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Retinal image analysis

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https://www.readbyqxmd.com/read/28640816/topographic-independent-component-analysis-reveals-random-scrambling-of-orientation-in-visual-space
#1
Marina Martinez-Garcia, Luis M Martinez, Jesús Malo
Neurons at primary visual cortex (V1) in humans and other species are edge filters organized in orientation maps. In these maps, neurons with similar orientation preference are clustered together in iso-orientation domains. These maps have two fundamental properties: (1) retinotopy, i.e. correspondence between displacements at the image space and displacements at the cortical surface, and (2) a trade-off between good coverage of the visual field with all orientations and continuity of iso-orientation domains in the cortical space...
2017: PloS One
https://www.readbyqxmd.com/read/28636408/pattern-visual-evoked-potential-pattern-electroretinogram-and-retinal-nerve-fiber-layer-thickness-in-patients-with-migraine-during-and-after-aura
#2
Amany Abd El-Fattah El-Shazly, Yousra Ahmed Farweez, Momen Mahmoud Hamdi, Noha Ezzat El-Sherbiny
PURPOSE: To study pattern visual evoked potential (PVEP), pattern electroretinogram (PERG), and retinal nerve fiber layer (RNFL) thickness in patients with migraine during and after aura. MATERIALS AND METHODS: We included 60 eyes of 60 patients with migraine (Group 1) and 30 healthy volunteers (30 eyes) as controls (Group 2). Group 1 was studied twice, during a visual aura (1-a) and in between attacks (1-b). All participants underwent full ophthalmological examination, PVEP, PERG, and optical coherence tomographyOCT imaging of the RNFL thickness for each patient...
June 21, 2017: Current Eye Research
https://www.readbyqxmd.com/read/28635102/ratiometric-analysis-of-optical-coherence-tomography-measured-in%C3%A2-vivo-retinal-layer-thicknesses-for-the-detection-of-early-diabetic-retinopathy
#3
Basanta Bhaduri, Ryan L Shelton, Ryan M Nolan, Lucas Hendren, Alexandra Almasov, Leanne T Labriola, Stephen A Boppart
Influence of diabetes mellitus (DM) and diabetic retinopathy (DR) on parafoveal retinal thicknesses and their ratios was evaluated. Six retinal layer boundaries were segmented from spectral-domain optical coherence tomography images using open-source software. Five study groups: (1) healthy control (HC) subjects, and subjects with (2) controlled DM, (3) uncontrolled DM, (4) controlled DR and (5) uncontrolled DR, were identified. The one-way analyses of variance (ANOVA) between adjacent study groups (i. e...
June 21, 2017: Journal of Biophotonics
https://www.readbyqxmd.com/read/28634154/improving-consensus-scoring-of-crowdsourced-data-using-the-rasch-model-development-and-refinement-of-a-diagnostic-instrument
#4
Christopher John Brady, Lucy Iluka Mudie, Xueyang Wang, Eliseo Guallar, David Steven Friedman
BACKGROUND: Diabetic retinopathy (DR) is a leading cause of vision loss in working age individuals worldwide. While screening is effective and cost effective, it remains underutilized, and novel methods are needed to increase detection of DR. This clinical validation study compared diagnostic gradings of retinal fundus photographs provided by volunteers on the Amazon Mechanical Turk (AMT) crowdsourcing marketplace with expert-provided gold-standard grading and explored whether determination of the consensus of crowdsourced classifications could be improved beyond a simple majority vote (MV) using regression methods...
June 20, 2017: Journal of Medical Internet Research
https://www.readbyqxmd.com/read/28632734/choroidal-thickness-in-patients-with-coronary-artery-disease
#5
Meleha Ahmad, Patrick A Kaszubski, Lucy Cobbs, Harmony Reynolds, Roland Theodore Smith
PURPOSE: To evaluate choroidal thickness (CTh) in patients with coronary artery disease (CAD) compared to healthy controls. DESIGN: Cross-sectional. METHODS: Setting: Ambulatory clinic of a large city hospital. Patient population: Thirty-four patients had documented CAD, defined as history of >50% obstruction in at least one coronary artery on cardiac catheterization, positive stress test, ST elevation myocardial infarction, or revascularization procedure...
