1. Articles in category: Ophthalmology

    553-576 of 6318 « 1 2 ... 21 22 23 24 25 26 27 ... 262 263 264 »
    1. OCT in Zero Gravity

      OCT in Zero Gravity

      Heidelberg Engineering’s annual 2014 Xtreme Research Award was presented to the NASA Ocular Health Study during the recent award ceremony in Orlando, Florida. Over 200 scientists who were in the city for the annual meeting of the Association for Research in Vision and Ophthalmology (ARVO) gathered for the event. Dr. Nimesh Patel, Assistant Professor at the University of Houston, College of Optometry and a consultant to NASA accepted the award and presented the award lecture. In the presentation, entitled “OCT in Zero G,” Dr. Patel provided details about the use of SPECTRALIS ® Optical Coherence Tomography (OCT) on board the ...

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    2. Nicotine Accelerates Diabetes-Induced Retinal Changes

      Nicotine Accelerates Diabetes-Induced Retinal Changes

      Purpose : To investigate the effects of nicotine on retinal alterations in early-stage diabetes in an established rodent model. Materials and Methods : Sprague–Dawley rats were examined using a combination of confocal scanning laser ophthalmoscopy and spectral domain optical coherence tomography to determine changes in retinal structure in response to nicotine exposure, diabetes and the combined effects of nicotine and diabetes . Diabetes was induced by a single injection of 65 mg/kg streptozotocin and nicotine injections were administered subcutaneously daily. Retinal thickness in the superior, inferior, nasal and temporal quadrants were determined based on the spectral domain optical coherence tomography (SD-OCT ...

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    3. Choroidal Thickness in Ocular Sarcoidosis during Quiescent Phase Using Enhanced Depth Imaging Optical Coherence Tomography

      Choroidal Thickness in Ocular Sarcoidosis during Quiescent Phase Using Enhanced Depth Imaging Optical Coherence Tomography

      Purpose : To evaluate the choroidal thickness in patients with ocular sarcoidosis during quiescent phase using enhanced depth imaging optical coherence tomography (EDI-OCT) and comparing it with normal subjects. Method : Eighteen eyes of 9 patients with ocular sarcoidosis (8 women, 1 man, mean age: 59.12 ± 18.49 years) were enrolled in this study. Their subfoveal choroidal thickness was measured using EDI-OCT in the quiescent phase of uveitis, and compared with the age-, sex-, and spherical equivalent-matched normal subjects (6 women, 3 men, mean age: 59.6 ± 14.22 years). Results : The mean subfoveal choroidal thickness was 281.76 ± 88.1 ...

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    4. Choroidal Haller's and Sattler's Layer Thickness Measurement Using 3-Dimensional 1060-nm Optical Coherence Tomography

      Choroidal Haller's and Sattler's Layer Thickness Measurement Using 3-Dimensional 1060-nm Optical Coherence Tomography

      Objectives To examine the feasibility of automatically segmented choroidal vessels in three-dimensional (3D) 1060-nmOCT by testing repeatability in healthy and AMD eyes and by mapping Haller's and Sattler's layer thickness in healthy eyes Methods Fifty-five eyes (from 45 healthy subjects and 10 with non-neovascular age-related macular degeneration (AMD) subjects) were imaged by 3D-1060-nmOCT over a 36°x36° field of view. Haller's and Sattler's layer were automatically segmented, mapped and averaged across the Early Treatment Diabetic Retinopathy Study grid. For ten AMD eyes and ten healthy eyes, imaging was repeated within the same session and on another ...

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    5. Evaluation of congenital excavated optic disc anomalies with spectral-domain and swept-source optical coherence tomography

      Evaluation of congenital excavated optic disc anomalies with spectral-domain and swept-source optical coherence tomography

      Purpose To investigate the anatomic characteristics of congenital excavated optic disc anomalies by using fundus photography, spectral-domain optical coherence tomography (SD-OCT), and swept-source optical coherence tomography (SS-OCT). Methods Fourteen eyes from 13 patients with congenital excavated optic disc anomalies underwent a complete ophthalmologic examination that included best-corrected visual acuity evaluation, fundus photography, and SD-OCT. SS-OCT was performed in cases of peripapillary staphyloma cases in which the excavation depth could not be detected with SD-OCT. On the basis of the funduscopic and OCT findings, patients were classified as morning glory syndrome, optic disc coloboma, or peripapillary staphyloma. Results Seven eyes with ...

