1. Articles in category: Ophthalmology

    577-600 of 9568 « 1 2 ... 22 23 24 25 26 27 28 ... 397 398 399 »
    1. Optical Coherence Tomography Angiography in Macular Edema (Book Chapter)

      Optical Coherence Tomography Angiography in Macular Edema (Book Chapter)

      OCT angiography is a promising new method to visualize the retinal vasculature and choroidal vascular layers in the macular area and provides depth resolved functional information of the blood flow in the vessels. Given that the main moving elements in the eye fundus are contained in vessels, determining a vascular decorrelation signal enables visualization of 3-dimensional retinal and choroidal vascular network without the administration of intravenous dye and thus reducing the risk of potential adverse events.

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    2. Choroidal Thickness Variation According to Refractive Error Measured by Spectral Domain-optical Coherence Tomography in Korean Children

      Choroidal Thickness Variation According to Refractive Error Measured by Spectral Domain-optical Coherence Tomography in Korean Children

      Purpose To assess choroidal thickness (CT) variation according to refractive errors using enhanced-depth imaging optical coherence tomography. Methods Eighty-nine eyes (in 89 children) <±6 diopter were categorized into three groups: hyperopia, emmetropia, and myopia, according to refractive error, and underwent choroidal scans using enhanced-depth imaging-optical coherence tomography. CT was measured at the fovea and at 1 mm and 3 mm nasal (N1 and N3), temporal (T1 and T3), superior (S1 and S3), and inferior (I1 and I3) from the fovea. Results Mean foveal CTs were 346.86 µm, 301.97 µm, and 267.46 µm in the hyperopia, emmetropia, and ...

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    3. Interchangeability and reliability of macular perfusion parameter measurements using optical coherence tomography angiography

      Interchangeability and reliability of macular perfusion parameter measurements using optical coherence tomography angiography

      Aim The aim of the study was to investigate the interchangeability and reliability of macular perfusion measurements using optical coherence tomography angiography. Methods A prospective cross-sectional observational study. Healthy adult Chinese subjects were recruited. Macular perfusion parameters were automatically analysed by software included in a spectral-domain optical coherence tomography system. The vessel density (VD) of the whole, parafovea, superior-hemi, inferior-hemi, fovea, temporal, superior, nasal and inferior quadrants as well as the foveal avascular zone (FAZ) and choroidal capillary VD (CCVD) were quantified. Results A total of 51 eyes in 27 subjects were included (8 men and 19 women, mean age ...

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    4. West Nile Virus Chorioretinitis With Foveal Involvement Evolution of Lesions on Optical Coherence Tomography

      West Nile Virus Chorioretinitis With Foveal Involvement Evolution of Lesions on Optical Coherence Tomography

      Purpose: To describe the clinical course of foveal West Nile virus (WNV) chorioretinitis with longitudinal spectral domain optical coherence tomography (SD-OCT) imaging. Methods: Case report. Results: A 41-year-old man with diabetes mellitus presented with flashes and floaters of both eyes (OU) and decreased vision of the right eye (OD) 2 weeks after being discharged from a local hospital. He had been treated for WNV meningoencephalitis, and he recovered systemically with supportive therapy. Ophthalmic examination revealed WNV chorioretinitis bilaterally, with predominantly foveal involvement OD. His best-corrected visual acuity (BCVA) was 8/200 OD and 20/20 of the left eye (OS ...

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    5. QUANTIFICATION OF RETINAL VESSEL TORTUOSITY IN DIABETIC RETINOPATHY USING OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY

      QUANTIFICATION OF RETINAL VESSEL TORTUOSITY IN DIABETIC RETINOPATHY USING OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY

      Purpose: To investigate the association of vessel tortuosity with severity of diabetic retinopathy (DR) using optical coherence tomography angiography. Methods: We retrospectively analyzed 30 healthy eyes and 121 eyes of diabetic subjects with no DR, mild nonproliferative DR (NPDR), moderate to severe NPDR and proliferative DR (PDR). Binarized images were used to quantify the vessel tortuosity, vessel density, foveal avascular zone (FAZ) area, and FAZ acircularity. The vessels were divided vertically as superficial retinal layer and deep retinal layer, and horizontally as circular areas with 3 mm and 1.5 mm diameters. Analysis of variance was performed for multiple comparisons ...