2017: PloS One
https://www.readbyqxmd.com/read/28624323/post-receptor-neuronal-loss-in-intermediate-age-related-macular-degeneration
#6
Enrico Borrelli, Nizar Saleh Abdelfattah, Akihito Uji, Muneeswar Gupta Nittala, David S Boyer, SriniVas R Sadda
PURPOSE: To investigate the relationship between ganglion cell complex (GCC) thickness and photoreceptor alterations in eyes with intermediate age-related macular degeneration (AMD). DESIGN: Retrospective case-control study. METHODS: We collected data from 68 eyes with intermediate AMD from 68 patients with spectral domain optical coherence tomography (SD-OCT) imaging. A control group of 50 eyes from 50 healthy subjects was included for comparison...
June 14, 2017: American Journal of Ophthalmology
https://www.readbyqxmd.com/read/28623545/analysis-of-genotypes-and-phenotypes-in-chinese-children-with-tuberous-sclerosis-complex
#7
Dayong Bai, Junyang Zhao, Li Li, Jun Gao, Xu Wang
Tuberous sclerosis complex (TSC) is a neurocutaneous syndrome with serious clinical presentations, an autosomal dominant genetic disorder involving multiple organs and systems. We retrospectively investigated the clinical manifestations and genotypes of 20 Chinese children with TSC to enable informed diagnostic and surveillance recommendations in China. A retrospective analysis of clinical manifestations in 20 children (7.00±5.30 years old) with TSC was conducted. A genetic testing of the genes TSC1 and TSC2 was performed in 14 children...
June 14, 2017: Science China. Life Sciences
https://www.readbyqxmd.com/read/28623452/enhanced-visualization-of-the-retinal-vasculature-using-depth-information-in-oct
#8
Joaquim de Moura, Jorge Novo, Pablo Charlón, Noelia Barreira, Marcos Ortega
Retinal vessel tree extraction is a crucial step for analyzing the microcirculation, a frequently needed process in the study of relevant diseases. To date, this has normally been done by using 2D image capture paradigms, offering a restricted visualization of the real layout of the retinal vasculature. In this work, we propose a new approach that automatically segments and reconstructs the 3D retinal vessel tree by combining near-infrared reflectance retinography information with Optical Coherence Tomography (OCT) sections...
June 17, 2017: Medical & Biological Engineering & Computing
https://www.readbyqxmd.com/read/28622398/axial-length-variation-impacts-on-superficial-retinal-vessel-density-and-foveal-avascular-zone-area-measurements-using-optical-coherence-tomography-angiography
#9
Danuta M Sampson, Peijun Gong, Di An, Moreno Menghini, Alex Hansen, David A Mackey, David D Sampson, Fred K Chen
Purpose: To evaluate the impact of image magnification correction on superficial retinal vessel density (SRVD) and foveal avascular zone area (FAZA) measurements using optical coherence tomography angiography (OCTA). Methods: Participants with healthy retinas were recruited for ocular biometry, refraction, and RTVue XR Avanti OCTA imaging with the 3 × 3-mm protocol. The foveal and parafoveal SRVD and FAZA were quantified with custom software before and after correction for magnification error using the Littman and the modified Bennett formulae...
June 1, 2017: Investigative Ophthalmology & Visual Science
https://www.readbyqxmd.com/read/28622313/optical-coherence-tomography-analysis-of-evolution-of-bruch-s-membrane-features-in-angioid-streaks
#10
A Marchese, M Parravano, A Rabiolo, A Carnevali, E Corbelli, M V Cicinelli, M Battaglia Parodi, L Querques, F Bandello, G Querques
PurposeTo describe optical coherence tomography (OCT) features in the Bruch's membrane (BM) of eyes with angioid streaks (AS) and evaluate their evolution over the follow-up.Patients and methodsPatients with AS presenting between March 2016 and September 2016 at two tertiary referral centers were consecutively recruited in this study. Eligibility criteria included prior spectral domain (SD)-OCT images, taken at least 3 months before at the same referral center, with automated eye tracking and image alignment modules...
