1. 1-24 of 186 1 2 3 4 5 6 7 8 »
    1. Automated detection of a nonperfusion area caused by retinal vein occlusion in optical coherence tomography angiography images using deep learning

      Automated detection of a nonperfusion area caused by retinal vein occlusion in optical coherence tomography angiography images using deep learning

      We aimed to assess the ability of deep learning (DL) and support vector machine (SVM) to detect a nonperfusion area (NPA) caused by retinal vein occlusion (RVO) with optical coherence tomography angiography (OCTA) images. The study included 322 OCTA images (normal: 148; NPA owing to RVO: 174 [128 branch RVO images and 46 central RVO images]). Training to construct the DL model using deep convolutional neural network (DNN) algorithms was provided using OCTA images. The SVM used a scikit-learn library with a radial basis function kernel. The area under the curve (AUC), sensitivity and specificity for detecting an NPA were ...

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    2. OCT-Angiography: Mydriatic phenylephrine and tropicamide do not influence retinal microvasculature in macula and peripapillary region

      OCT-Angiography: Mydriatic phenylephrine and tropicamide do not influence retinal microvasculature in macula and peripapillary region

      Purpose Optical coherence tomography angiography (OCT-A) enables visualization of retinal microcirculation. As a potential influence of mydriatic eye drops on retinal vessel density (VD) was proposed, the purpose of the present study was to investigate an influence of 5% phenylephrine and 0.5% tropicamide on macula and peripapillary VD. Methods 30 eyes of 30 healthy persons were measured by en face OCT-A (Spectralis OCT II, Heidelberg Engineering, Heidelberg). Scans of the macula (12 sectors, region of interest, ROI: 6.10 mm 2 ) and peripapillary region (4 sectors, ROI: 2.67 mm 2 ) were performed before (-) and 30 minutes after application ...

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    3. Comparison of corneal elevation and pachymetry measurements made by two state of the art corneal tomographers with different measurement principles

      Comparison of corneal elevation and pachymetry measurements made by two state of the art corneal tomographers with different measurement principles

      Purpose To compare corneal tomography measurements (elevation and pachymetry) as made by two corneal tomographers: Pentacam AXL and CASIA 2. Material and methods The devices were used in a standard measuring mode. 77 normal eyes were measured five times with both devices. The data maps for anterior and posterior corneal elevation and pachymetry were exported and analyzed. Repeatability and average values were calculated for each valid data point on the exported data maps. We also calculated a corrected repeatability of the elevation data maps by removing rotation, tilt, and decentration through realignment of the elevation measurement of each eye prior ...

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    4. Comparison of two swept-source optical coherence tomography biometers and a partial coherence interferometer

      Comparison of two swept-source optical coherence tomography biometers and a partial coherence interferometer

      Purpose To compare biometry and prediction of postoperative refractive outcomes obtained by two swept-source optical coherence tomography (SS-OCT) biometers (IOLMaster 700 and Argos), and a partial coherence interferometry (IOLMaster ver 5.4) Methods Biometric values were measured using two SS-OCT and PCI device and evaluated against one another. Predictive errors were compared at one month after cataract surgery. Results One hundred forty six eyes were considered. Axial length (AXL) measurements were not successful in 3 eyes measured by IOLMaster 700 and Argos devices, and in 17 eyes measured by IOLMaster ver. 5.4 devices. AXL as measured by Argos showed ...

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    5. Differences in macular capillary parameters between healthy black and white subjects with Optical Coherence Tomography Angiography (OCTA)

      Differences in macular capillary parameters between healthy black and white subjects with Optical Coherence Tomography Angiography (OCTA)

      Purpose To investigate if there are differences in macular capillaries between black and white subjects using optical coherence tomography angiography (OCTA) and identify potential factors underlying the epidemiologically-based higher vulnerability of black populations to diabetic retinopathy (DR). Methods This prospective, observational cross-sectional study included 93 eyes of 47 healthy subjects with no medical history and ocular history who self-identified as black or white and were matched for age, sex, refractive error, and image quality. Subjects underwent OCTA imaging (RTVue-XR Avanti) of the superficial (SCP) and deep (DCP) capillary plexuses and choriocapillaris. AngioAnalytics was used to analyze vessel density (VD) and ...