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    6. SD-OCT Choroidal Thickness in Advanced Primary Open-Angle Glaucoma

      SD-OCT Choroidal Thickness in Advanced Primary Open-Angle Glaucoma

      Purpose: To assess the choroidal thickness in advanced primary open-angle glaucoma (POAG) comparing patients affected by advanced glaucoma and normal subject using spectral domain optical coherence tomography (SD-OCT). Methods: In total, 35 eyes of 35 patients affected by POAG with advanced perimetric defect (mean deviation worse than -12 dB) were prospectively enrolled and underwent a complete ophthalmologic examination, including enhanced depth imaging SD-OCT. One eye of 35 healthy subjects served as control group. Choroidal thickness was measured at the subfoveal location, at 0.5, 1.0, and 2.0 mm nasal and temporal to the fovea. Primary outcome measure was ...

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    7. Effects of diurnal, lighting, and angle-of-incidence variation on anterior segment optical coherence tomography (AS-OCT) angle metrics

      Effects of diurnal, lighting, and angle-of-incidence variation on anterior segment optical coherence tomography (AS-OCT) angle metrics

      Background First reported study to assess the effect of diurnal variation on anterior chamber angle measurements, as well as, to re-test the effects of lighting and angle-of-incidence variation on anterior chamber angle (ACA) measurements acquired by time-domain anterior segment optical coherence tomography (AS-OCT). Methods A total of 30 eyes from 15 healthy, normal subjects underwent anterior chamber imaging using a Visante time-domain AS-OCT according to an IRB-approved protocol. For each eye, the inferior angle was imaged twice in the morning (8 am – 10 am) and then again in the afternoon (3 pm – 5 pm), under light meter-controlled conditions with ambient ...

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    8. Influence of cataract on image quality and macular thickness measured using spectral domain optical coherence tomography: a prospective cohort study

      Influence of cataract on image quality and macular thickness measured using spectral domain optical coherence tomography: a prospective cohort study

      Background: Optical coherence tomography (OCT) is one of the most useful imaging techniques in the management of retinal diseases affecting the macula. Factors affecting the image quality of OCT may affect the macular thickness and hence treatment of retinal pathologies. This study was aimed to evaluate the influence of cataract on macular scans using spectral domain OCT. Methods: The prospective study was done in 36 patients with cataract. Cataract was graded as cortical, nuclear or posterior cataracts. All patients underwent small incision cataract surgery. Pre and post-operative imaging of the macula (4 weeks after surgery) using spectral domain OCT. The ...

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    9. Role of high resolution optical coherence tomography in diagnosing ocular surface squamous neoplasia with coexisting ocular surface diseases

      Role of high resolution optical coherence tomography in diagnosing ocular surface squamous neoplasia with coexisting ocular surface diseases

      Purpose Coexistence of an ocular surface disease can mask the typical features of ocular surface squamous neoplasia (OSSN). The purpose of this study was to evaluate high resolution optical coherence tomography (HR-OCT) as an adjunct in the detection and differentiation of OSSN within coexisting ocular surface pathologies. Methods Retrospective study of 16 patients with ocular surface disease and lesions suspicious for OSSN that were evaluated with HR-OCT. HR-OCT images of the lesions were taken to look for evidence of OSSN. Biopsies were performed in all cases, and the HR-OCT findings were compared to the histological results. Results Of the 16 ...