June 16, 2017: Eye
https://www.readbyqxmd.com/read/28622198/ocular-sarcoidosis-new-diagnostic-modalities-and-treatment
#11
Sung J Yang, Sherveen Salek, James T Rosenbaum
PURPOSE OF REVIEW: Ocular involvement in sarcoidosis is present in up to 80% of patients and is frequently manifested before diagnosis of the underlying systemic disease. Considering the therapeutic consequences, early diagnosis of the underlying disease is advantageous in patients presenting with ocular inflammation. There are several ocular findings suggestive of underlying sarcoidosis, such as granulomatous keratic precipitates, iris nodules, cells in the vitreous humor known as snowballs and snowbanks, and retinal periphlebitis...
June 15, 2017: Current Opinion in Pulmonary Medicine
https://www.readbyqxmd.com/read/28615925/anterior-lamina-cribrosa-surface-depth-in-healthy-saudi-females
#12
Amira El-Agamy, Fayrouz Oteaf, Mohamed Berika
PURPOSE: This study was conducted to determine normative profile of anterior lamina cribrosa surface depth (ALCSD) in healthy Saudi females using Topcon Three-Dimensional (3D) Optical Coherence Tomography (OCT) 2000 - Spectral Domain (SD-OCT). In addition, the correlation between ALCSD and other clinical factors such as age, refractive error, intraocular pressure (IOP), central corneal thickness, anterior chamber depth, axial length, retinal nerve fiber layer thickness, and disk area was also assessed...
2017: Clinical Ophthalmology
https://www.readbyqxmd.com/read/28613219/repeatability-of-automated-vessel-density-and-superficial-and-deep-foveal-avascular-zone-area-measurements-using-optical-coherence-tomography-angiography-diurnal-findings
#13
Özge Yanik Odabaş, Sibel Demirel, Emin Özmert, Figen Batıoğlu
PURPOSE: To evaluate the repeatability of vessel density and superficial and deep foveal avascular zone measurements using optical coherence tomography angiography, and to specify a diurnal change range. METHODS: Forty-six eyes of 25 healthy individuals were included. Optical coherence tomography angiography measurements were planned for three consecutive sessions, with 3 hours in between them. AngioVue software of the RTVue XR Avanti was used. Superficial and deep retinal layer vessel density values, including the whole retina, fovea, and each parafoveal zone, were obtained from the software...
May 2, 2017: Retina
https://www.readbyqxmd.com/read/28611153/effects-of-short-term-mild-hypercapnia-during-head-down-tilt-on-intracranial-pressure-and-ocular-structures-in-healthy-human-subjects
#14
Steven S Laurie, Gianmarco Vizzeri, Giovanni Taibbi, Connor R Ferguson, Xiao Hu, Stuart M C Lee, Robert Ploutz-Snyder, Scott M Smith, Sara R Zwart, Michael B Stenger
Many astronauts experience ocular structural and functional changes during long-duration spaceflight, including choroidal folds, optic disc edema, globe flattening, optic nerve sheath diameter (ONSD) distension, retinal nerve fiber layer thickening, and decreased visual acuity. The leading hypothesis suggests that weightlessness-induced cephalad fluid shifts increase intracranial pressure (ICP), which contributes to the ocular structural changes, but elevated ambient CO2 levels on the International Space Station may also be a factor...
June 2017: Physiological Reports
https://www.readbyqxmd.com/read/28607772/dark-signals-in-the-choroidal-vasculature-on-optical-coherence-tomography-angiography-an-artefact-or-not
#15
REVIEW
Rui Hua, Hailin Wang
Optical coherence tomography angiography (OCTA) based on mathematical processing of sequentially acquired structural OCT images has been applied widely in both retinal and choroidal research and may have advantages over traditional angiography. Images obtained by OCTA are rendered under the assumption that the only moving entity in the retina is blood flow. Optical phenomena and image processing algorithms may create imaging artefacts. Therefore, OCTA images require careful interpretation. This review discusses the dark signals seen in the choroidal vasculature on OCTA using multiple factor analysis...
