1. Articles in category: Ophthalmology

    553-576 of 7816 « 1 2 ... 21 22 23 24 25 26 27 ... 324 325 326 »
    1. Advanced image processing for optical coherence tomographic angiography of macular diseases

      Advanced image processing for optical coherence tomographic angiography of macular diseases

      This article provides an overview of advanced image processing for three dimensional (3D) optical coherence tomographic (OCT) angiography of macular diseases, including age-related macular degeneration (AMD) and diabetic retinopathy (DR). A fast automated retinal layers segmentation algorithm using directional graph search was introduced to separates 3D flow data into different layers in the presence of pathologies. Intelligent manual correction methods are also systematically addressed which can be done rapidly on a single frame and then automatically propagated to full 3D volume with accuracy better than 1 pixel. Methods to visualize and analyze the abnormalities including retinal and choroidal neovascularization, retinal ...

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    2. Macular Thickness Assessed with Optical Coherence Tomography in Young Chinese Myopic Patients

      Macular Thickness Assessed with Optical Coherence Tomography in Young Chinese Myopic Patients

      Purpose. To evaluate the variations in macular thickness in young Chinese myopic persons and the association with axial length (AL), spherical equivalence refraction (SE), age, intraocular pressure, and sex. Methods. In total, 133 young Chinese myopic subjects between 18 and 30 years of age were selected. The macular thickness was assessed using third-generation optical coherence tomography. AL, intraocular pressure, and SE were also measured. Results. The mean central foveal thickness was   µ m. The macula was consistently thinner in women than in men. Central foveal thickness had a significant positive correlation with AL and a negative correlation with SE. In the ...

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    3. Retinal vessel diameter changes in different severities of diabetic retinopathy by SD-OCT

      Retinal vessel diameter changes in different severities of diabetic retinopathy by SD-OCT

      To evaluate retinal vessel diameters in relation to different severity grades of diabetic retinopathy (DR) using spectral-domain optical coherence tomography (SD-OCT). Patients with varying degrees of nonproliferative DR (NPDR) underwent circular OCT scans centered on the optic nerve head using a SD-OCT. These cases were retrospectively reviewed. The presence and severity of DR was assessed using Early Treatment Diabetic Retinopathy Study protocols. The 5 largest retinal arterioles and venules were labeled and measured on OCT scans for each patient according to previously published methods. Vertical vessel inner contour diameter, vertical vessel outer contour diameter, and reflectance shadowing width were among ...

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    4. Spectral-domain optical coherence tomography findings of tractional retinal elevation in patients with diabetic retinopathy

      Spectral-domain optical coherence tomography findings of tractional retinal elevation in patients with diabetic retinopathy

      Purpose To evaluate the clinical and morphological characteristics as well as the surgical outcomes of tractional retinal elevation (TRE) in patients with proliferative diabetic retinopathy (PDR) by analyzing spectral-domain optical coherence tomography (SD-OCT). Methods SD-OCT images of 26 eyes (24 patients) who visited our clinic because of TRE and PDR from August 2011 to August 2014 were reviewed. According to the presence or absence of tractional retinal detachment (TRD), patients were classified into group 1 (without TRD) or group 2 (with TRD), and the clinical characteristics and surgical outcomes of the two groups were compared. Furthermore, we categorized the SD-OCT ...

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    5. Influence of epiretinal membrane on the measurement of peripapillary retinal nerve fibre layer thickness using spectral-domain coherence tomography

      Influence of epiretinal membrane on the measurement of peripapillary retinal nerve fibre layer thickness using spectral-domain coherence tomography

      Background/aims To investigate the effect of epiretinal membrane (ERM) on peripapillary retinal nerve fibre layer (RNFL) thickness measurements using spectral-domain optical coherence tomography (Spectralis; Heidelberg Engineering). Methods A total of 134 patients with idiopathic ERM and 63 healthy controls were included in this observational comparative study. We categorised ERMs into three severity grades, based on retinal appearance in macular scans. All eyes with ERM were classified into two groups; those involving the peripapillary scan area (ERM+pp, n=68 eyes) and not involving the peripapillary scan area (ERM−pp, n=66 eyes) using the macular disc scan. Peripapillary RNFL ...

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    6. En face enhanced depth imaging optical coherence tomography of polypoidal choroidal vasculopathy

      En face enhanced depth imaging optical coherence tomography of polypoidal choroidal vasculopathy

      Purpose To analyse retinal and choroidal changes associated with polypoidal choroidal vasculopathy (PCV) using en face spectral-domain optical coherence tomography (SD-OCT). Methods In this retrospective and descriptive study, we collected imaging of patients affected with PCV examined using enhanced depth imaging (EDI) SD-OCT, fluorescein and indocyanine green angiography for a qualitative analysis. The three-dimensional reconstruction of 197 transverse sections with EDI SD-OCT at 30 μm intervals provided a virtual macular brick through which 496 sections in the coronal plane resulted in a C-scan or en face OCT image. Results 30 eyes of 30 patients affected with PCV were studied. En ...