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    10. ADULT-ONSET FOVEOMACULAR VITELLIFORM DYSTROPHY EVALUATED BY MEANS OF OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY: A Comparison With Dry Age-Related Macular Degeneration and Healthy Eyes

      ADULT-ONSET FOVEOMACULAR VITELLIFORM DYSTROPHY EVALUATED BY MEANS OF OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY: A Comparison With Dry Age-Related Macular Degeneration and Healthy Eyes

      Purpose: To investigate alterations of superficial and deep retinal vascular densities, as well as of choroidal thickness, in patients affected by adult-onset foveomacular vitelliform dystrophy (AOFVD). Methods: A total of 22 eyes (15 patients) affected by AOFVD were recruited in the study. Furthermore, 20 eyes of 20 healthy subjects and 20 eyes of 18 patients affected by intermediate dry age-related macular degeneration (AMD) were enrolled. All patients underwent a complete ophthalmologic examination, including optical coherence tomography angiography. Outcome measures were superficial vessel density, deep vessel density, and choroidal thickness. Results: Parafoveal superficial vessel density was increased in patients with AOFVD ...

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    11. Relationship of Optic Nerve Structure and Function to Peripapillary Vessel Density Measurements of Optical Coherence Tomography Angiography in Glaucoma

      Relationship of Optic Nerve Structure and Function to Peripapillary Vessel Density Measurements of Optical Coherence Tomography Angiography in Glaucoma

      Purpose: To evaluate the sectoral and global structure-structure (vessel density-retinal nerve fiber layer thickness) and structure-function (vessel density-visual sensitivity loss) relationships of peripapillary vessel density measurements on optical coherence tomography angiography in primary open-angle glaucoma and to determine if fractional polynomial (FP) models characterize the relationships better than linear models. Materials and Methods: In a cross-sectional study, structure-structure and structure-function relationships of peripapillary vessel densities were determined in 227 eyes of 143 subjects (63 control and 164 primary open-angle glaucoma eyes) who had undergone standard automated perimetry and optical coherence tomography testing within 6 months of each other, using linear ...

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    12. Multimodal imaging of suspicious choroidal neoplasms in a primary eye-care clinic

      Multimodal imaging of suspicious choroidal neoplasms in a primary eye-care clinic

      Small suspicious choroidal neoplasms commonly present a diagnostic challenge in primary eye-care clinics, where they are most likely to present. Differentiating benign from malignant choroidal neoplasms is essential for facilitating early diagnosis and treatment, potentially decreasing the risk of metastasis and vision loss in some cases. The purpose of this review is to describe the clinical, spectral-domain optical coherence tomography and fundus autofluorescence features of suspicious choroidal neoplasms in a case series of patients presenting to a primary eye-care clinic at the Veterans Health Administration, Cleveland, Ohio, USA.

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    13. Combined spectral-domain optical coherence tomography and hyperspectral imaging applied for tissue analysis: preliminary results

      Combined spectral-domain optical coherence tomography and hyperspectral imaging applied for tissue analysis: preliminary results

      In recent years many optoelectronic techniques have been developed for improvement and the development of devices for tissue analysis. Spectral-Domain Optical Coherence Tomography (SD-OCT) is a new medical interferometric imaging modality that provides depth resolved tissue structure information with resolution in the μm range. However, SD-OCT has its own limitations and cannot offer the biochemical information of the tissue. These data can be obtained with hyperspectral imaging, a non-invasive, sensitive and real time technique. In the present study we have combined Spectral-Domain Optical Coherence Tomography (SD-OCT) with Hyperspectral imaging (HSI) for tissue analysis. The Spectral-Domain Optical Coherence Tomography (SD-OCT) and ...

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    14. A Case Report of Occipital Lobe Epilepsy and Related Optical Coherence Tomography Findings

      A Case Report of Occipital Lobe Epilepsy and Related Optical Coherence Tomography Findings

      Purpose In the present case report, visual pathway damage confirmed by retinal ganglion cell layer (GCL) damage on optical coherence tomography (OCT) in occipital lobe epilepsy was described. Case summary A 25-year-old female with idiopathic generalized epilepsy developed visual blurring followed by a generalized seizure. On brain magnetic resonance imaging (MRI), very subtle changes of the cortex in the left parietooccipital lobe were observed. Two days after the attack, even after the disappearance of epileptiform wave on electroencephalogram (EEG), visual acuity in both eyes was 0.5 and a perimetry revealed nearly complete visual defect in both eyes. OCT showed ...