2017: Journal of Ophthalmology
https://www.readbyqxmd.com/read/28606456/extended-depth-of-focus-contact-lenses-vs-two-commercial-multifocals-part-1-optical-performance-evaluation-via-computed-through-focus-retinal-image-quality-metrics
#16
Ravi C Bakaraju, Klaus Ehrmann, Arthur Ho
PURPOSE: To compare the computed optical performance of prototype lenses designed using deliberate manipulation of higher-order spherical aberrations to extend depth-of-focus (EDOF) with two commercial multifocals. METHODS: Emmetropic, presbyopic, schematic eyes were coupled with prototype EDOF and commercial multifocal lenses (Acuvue Oasys for presbyopia, AOP, Johnson & Johnson & Air Optix Aqua multifocal, AOMF, Alcon). For each test configuration, the through-focus retinal image quality (TFRIQ) values were computed over 21 vergences, ranging from -0...
June 9, 2017: Journal of Optometry
https://www.readbyqxmd.com/read/28604982/edi-oct-evaluation-of-choroidal-thickness-in-retinitis-pigmentosa
#17
Andrea Sodi, Chiara Lenzetti, Vittoria Murro, Orsola Caporossi, Dario P Mucciolo, Daniela Bacherini, Francesca Cipollini, Ilaria Passerini, Gianni Virgili, Stanislao Rizzo
PURPOSE: To evaluate choroidal thickness (CT) in retinitis pigmentosa (RP) using enhanced depth imaging (EDI) optical coherence tomography (OCT). METHODS: A retrospective analysis of a group of patients with RP who underwent EDI-OCT was performed. Choroidal thickness measurements were compared with those of age- and sex-matched healthy subjects. In the RP group, the possible association between subfoveal CT and some clinical parameters (visual acuity, age, age at disease onset, duration of the disease, macular thickness, visual field loss, electroretinography [ERG]) was evaluated...
June 9, 2017: European Journal of Ophthalmology
https://www.readbyqxmd.com/read/28595892/localization-of-optic-disc-and-fovea-in-retinal-images-using-intensity-based-line-scanning-analysis
#18
Ravi Kamble, Manesh Kokare, Girish Deshmukh, Fawnizu Azmadi Hussin, Fabrice Mériaudeau
Accurate detection of diabetic retinopathy (DR) mainly depends on identification of retinal landmarks such as optic disc and fovea. Present methods suffer from challenges like less accuracy and high computational complexity. To address this issue, this paper presents a novel approach for fast and accurate localization of optic disc (OD) and fovea using one-dimensional scanned intensity profile analysis. The proposed method utilizes both time and frequency domain information effectively for localization of OD...
April 27, 2017: Computers in Biology and Medicine
https://www.readbyqxmd.com/read/28592811/evaluating-the-impact-of-vitreomacular-adhesion-on-anti-vegf-therapy-for-retinal-vein-occlusion-using-machine-learning
#19
Sebastian M Waldstein, Alessio Montuoro, Dominika Podkowinski, Ana-Maria Philip, Bianca S Gerendas, Hrvoje Bogunovic, Ursula Schmidt-Erfurth
Vitreomacular adhesion (VMA) represents a prognostic biomarker in the management of exudative macular disease using anti-vascular endothelial growth factor (VEGF) agents. However, manual evaluation of VMA in 3D optical coherence tomography (OCT) is laborious and data on its impact on therapy of retinal vein occlusion (RVO) are limited. The aim of this study was to (1) develop a fully automated segmentation algorithm for the posterior vitreous boundary and (2) to study the effect of VMA on anti-VEGF therapy for RVO...
June 7, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28592309/machine-learning-techniques-for-diabetic-macular-edema-dme-classification-on-sd-oct-images
#20
Khaled Alsaih, Guillaume Lemaitre, Mojdeh Rastgoo, Joan Massich, Désiré Sidibé, Fabrice Meriaudeau
BACKGROUND: Spectral domain optical coherence tomography (OCT) (SD-OCT) is most widely imaging equipment used in ophthalmology to detect diabetic macular edema (DME). Indeed, it offers an accurate visualization of the morphology of the retina as well as the retina layers. METHODS: The dataset used in this study has been acquired by the Singapore Eye Research Institute (SERI), using CIRRUS TM (Carl Zeiss Meditec, Inc., Dublin, CA, USA) SD-OCT device. The dataset consists of 32 OCT volumes (16 DME and 16 normal cases)...
June 7, 2017: Biomedical Engineering Online
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