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    6. Automatic Biometry of the Anterior Segment During Accommodation Imaged by Optical Coherence Tomography

      Automatic Biometry of the Anterior Segment During Accommodation Imaged by Optical Coherence Tomography

      Objective: To test accuracy and repeatability of a software algorithm that performs automatic biometry of the anterior segment of the human eye imaged with long scan depth optical coherence tomography (OCT). Methods: The ocular anterior segment imaging was performed with custom-built long scan depth OCT. An automatic software algorithm including boundary segmentation, image registration, and optical correction was developed for fast and reliable biometric measurements based on the OCT images. The boundary segmentation algorithm mainly used the gradient information of images and applied the shortest path search based on the dynamic programming to optimize the edge finding. The automatic algorithm ...

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    7. Measurement of Anterior Scleral Curvature Using Anterior Segment OCT

      Measurement of Anterior Scleral Curvature Using Anterior Segment OCT

      Purpose: To investigate and validate methods for measuring the radius of anterior scleral curvature using anterior segment optical coherence tomography images. Methods: Twenty-four volunteers were enrolled in this study. Anterior segment optical coherence tomography images, centered on horizontal/vertical limbus, including adjacent anterior sclera, were obtained in addition to conventional images centered on the optical axis. Central horizontal, nasal, and temporal optical coherence tomography images were consolidated to a new image for subsequent analyses. The reference points of limbal surface and three scleral points were marked nasally and temporally. The radius of a best-fit circle to the six scleral points ...

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    8. Multimodality Imaging Methods for Assessing Retinoblastoma Orthotopic Xenograft Growth and Development

      Multimodality Imaging Methods for Assessing Retinoblastoma Orthotopic Xenograft Growth and Development

      Genomic studies of the pediatric ocular tumor retinoblastoma are paving the way for development of targeted therapies. Robust model systems such as orthotopic xenografts are necessary for testing such therapeutics. One system involves bioluminescence imaging of luciferase-expressing human retinoblastoma cells injected into the vitreous of newborn rat eyes. Although used for several drug studies, the spatial and temporal development of tumors in this model has not been documented. Here, we present a new model to allow analysis of average luciferin flux ( ) through the tumor, a more biologically relevant parameter than peak bioluminescence as traditionally measured. Moreover, we monitored the spatial ...

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    9. Evaluation of patients with diffuse unilateral subacute neuroretinitis by spectral domain optical coherence tomography with enhanced depth imaging

      Evaluation of patients with diffuse unilateral subacute neuroretinitis by spectral domain optical coherence tomography with enhanced depth imaging

      Background: The purpose of this study was to determine the value of spectral domain ­optical coherence tomography (SD-OCT) in assessing patients with diffuse unilateral subacute neuroretinitis (DUSN). Methods: This was an observational case series with clinical imaging correlation performed at the Retina and Vitreous Institute of Londrina and State University of Londrina, Paraná, Brazil. The series comprised ten consecutive patients with a confirmed diagnosis of DUSN, ie, seven patients with late-stage disease and three with early-stage disease, who were assessed by SD-OCT for mean macular, retinal nerve fiber layer, and choroidal thickness using enhanced depth imaging software. Results: Comparing the ...

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    10. Relationship between spectral-domain optical coherence tomography and standard automated perimetry in healthy and glaucoma patients

      Relationship between spectral-domain optical coherence tomography and standard automated perimetry in healthy and glaucoma patients

      Objective: To evaluate the relationship between spectral-domain optical coherence tomography (OCT) and standard automated perimetry (SAP) in healthy and glaucoma individuals. Methods: The sample comprised 338 individuals divided into 2 groups according to intraocular pressure and visual field outcomes, regardless of optic disc appearance. All participants underwent imaging of the optic nerve head (ONH) with the Cirrus OCT (Carl Zeiss Meditec, Dublin, CA) and SAP (Humphrey Field Analyzer, Carl Zeiss Meditec; 24-2 SITA Standard strategy). Only one eye per participant was randomly selected. Pearson correlations were calculated between threshold sensitivity values of SAP (converted to linear scale) and OCT parameters ...

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    11. Image Processing and Information Theory Analysis for Glaucoma OCT Images

      Image Processing and Information Theory Analysis for Glaucoma OCT Images

      Glaucoma is a group of optic nerve disease with progressive structural changes leading to loss of visual function. A careful examination and detection of changes in the optic nerve is the key to early diagnosis of glaucoma. Optical Coherence Tomography (OCT) is one of the known techniques of diagnosis of glaucoma. The patients’ eyes are scanned and sub-surface images are captured from optical nerves. Captured OCT images usually suffer from noise and therefore image enhancement techniques can help doctors in better analysis of OCT images and diagnosis of glaucoma. In this paper, we propose three successful algorithms for enhancing the ...