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    15. Comparison of Central Corneal Thickness Measured by Swept-source Optical Coherence Tomography and Ultrasound Pachymetry

      Comparison of Central Corneal Thickness Measured by Swept-source Optical Coherence Tomography and Ultrasound Pachymetry

      Purpose To analyze and compare ultrasound pachymetry (USP) with a more recently adopted device, the intra ocular lens (IOL) master 700, which are both used to measure central corneal thickness. Methods The central corneal thickness was measured in 24 eyes of 12 glaucoma patients and in 83 eyes of 42 normal patients. First, the IOL master 700 was used to measure the central corneal thickness, followed by measurements taken using USP later. The results were analyzed using a paired t -test. We analyzed the agreement and the correlations between the two test devices by using Bland-Altman plots and the Pearson ...

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    16. Ultra-Wide-Field Fundus Autofluorescence and Spectral-Domain Optical Coherence Tomography Findings in Syphilitic Outer Retinitis

      Ultra-Wide-Field Fundus Autofluorescence and Spectral-Domain Optical Coherence Tomography Findings in Syphilitic Outer Retinitis

      BACKGROUND AND OBJECTIVE: To determine the ultra-wide-field fundus autofluorescence (UWFFAF) and optical coherence tomography (OCT) features of syphilitic outer retinopathy (SOR). PATIENTS AND METHODS: Retrospective chart review. RESULTS: Three patients with SOR were investigated. Treatment with parenteral penicillin led to improvement of outer retinopathy, visual acuity, and symptoms. UWFFAF showed speckled hyperautofluorescence, hypoautofluorescence, and normal autofluorescence, similar to what has been described as a trizonal pattern in acute zonal occult outer retinopathy (AZOOR) in the chronic case of SOR, but with hyperautofluorescent areas in the two acute cases. OCT showed disruption of the photoreceptor outer segment ellipsoid zone and external ...

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    17. Reflectometry and Optical Coherence Tomography for Non-invasive High Resolution Tear Film Thickness Evaluation and Ophthalmic Imaging (Thesis)

      Reflectometry and Optical Coherence Tomography for Non-invasive High Resolution Tear Film Thickness Evaluation and Ophthalmic Imaging (Thesis)

      Dry eye debilitates the patients physically, limit their ability to perform daily tasks, cause clinical depression, and compromise quality of life. Accurate diagnosis of the dry eye and the research on the pathological mechanism and treatment both depend largely on the available measurement techniques. The development of new measurement techniques helps better understanding of the disease and paves the way for accurate early diagnosis and better treatment. The purpose of this study was to develop additional tools in ophthalmic study for non-invasive high resolution tear film thickness evaluation and eye imaging. Optical coherence tomography (OCT) is a non-invasive imaging technology ...

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    18. Alterations of the Foveal Avascular Zone Measured by Optical Coherence Tomography Angiography in Glaucoma Patients With Central Visual Field Defects

      Alterations of the Foveal Avascular Zone Measured by Optical Coherence Tomography Angiography in Glaucoma Patients With Central Visual Field Defects

      Purpose : To investigate whether the area and shape of the foveal avascular zone (FAZ) as assessed by optical coherence tomography angiography (OCTA) are altered in glaucomatous eyes with central visual field defects (CVFDs). Methods : A total of 78 patients with open-angle glaucoma with central or peripheral visual field defects (PVFDs) confined to a single hemifield were studied retrospectively. Foveal avascular zone area and circularity were measured using OCTA images from the superficial retinal layer. Central retinal visual field (VF) sensitivity using Swedish Interactive Threshold Algorithm 24-2 VF and macular ganglion cell–inner plexiform layer (mGCIPL) thickness were measured. The FAZ ...