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    7. Automated estimation of choroidal thickness distribution and volume based on OCT images of posterior visual section

      Automated estimation of choroidal thickness distribution and volume based on OCT images of posterior visual section

      A variety of vision ailments are indicated by anomalies in the choroid layer of the posterior visual section. Consequently, choroidal thickness and volume measurements, usually performed by experts based on optical coherence tomography (OCT) images, have assumed diagnostic significance. Now, to save precious expert time, it has become imperative to develop automated methods. To this end, one requires choroid outer boundary (COB) detection as a crucial step, where difficulty arises as the COB divides the choroidal granularity and the scleral uniformity only notionally, without marked brightness variation. In this backdrop, we measure the structural dissimilarity between choroid and sclera by ...

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    8. Diagnostic Accuracy of the Spectralis and Cirrus Reference Databases in Differentiating between Healthy and Early Glaucoma Eyes

      Diagnostic Accuracy of the Spectralis and Cirrus Reference Databases in Differentiating between Healthy and Early Glaucoma Eyes

      Purpose To evaluate and compare the diagnostic accuracy of global and sector analyses for detection of early visual field (VF) damage using the retinal nerve fiber layer (RNFL) reference databases of the Spectralis (Heidelberg Engineering, Heidelberg, Germany) and Cirrus (Carl Zeiss Meditec, Dublin, CA) spectral-domain optical coherence tomography (SD OCT) devices. Methods Healthy subjects and glaucoma suspects from the Diagnostic Innovations in Glaucoma Study (DIGS) and African Descent and Glaucoma Evaluation Study (ADAGES) with at least 2 years of follow-up were included. Global and sectoral RNFL measures were classified as within normal limits, borderline (BL), and outside normal limits (ONL ...

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    9. ATTENUATION OF THE GANGLION CELL LAYER IN A PREMATURE INFANT REVEALED WITH HANDHELD SPECTRAL DOMAIN OCT

      ATTENUATION OF THE GANGLION CELL LAYER IN A PREMATURE INFANT REVEALED WITH HANDHELD SPECTRAL DOMAIN OCT

      Purpose: To report on subclinical retinal abnormalities shown through handheld spectral domain optical coherence tomography on a premature infant. Methods: Case report. Results: The initial and follow-up exams on a premature infant revealed severely attenuated ganglion cell and nerve fiber layers. There was cystoid macular edema in both eyes at the initial visits, which resolved by the 1-year follow-up. Discussion: Optical coherence tomography can reveal significant retinal abnormalities in premature infants which are not detectable through funduscopic exam. Documenting such findings may be useful for the comprehensive management of vision problems in children with a history of premature birth. This ...

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      Mentions: Joseph Carroll
    10. Combined depth imaging of choroid in uveitis

      Combined depth imaging of choroid in uveitis

      Background Understanding the changes that occur in the choroid is of paramount importance in various uveitis entities. B-scan ultrasonography and indocyanine green angiography can be used to study choroid. Currently, spectral-domain optical coherence tomography is used as the standard noninvasive technique to study the choroid by enhanced depth imaging. Our aim was to study the structural visibility of the choroid using spectral-domain optical coherence tomography in the same area of interest in patients with uveitis with posterior segment manifestations using conventional, enhanced depth imaging (EDI), and combined depth imaging (CDI) techniques. Results Fifty-eight (58) eyes of 48 patients between age ...

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      Mentions: Rohit Shetty
    11. Inter-device size variation of small choroidal nevi measured using stereographic projection ultra-widefield imaging and optical coherence tomography

      Inter-device size variation of small choroidal nevi measured using stereographic projection ultra-widefield imaging and optical coherence tomography

      Purpose Our purpose was to compare the tumor sizes of small choroidal nevi using ultra-widefield imaging (UWF) and different optical coherence tomography systems. Methods Thirteen choroidal nevi were measured using automatic and manual segmentation techniques, including enhanced depth imaging spectral-domain optical coherence tomography (EDI-SDOCT) and 1050 nm swept source OCT (SSOCT), to compare to measurements obtained using the Optos projection ultra-widefield fundus (UWF) imaging technique. Segmentation artifacts were evaluated for all 13 cases, alongside an additional 12 choroidal nevi, using SSOCT. Results In tumor eyes, segmentation artifacts for the choroid-sclera interface were found in 42 % of SSOCT scans. EDI-SDOCT can ...