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    6. Macular thickness measurements of healthy, naïve cynomolgus monkeys assessed with spectral-domain optical coherence tomography (SD-OCT)

      Macular thickness measurements of healthy, naïve cynomolgus monkeys assessed with spectral-domain optical coherence tomography (SD-OCT)

      The purpose of this study was to measure central macular thickness in an unprecedented number of cynomolgus monkeys. Macular thickness was measured with Heidelberg spectral-domain OCT in 320 eyes of healthy and treatment-naïve cynomolgus monkeys (80 males and 80 females). The macula was successfully measured in all 320 eyes. Macular thickness was not significantly different between the sexes. The mean central macular thickness was 244 μm (+/- 21 μm). Macular thicknesses in the quadrants were 327 +/-17 μm (temporal inner), 339 +/- 17 μm (inferior inner), 341 +/- 14 μm (superior inner), 341 +/-18 μm (nasal inner), and 299 +/- 20 μm (temporal ...

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    7. Influence of mydriasis on optical coherence tomography angiography imaging in patients with age-related macular degeneration

      Influence of mydriasis on optical coherence tomography angiography imaging in patients with age-related macular degeneration

      Purpose To evaluate the effect of topical mydriatic eye drops on optical coherence tomography angiography (OCTA) parameters in patients with age-related macular degeneration (AMD). Methods 27 eyes of 27 patients suffering from AMD were included in this cross-sectional study. Patients with ≥-4.5 diopters spherical equivalent, corneal opacities or dense cataract preventing high-quality imaging were excluded. Whole-en-face scans of the superficial capillary plexus (SCP) and deep capillary plexus (DCP) in the central 3x3mm foveal region as well as whole-en-face and peripapillary scans of the radial peripapillary capillaries (RPC) were generated using OCTA (AngioVue®, Optovue). Imaging was first conducted with patients ...

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    8. Reliability of Intra-Retinal Layer Thickness Estimates

      Reliability of Intra-Retinal Layer Thickness Estimates

      Purpose Measurement of intra-retinal layer thickness using optical coherence tomography (OCT) has become increasingly prominent in multiple sclerosis (MS) research. Nevertheless, the approaches used for determining the mean layer thicknesses vary greatly. Insufficient data exist on the reliability of different thickness estimates, which is crucial for their application in clinical studies. This study addresses this lack by evaluating the repeatability of different thickness estimates. Methods Studies that used intra-retinal layer segmentation of macular OCT scans in patients with MS were retrieved from PubMed. To investigate the repeatability of previously applied layer estimation approaches, we generated datasets of repeating measurements of ...

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    9. Quantitative measures of corneal transparency, derived from objective analysis of depth-resolved corneal images, demonstrated with full-field optical coherence tomographic microscopy

      Quantitative measures of corneal transparency, derived from objective analysis of depth-resolved corneal images, demonstrated with full-field optical coherence tomographic microscopy

      Loss of corneal transparency, as occurs with various pathologies, infections, immune reactions, trauma, aging, and surgery, is a major cause of visual handicap worldwide. However, current means to assess corneal transparency are extremely limited and clinical and eye-bank practice usually involve a subjective and qualitative observation of opacities, sometimes with comparison against an arbitrary grading scale, by means of slit-lamp biomicroscopy. Here, we describe a novel objective optical data analysis-based method that enables quantifiable and standardized characterization of corneal transparency from depth-resolved corneal images, addressing the demand for such a means in both the laboratory and clinical ophthalmology setting. Our ...

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    10. Repeatability of quantitative measurements of retinal layers with SD-OCT and agreement between vertical and horizontal scan protocols in healthy eyes

      Repeatability of quantitative measurements of retinal layers with SD-OCT and agreement between vertical and horizontal scan protocols in healthy eyes

      Purpose To evaluate the repeatability of the new spectral domain optical coherence tomography (HOCT-1F), and also to evaluate the agreement between vertical and horizontal scan protocols. In addition, we also evaluated the relation between the repeatability and age. Methods Three consecutive measurements of the inner limiting membrane–retinal pigment epithelium (ILM-RPE), inner limiting membrane–inner plexiform layer (ILM-IPL) from macular horizontal and vertical scans, and inner limiting membrane–retinal nerve fiber layer (ILM-RNFL) from optic disc horizontal scan. 159 subjects were included in the analysis. The within subject standard deviation (Sw) and the repeatability limits (R limit ) are used to ...