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    19. Optical coherence tomography angiography artifacts in retinal pigment epithelial detachment

      Optical coherence tomography angiography artifacts in retinal pigment epithelial detachment

      Objective To describe optical coherence tomography angiography (OCTA) reflectance artifacts secondary to retinal pigment epithelial detachment (RPED). Design Retrospective review. Methods Four eyes from 4 subjects were included. Three presented with RPED and 1 eye was a normal control. Two eyes diagnosed with RPED and the normal eye were evaluated using en face OCTA centred at the fovea acquired using the RTVue XR Avanti (Optovue Inc). In the third eye with RPED, OCTA imaging was performed using a CIRRUS 5000 prototype modified to do OCTA imaging on a spectral domain OCT platform provided by Carl Zeiss Meditec, Inc. The segmented ...

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    20. Distinguishing between contact lens warpage and ectasia: Usefulness of optical coherence tomography epithelial thickness mapping

      Distinguishing between contact lens warpage and ectasia: Usefulness of optical coherence tomography epithelial thickness mapping

      Purpose To distinguish between corneal ectasia and contact lens–related warpage by characteristic patterns on corneal topography and optical coherence tomography (OCT) epithelial thickness maps. Setting Casey Eye Institute, Portland, Oregon, USA. Design Prospective and retrospective case series. Methods Axial and mean power maps were obtained on corneal topography systems. Epithelial thickness maps were generated using RTVue OCT. A sector divider was applied to all maps. The locations of the minimum epithelial thickness, maximum epithelial thickness, maximum axial power, and maximum mean power were determined based on sector averages. Agreement was defined as the extremums occurring in the same or ...

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    21. Optical Coherence Tomography Angiography in Nonarteritic Anterior Ischemic Optic Neuropathy

      Optical Coherence Tomography Angiography in Nonarteritic Anterior Ischemic Optic Neuropathy

      Background: Optical coherence tomography angiography (OCTA) has demonstrated good utility in qualitative analysis of retinal and choroidal vasculature and therefore may be relevant in the diagnostic and treatment efforts surrounding nonarteritic anterior ischemic optic neuropathy (NAION). Methods: Retrospective, cross-sectional study of 10 eyes of 9 patients with a previous or new diagnosis of NAION that received imaging with OCTA between November 2015 and February 2016. Two independent readers qualitatively analyzed the retinal peripapillary capillaries (RPC) and peripapillary choriocapillaris (PCC) for flow impairment. Findings were compared with automated visual field and structural optical coherence tomography (OCT) studies. Results: Flow impairment seen ...

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    22. Columbia University Receives NIH Grant for Studying Models and Mechanisms of Optic Nerve Diseases

      Columbia University Receives NIH Grant  for Studying Models and Mechanisms of Optic Nerve Diseases

      Columbia University Receives at 2017 NIH Grant for $460,107 for Studying Models and Mechanisms of Optic Nerve Diseases. The principal investigato ris Donald Hood. The program began in 1977 and ends in 2019. Below is a summary of the proposed work. Glaucoma is the second leading cause of blindness in the world, but, with proper treatment, blindness can be avoided in the overwhelming majority of individuals. Our long-term goal is to improve the detection of early glaucomatous damage, as well as the detection of progression of such damage. We focus in large part on damage to the macula, the ...

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    23. Optical Coherence Tomography and Cerebral Spinal Fluid Pressure

      Optical Coherence Tomography and Cerebral Spinal Fluid Pressure

      Glaucoma is defined as an optic neuropathy, primarily induced by an intraocular pressure (IOP) that is higher than the optic nerve can tolerate. But what determines the pressure the optic nerve can tolerate? Seemingly, the answer is that the pressure a given optic nerve can tolerate is related to the eye’s biomechanics, local optic nerve anatomy, optic nerve perfusion, and finally the cerebral spinal fluid (CSF) pressure. The CSF pressure serves as the back pressure on the optic disc, and a growing body of evidence shows that eyes with a lower CSF pressure are more susceptible to glaucoma. One ...

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