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      Mentions: Optos
    12. Macular edema with serous retinal detachment post-phacoemulsification followed by spectral domain optical coherence tomography: a report of two cases

      Macular edema with serous retinal detachment post-phacoemulsification followed by spectral domain optical coherence tomography: a report of two cases

      Background Macular edema and detachment at the first day after an uneventful cataract surgery is very rare, and has been reported previously with the use of high concentrations of intra-cameral cefuroxime. However, we hereby reported two cases of macular edema with extensive serous retinal detachment the first day after an uneventful phacoemulsification with intra-cameral injection of a standard dose of cefuroxime during the procedure. Case presentation A 68-year-old female and a 63-year-old male without any special history both underwent an uneventful phacoemulsification surgery and 1 mg/0.1 ml of cefuroxime solution was injected into the anterior chamber at the ...

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    13. Distortion Correction of Visante Optical Coherence Tomography Cornea Images

      Distortion Correction of Visante Optical Coherence Tomography Cornea Images

      Purpose: Quantitative biometry measurements from uncorrected anterior segment optical coherence tomography (AS-OCT) images are inaccurate because of spatial and optical distortions. Prior reported distortion correction equations for the Visante AS-OCT were not reproducible. The goal was to calculate the distortions and provide equations to correct corneal parameters for the Visante AS-OCT to get a central corneal radius of curvature from young and older subjects. Methods: Five contact lenses (CLs) of known front and back radii of curvature and central thickness were imaged using the Visante AS-OCT (Carl Zeiss, Dublin, CA). Contact lens surface coordinates from Visante images were identified and ...

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    14. Five streams of education at the National OCT Conference

      Five streams of education at the National OCT Conference

      The first ever conference to focus completely on Optical Coherence Tomography will offer five different streams in Birmingham next month over the two day event. The diverse programme will see Professor Paulo Stanga hold an opening keynote on both days and present on the ‘Evolution of OCT’ on the first day and ‘The Macula – Beyond my Referral’ which will review current and emerging treatment options for macular conditions; Professor Heinrich Heimann will present on ‘OCT Findings in the Differential Diagnosis and Treatment of Retinal and Choroidal Tumours’; Professor Magdy Moussa is to present on ‘OCT in High Myopia’ and Dr ...

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    15. Choroidal line scan measurements in swept-source optical coherence tomography as surrogates for volumetric thickness assessment - American Journal of Ophthalmology

      Choroidal line scan measurements in swept-source optical coherence tomography as surrogates for volumetric thickness assessment - American Journal of Ophthalmology

      Purpose To compare choroidal thickness of different areas on swept-source optical coherence tomography (SS-OCT) line and cube scans for their interchangeable use. Design Validity analysis. Methods SS-OCT line and cube scans were obtained from 21 patients with various choroidal thicknesses. Subfoveal centerpoint choroidal thickness, mean central millimeter choroidal thickness and mean 6-mm area choroidal thicknesses were obtained from both eyes by two independent graders in a reading center setting. Cross-correlations were performed using Passing and Bablok regression models. A 95% confidence interval of slope that included 1 was considered to indicate no significant difference. Average choroidal thickness of centerpoint, early ...

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    16. Diagnostic Optical Imaging Technology and Its Principles (Book Chapter)

      Diagnostic Optical Imaging Technology and Its Principles (Book Chapter)

      Analysis of tissue structures is important for investigating pathological changes and diagnosing neural diseases. Recent advances in ophthalmology regarding the diagnosis of neurosensory retinal diseases have introduced optical coherence tomography (OCT) as a near-infrared imaging modality to provide noninvasive and real-time imaging and sensing with ultrahigh resolution for imaging subsurface cross sections of the human retina. This chapter gives a brief overview and the basic principles of this emerging optical imaging modality.

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      Mentions: Korea University
    17. Long time remodeling during retinal degeneration evaluated by Optical Coherence Tomography, immunocytochemistry and Fundus Autofluorescence

      Long time remodeling during retinal degeneration evaluated by Optical Coherence Tomography, immunocytochemistry and Fundus Autofluorescence

      Purpose To characterize the relationship between fundus autofluorescence (FAF), Optical Coherence Tomography (OCT) and immunohistochemistry over the course of chronic retinal degeneration in the P23H rat. Methods Homozygous albino P23H rats, Sprague-Dawley (SD) rats and pigmented Long Evans (LE) rats were used. A Spectralis HRA OCT system was used for scanning laser ophthalmoscopy (SLO) imaging OCT and angiography. To determine FAF, fluorescence was excited using diode laser at 488 nm. A fast retina map OCT was performed using the optic nerve as a landmark. Immunohistochemistry (IHC) was performed to correlate with the findings of OCT and FAF changes. Results During ...

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    18. Portable optical coherence tomography (OCT) systems

      Portable optical coherence tomography (OCT) systems

      Portable optical coherence tomography (OCT) devices including at least one mirror configured to scan at least two directions are provided. The portable OCT devices are configured to provide a portable interface to a sample that can be aligned to the sample without repositioning the sample. Related systems are also provided.

