to assess the intersession and interobserver reliability of central corneal thickness (CCT) measurements using a posterior-segment spectral domain optical coherence tomography (SD-OCT). Methods: Sixty patients were examined with a posterior-segment SD-OCT system (Topcon 3D-OCT). To analyze intersession reproducibility, 1 examiner measured CCT in 60 eyes 2 times 1 week apart, and to study interobserver reproducibility, a second examiner obtained another measurement during the first session. Within-subject reproducibility, coefficient of reproducibility (CR), and intraclass correlation coefficients (ICC) were calculated. Agreement between Topcon 3D OCT and ultrasound pachymetry (USP) was also assessed. Results: Posterior-segment SD-OCT ...

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    12. Assessment of Retinal Alterations after Intravitreal Ocriplasmin with Spectral Domain-Optical Coherence Tomography

      Assessment of Retinal Alterations after Intravitreal Ocriplasmin with Spectral Domain-Optical Coherence Tomography

      Ocriplasmin (Jetrea, Thrombogenics, Leuven, Belgium) was recently approved by the United States Food and Drug Administration for the treatment of symptomatic vitreomacular traction (VMT). The MIVI-TRUST phase III randomized, controlled trials revealed that intravitreal ocriplasmin had superior efficacy for VMT resolution compared with placebo vehicle injection. 1 Qualitative identification of outer retinal changes after ocriplasmin injection that were not previously recognized in the MIVI-TRUST trials have recently been described.

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    13. Optical Coherence Tomography Imaging of the Proximal Lacrimal System

      Optical Coherence Tomography Imaging of the Proximal Lacrimal System

      Abstract Introduction: There are currently no routinely used imaging modalities for the proximal lacrimal system. Optical Coherence Tomography (OCT) is a safe and non-invasive method of high resolution cross-sectional imaging of tissue microstructures using infra-red radiation. In this study we investigate whether OCT may be used to image the punctum and proximal canaliculus. Methods: A cohort of healthy subjects with normal ocular anatomy and no symptoms of epiphora were prospectively invited to enrol. Spectral OCT images of the lower punctae were captured with a Topcon 3D Optical Coherence Tomography 2000 machine. Measurements were made of the maximal punctal diameter, canalicular ...

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    14. Optical coherence tomography appears valuable for tracking MS patients over time

      Optical coherence tomography appears valuable for tracking MS patients over time

      Retinal changes over time mirror global central nervous system processes in patients with multiple sclerosis, according to findings from a longitudinal study comparing optical coherence tomography and magnetic resonance imaging findings. The results validate optical coherence tomography (OCT) measures for both clinical monitoring of patients, and as an outcome measure in clinical trials, and could have implications that reach beyond MS, Dr. Shiv Saidha said at the joint meeting of the European and Americas committees for Treatment and Research in Multiple Sclerosis. In 107 multiple sclerosis (MS) patients with a mean age of 44 years and median disease duration of ...

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    15. Fully automated detection of diabetic macular edema and dry age-related macular degeneration from optical coherence tomography images

      Fully automated detection of diabetic macular edema and dry age-related macular degeneration from optical coherence tomography images

      We present a novel fully automated algorithm for the detection of retinal diseases via optical coherence tomography (OCT) imaging. Our algorithm utilizes multiscale histograms of oriented gradient descriptors as feature vectors of a support vector machine based classifier. The spectral domain OCT data sets used for cross-validation consisted of volumetric scans acquired from 45 subjects: 15 normal subjects, 15 patients with dry age-related macular degeneration (AMD), and 15 patients with diabetic macular edema (DME). Our classifier correctly identified 100% of cases with AMD, 100% cases with DME, and 86.67% cases of normal subjects. This algorithm is a potentially impactful ...

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    16. Bioptigen Introduces Deep Imaging OCT System for Contact Lens Metrology

      Bioptigen Introduces Deep Imaging OCT System for Contact Lens Metrology

      Bioptigen announced today the availability of a newly developed deep imaging OCT system for the optical device metrology and pre-clinical ophthalmic research markets. The Envisu S4410 SDOCT for Contact Lens Metrology is designed for non-destructive, non-contact, full immersion measurements for standard and high complexity contact lens, IOL structures, and donor tissues. The metrology system allows imaging of a complete contact lens immersed in a hydration bath (saline), automated segmentation of anterior and posterior surfaces, and quantification of curvatures across both surfaces. The system delivers 5 um axial pixel resolution, 11 mm scan depth in saline, and a full 20mm lateral ...