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    12. Study of Retinal Nerve Fibre Layer Thickness in Type 2 Diabetes Mellitus by 3-Dimensional Optical Coherence Tomography from Eastern India

      Study of Retinal Nerve Fibre Layer Thickness in Type 2 Diabetes Mellitus by 3-Dimensional Optical Coherence Tomography from Eastern India

      Three dimensional optical coherence tomography (OCT) is a novel technique to diagnose retinal disorders. In diabetes, loss of retinal neurons is said to be an early event. We did a small pilot study from Eastern India to find the usefulness of OCT in detecting changes in retinal nerve fibre layer (RNFL) in diabetics. We selected adult type 2 diabetics without overt retinopathy. Patients aged more than 60 or with pre-existing problems like glaucoma or vasculitis were excluded. RNFL thickness was measured using HRA-OCT Spectralis analyser. A 12º area around optic nerve head was analysed and depth of each quadrant was ...

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    13. Refractive index measurement of the mouse crystalline lens using optical coherence tomography

      Refractive index measurement of the mouse crystalline lens using optical coherence tomography

      In recent years, there has been a growing interest for using mouse models in refractive development and myopia research. The crystalline lens is a critical optical component of the mouse eye that occupies greater than 50% of the ocular space, and significant increases in thickness with age. However, changes in refractive index of the mouse crystalline lens are less known. In this study, we examined the changes in thickness and refractive index of the mouse crystalline lens for two different strains, wild-type (WT) and a nyx mutant ( nob ) over the course of normal visual development or after form deprivation. Refractive ...

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      Mentions: Emory University
    14. Can an automated algorithm identify choriocapillaris in 2D-optical coherence tomography images?

      Can an automated algorithm identify choriocapillaris in 2D-optical coherence tomography images?

      This editorial considers the problem of automatic identification of choriocapillaris in 2D-optical coherence tomography images. Firstly, the major challenges in automating the process are presented. Subsequently, the authors present an overview of current methods in the automatic segmentation of 2D-optical coherence tomography images. Lastly, the authors close with a discussion on a recent algorithm for the automated identification of choriocapillaris based on the identification of the retinal pigment epithelial layer and the region in its immediate neighborhood, and its capabilities. 

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    15. Effect of Intraocular Pressure and Anisotropy on the Optical Properties of the Cornea: A Study Using Polarization Sensitive Optical Coherence Tomography

      Effect of Intraocular Pressure and Anisotropy on the Optical Properties of the Cornea: A Study Using Polarization Sensitive Optical Coherence Tomography

      Purpose: We hypothesize that because of the anisotropic properties of the cornea, there should be a nonuniform change in birefringence with an increase in intraocular pressure (IOP). In this in vitro study, anisotropic properties, stress distribution within the cornea, and the effect of IOP on changes in stress level were investigated. Design: Button inflation tests for deformation with polarization sensitive optical coherence tomography were used to demonstrate optical and material anisotropy on ex vivo human corneas. Methods: Inflation tests were performed on human donor corneoscleral rims. Using a turntable and hydrostatic column, each corneoscleral rim was subjected to a hydrostatic ...

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    16. Ophthalmologic image display apparatus, ophthalmologic image display method, program, and storage medium

      Ophthalmologic image display apparatus, ophthalmologic image display method, program, and storage medium

      An ophthalmologic image display apparatus for displaying information about an eye includes an input unit configured to input a tomographic image of the eye, an acquisition unit configured to acquire diagnostic supporting information associated with positional information about the tomographic image of the eye, a processing unit configured to perform processing for assigning a voxel value to volume data constituting the tomographic image based on a reflection intensity value indicating the tomographic image and the diagnostic supporting information, and a display control unit configured to cause a display unit to display an image processed by the processing unit.

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    17. Article for use in an OCT-method and intraocular lens

      Article for use in an OCT-method and intraocular lens

      An article for use in an OCT method, the article comprising a solid substrate and nanoparticles dispersed in or on the substrate in at least one light transmissive portion of the article such that the nanoparticles result in an increased extinction of the light transmissive portion along a transmission direction of the light transmissive portion compared to the substrate being free of nanoparticles. The extinction of the light transmissive portion along the transmission direction is less than 6, wherein the extinction is defined as a negative decadic logarithm of a ratio of an intensity of light which is transmitted through ...