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    19. Anterior segment imaging in glaucoma: An updated review

      Anterior segment imaging in glaucoma: An updated review

      Anterior segment imaging allows for an objective method of visualizing the anterior segment angle. Two of the most commonly used devices for anterior segment imaging include the anterior segment optical coherence tomography (AS-OCT) and the ultrasound biomicroscopy (UBM). AS-OCT technology has several types, including time-domain, swept-source, and spectral-domain-based configurations. We performed a literature search on PubMed for articles containing the text "anterior segment OCT," "ultrasound biomicroscopy," and "anterior segment imaging" since 2004, with some pertinent references before 2004 included for completeness. This review compares the advantages and disadvantages of AS-OCT and UBM, and summarizes the most recent literature regarding the ...

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      Mentions: Yale University
    20. Diagnostic accuracy of posterior pole asymmetry analysis parameters of spectralis optical coherence tomography in detecting early unilateral glaucoma

      Diagnostic accuracy of posterior pole asymmetry analysis parameters of spectralis optical coherence tomography in detecting early unilateral glaucoma

      Purpose: To report the diagnostic ability of posterior pole asymmetry analysis (PPAA) parameters of spectralis optical coherence tomography (OCT) in detecting early unilateral glaucoma. Methods: A prospective, cross-sectional study which included 80 eyes of 80 normal subjects and 76 eyes of 76 patients with unilateral early primary open-angle glaucoma by Hodapp-Anderson-Parrish classification. All subjects were of age more than 18 years, best-corrected visual acuity 20/40 or better, and a refractive error within ± 5 diopter (D) sphere and ± 3 D cylinder. Control subjects had a normal ocular examination, intraocular pressure (IOP) <22 mmHg, no past history of high IOP, no ...

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    21. Real-Time Microscope-Integrated OCT to Improve Visualization in DSAEK for Advanced Bullous Keratopathy

      Real-Time Microscope-Integrated OCT to Improve Visualization in DSAEK for Advanced Bullous Keratopathy

      Purpose: To report the intraoperative use of microscope-integrated optical coherence tomography (MIOCT) to enable visualization for Descemet's stripping automated endothelial keratoplasty (DSAEK) in 2 patients with advanced bullous keratopathy. Methods: Patient 1 was an 83-year-old female and patient 2 was a 28-year-old male both with limited vision and significant pain from bullous keratopathy who underwent palliative DSAEK. Because of the severity and chronicity of the corneal decompensation in both patients, the view past the anterior cornea was negligible using standard microscope illumination techniques. We used spectral-domain (Patient 1) and swept-source (Patient 2) MIOCT, both of which rely on infrared ...

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    22. SINGLE ACQUISITION OF THE VITREOUS, RETINA AND CHOROID WITH SWEPT-SOURCE OPTICAL COHERENCE TOMOGRAPHY IN ACUTE TOXOPLASMOSIS

      SINGLE ACQUISITION OF THE VITREOUS, RETINA AND CHOROID WITH SWEPT-SOURCE OPTICAL COHERENCE TOMOGRAPHY IN ACUTE TOXOPLASMOSIS

      Background/Purpose: To report the swept-source optical coherence tomography (SS-OCT) findings in a case of acute toxoplasmosis chorioretinitis. Methods: A 35-year-old male presented with acute blurry vision and floaters in his left eye. Ophthalmic examination, color photographs, spectral-domain OCT (SD-OCT), enhanced depth imaging OCT (EDI-OCT), SS-OCT and wide-field fluorescein angiography images were obtained to diagnose and follow the subsequent changes of toxoplasmosis chorioretinitis over a 2-month period. Results: Initial imaging with different modalities of SD- and EDI-OCT including radial vitreous scans and horizontal high-speed B-scan raster lines demonstrated thickening of the posterior hyaloid and acute vitreous cells emanating from the ...

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    23. Optical Coherence Tomography Angiography Of Type 3 Neovascularization Secondary To AGE-RELATED Macular Degeneration

      Optical Coherence Tomography Angiography Of Type 3 Neovascularization Secondary To AGE-RELATED Macular Degeneration

      Purpose: To characterize the vascular structure of Type 3 neovascularization secondary to age-related macular degeneration using optical coherence tomography angiography. Methods: Optical coherence tomography angiography cube scans (3 mm × 3 mm) were acquired in 29 eyes of 24 patients with Type 3 lesions secondary to age-related macular degeneration using the RTVue XR Avanti with AngioVue, Split-spectrum amplitude-decorrelation, and motion correction technology. Automated layer segmentation boundaries were adjusted to best visualize the neovascular complex on en face projection images. Results: A distinct neovascular complex could be identified in 10 (34%) eyes, all of which were active on optical coherence tomography imaging ...

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