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      Mentions: Bioptigen
    17. Automated retinal layers segmentation in SD-OCT images using dual-gradient and spatial correlation smoothness constraint

      Automated retinal layers segmentation in SD-OCT images using dual-gradient and spatial correlation smoothness constraint

      Automatic segmentation of retinal layers in spectral domain optical coherence tomography (SD-OCT) images plays a vital role in the quantitative assessment of retinal disease, because it provides detailed information which is hard to process manually. A number of algorithms to automatically segment retinal layers have been developed; however, accurate edge detection is challenging. We developed an automatic algorithm for segmenting retinal layers based on dual-gradient and spatial correlation smoothness constraint. The proposed algorithm utilizes a customized edge flow to produce the edge map and a convolution operator to obtain local gradient map in the axial direction. A valid search region ...

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    18. Study of cystoid macular edema by optical coherent tomography following uneventful cataract surgery

      Study of cystoid macular edema by optical coherent tomography following uneventful cataract surgery

      The objective of this paper is to study the incidence of cystoid macular edema (CME) using optical coherence tomography (OCT) following uneventful small incision cataract surgery (SICS) and phacoemulsification. This was a descriptive, prospective study where 200 patients undergoing cataract surgery were randomly divided into two groups over a period of 1 year. Patients undergoing uneventful small incision cataract surgery were included in group I and patient undergoing uneventful phacoemulsification were included in group II, with 100 patients in each group. Preoperative assessment included best corrected visual acuity, detailed anterior segment and posterior segment evaluation, and intraocular pressure measurement. Macular ...

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    19. Retinal Regeneration Following OCT-guided Laser Injury in Zebrafish

      Retinal Regeneration Following OCT-guided Laser Injury in Zebrafish

      Purpose: Establish a focal injury/regeneration model in zebrafish using laser photocoagulation guided by optical coherence tomography (OCT). Methods: Adult zebrafish were imaged by OCT and confocal scanning laser ophthalmoscopy (cSLO) in room air through a contact lens. Using a beam combiner, 532nm laser photocoagulation was applied using the OCT C-scan image for targeting. Laser spots of 42-47mW were delivered to the retina. At multiple intervals post-injury, fish were imaged using both OCT and cSLO to follow the progression of each lesion. Histologic sections and TUNEL staining were performed to monitor the injury response. Results: Round lesions (26057 ± 621μm2 ...

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    20. SPECTRAL DOMAIN OPTICAL COHERENCE TOMOGRAPHY IN THE EVALUATION AND MANAGEMENT OF INFECTIOUS RETINITIS

      SPECTRAL DOMAIN OPTICAL COHERENCE TOMOGRAPHY IN THE EVALUATION AND MANAGEMENT OF INFECTIOUS RETINITIS

      Purpose: To describe spectral domain optical coherence tomography (SD-OCT) findings of infectious retinitis, including affected layer of retinal involvement, changes at the vitreoretinal interface, and response to therapy. Methods: Observational case series. A retrospective review of five patients with infectious retinitis: one with toxoplasmosis, three with herpetic retinitis secondary to cytomegalovirus, and one with herpetic retinitis secondary to varicella zoster virus. Each patient underwent a complete ophthalmologic examination, fundus photography, and SD-OCT imaging (Heidelberg Spectralis; Heidelberg Engineering, Heidelberg, Germany) of the affected retina at the initial visit with serial fundus photography and SD-OCT imaging at follow-up visits. Approval was obtained ...

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    21. OCT 3-D surface topography of isolated human crystalline lenses

      OCT 3-D surface topography of isolated human crystalline lenses

      Quantitative 3-D Optical Coherence Tomography was used to measure surface topography of 36 isolated human lenses, and to evaluate the relationship between anterior and posterior lens surface shape and their changes with age. All lens surfaces were fitted to 6th order Zernike polynomials. Astigmatism was the predominant surface aberration in anterior and posterior lens surfaces (accounting for ~55% and ~63% of the variance respectively), followed by spherical terms, coma, trefoil and tetrafoil. The amount of anterior and posterior surface astigmatism did not vary significantly with age. The relative angle between anterior and posterior surface astigmatism axes was on average 36 ...

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