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    18. Haag-Streit Surgical Intraoperative OCT "iOCT" Product Brochure

      Haag-Streit Surgical Intraoperative OCT "iOCT" Product Brochure

      HAAG-STREIT SURGICAL is pleased to introduce the world‘s first intraoperative OCT system, developed by OPMedT. An OCT camera is integrated into the high class operating microscope HS Hi-R NEO 900A NIR and its mounting system. OCT scans of the eye’s anterior and posterior segments are performed live during surgery, thus increasing the patient’s safety and improving quality control mechanisms for the surgeon. Discover more details than with a standard surgical microscope and enhance your performance! To see product brochure click HERE.

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      Mentions: Haag-Streit OPMedT
    19. Haag-Streit Surgical Interoperative Optical Coherence Tomography System

      Haag-Streit Surgical Interoperative Optical Coherence Tomography System

      HAAG-STREIT SURGICAL's integrated iOCT system has been developed for intraoperative optical coherence tomography (iOCT™). It is non-invasive, and permits contact-free imaging for imaging structures and layers within the tissue. The iOCT's advantages find confirmation again and again among users and industry professionals: "When making corneal incisions, the iOCT shows you perfectly how the cornea is cleaved. This feedback allows you to adapt your technique to make a more water-tight incision. You can react to unexpected incidents immediately and avoid further complications.“, states Professor Peter Stalmans from the University of Leuven, Belgium. Professor Peter Stalmans from the University of ...

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    20. Spectral domain optical coherence tomography in patients after successful management of postoperative endophthalmitis following cataract surgery by pars plana vitrectomy

      Spectral domain optical coherence tomography in patients after successful management of postoperative endophthalmitis following cataract surgery by pars plana vitrectomy

      Background Acute severe postoperative endophthalmitis may lead to severe vision loss. The aim of this study was the analysis of macular microstructure imaged by spectral domain optical coherence tomography in patients after pars plana vitrectomy due to postcataract endophthalmitis. Methods A cross sectional study was carried out in 17 patients who had cataract surgery in both eyes and underwent unilateral pars plana vitrectomy due to postcataract endophthalmitis. Postoperative best corrected visual acuity was determined in both eyes. Evaluation of macular thickness, macular volume, peripapillary retinal nerve fiber layer thickness and choroidal thickness using enhanced depth imaging technique was performed by ...

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    21. Probabilistic intra-retinal layer segmentation in 3-D OCT images using global shape regularization

      Probabilistic intra-retinal layer segmentation in 3-D OCT images using global shape regularization

      With the introduction of spectral-domain optical coherence tomography (OCT), resulting in a significant increase in acquisition speed, the fast and accurate segmentation of 3-D OCT scans has become evermore important. This paper presents a novel probabilistic approach, that models the appearance of retinal layers as well as the global shape variations of layer boundaries. Given an OCT scan, the full posterior distribution over segmentations is approximately inferred using a variational method enabling efficient probabilistic inference in terms of computationally tractable model components: Segmenting a full 3-D volume takes around a minute. Accurate segmentations demonstrate the benefit of using global shape ...

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    22. Optical Coherence Tomography retinal thickness and volume measurements in X-linked Retinoschisis

      Optical Coherence Tomography retinal thickness and volume measurements in X-linked Retinoschisis

      Purpose To analyze retinal thickness and volume measurements of X-linked retinoschisis patients by spectral domain optical coherence tomography (SD-OCT) and correlate these findings with visual acuity and patient age. Design Retrospective comparative case series Methods Sixty-three eyes of 33 male patients with X-linked retinoschisis were gleaned from an Optovue RTVue SD-OCT database at the University of Illinois at Chicago. Forty-one eyes of 21 patients with low refractive error, no visual impairment, and no known retinal disease served as age-similar controls. The mean age of the retinoschisis patients was 26.4 years. The mean age of patient controls was 30.0 ...

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    23. A Longitudinal Comparison of Spectral-Domain Optical Coherence Tomography and Fundus Autofluorescence in Geographic Atrophy

      A Longitudinal Comparison of Spectral-Domain Optical Coherence Tomography and Fundus Autofluorescence in Geographic Atrophy

      Purpose To identify reliable criteria based on spectral-domain optical coherence tomography (SD-OCT) to monitor disease progression in geographic atrophy due to age-related macular degeneration (AMD) compared with lesion size determination based on fundus autofluorescence (FAF). Design Prospective longitudinal observational study Methods Setting :Institutional. Study population A total of 48 eyes in 24 patients with geographic atrophy. Observation Procedures Eyes with geographic atrophy were included and examined at baseline and months 3, 6, 9 and 12. At each study visit best-corrected visual acuity (BCVA), FAF and SD-OCT imaging using a Spectralis HRA + OCT System were performed. FAF images were analyzed using ...

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