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    11. Validation of automated artificial intelligence segmentation of optical coherence tomography images

      Validation of automated artificial intelligence segmentation of optical coherence tomography images

      Purpose To benchmark the human and machine performance of spectral-domain (SD) and swept-source (SS) optical coherence tomography (OCT) image segmentation, i.e., pixel-wise classification, for the compartments vitreous, retina, choroid, sclera. Methods A convolutional neural network (CNN) was trained on OCT B-scan images annotated by a senior ground truth expert retina specialist to segment the posterior eye compartments. Independent benchmark data sets (30 SDOCT and 30 SSOCT) were manually segmented by three classes of graders with varying levels of ophthalmic proficiencies. Nine graders contributed to benchmark an additional 60 images in three consecutive runs. Inter-human and intra-human class agreement was ...

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    12. Exploring the relationship between collaterals and vessel density in retinal vein occlusions using optical coherence tomography angiography

      Exploring the relationship between collaterals and vessel density in retinal vein occlusions using optical coherence tomography angiography

      Purpose To characterize the types of collaterals in eyes with retinal vein occlusion (RVO) and further investigate their correlations with vessel densities of the superficial (SCP) and the deep capillary plexus (DCP) using optical coherence tomography angiography (OCTA). Methods This cross-sectional study included 25 eyes of 23 patients with RVO. 3 x 3 mm 2 OCTA macular scans were used to quantify the parafoveal vessel density (VD) of the SCP and DCP, and to classify the collaterals into one of four types (true superficial, true deep, superficial diving, and foveal collateral). Generalized estimating equation (GEE) regression analysis was performed to ...

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    13. Optical coherence tomography angiography of superficial retinal vessel density and foveal avascular zone in myopic children

      Optical coherence tomography angiography of superficial retinal vessel density and foveal avascular zone in myopic children

      Purpose To assess the superficial retinal vessel density (SRVD) and foveal avascular zone (FAZ) in myopic children using optical coherence tomography angiography (OCTA). Methods 174 eyes of 89 subjects with myopia and 101 eyes of 54 age-matched, emmetropic volunteers (control group) were enrolled in this study. The mean age of the subjects and controls was 13.9 (SD ± 2.3) and 13.1 (SD ± 2.4), respectively. Myopia was defined as spherical equivalent <– 1.0 diopter. Emmetropic subjects were defined as having spherical equivalent from + 0.5 to − 0.5 diopter. The mean axial length (AL) in myopic patients was ...

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    14. A feature agnostic approach for glaucoma detection in OCT volumes

      A feature agnostic approach for glaucoma detection in OCT volumes

      Optical coherence tomography (OCT) based measurements of retinal layer thickness, such as the retinal nerve fibre layer (RNFL) and the ganglion cell with inner plexiform layer (GCIPL) are commonly employed for the diagnosis and monitoring of glaucoma. Previously, machine learning techniques have relied on segmentation-based imaging features such as the peripapillary RNFL thickness and the cup-to-disc ratio. Here, we propose a deep learning technique that classifies eyes as healthy or glaucomatous directly from raw, unsegmented OCT volumes of the optic nerve head (ONH) using a 3D Convolutional Neural Network (CNN). We compared the accuracy of this technique with various feature-based ...

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    15. Optical coherence tomography angiography characteristics of choroidal neovascularization requiring varied dosing frequencies in treat-and-extend management: An analysis of the AVATAR study

      Optical coherence tomography angiography characteristics of choroidal neovascularization requiring varied dosing frequencies in treat-and-extend management: An analysis of the AVATAR study

      Purpose To evaluate optical coherence tomography angiography (OCTA) characteristics of choroidal neovascularization (CNV) in eyes requiring different treatment frequency of anti-vascular endothelial growth factor (VEGF) therapy for neovascular age-related macular degeneration (NVAMD). Design Prospective observational case series. Methods Subjects who had undergone anti-VEGF treatment for NVAMD in the AVATAR study were subdivided into 3 groups depending on required anti-VEGF dosing: (i) treat-and-extend requiring every 4–6 weeks dosing (TEq4-6w), (ii) treat-and-extend requiring every 7–12 weeks dosing (TEq7-12w), (iii) eyes not requiring injection within last 12 months (PRN >12mo). OCTA images were evaluated for the morphological characteristics of CNV and ...

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    16. Retinal texture biomarkers may help to discriminate between Alzheimer’s, Parkinson’s, and healthy controls

      Retinal texture biomarkers may help to discriminate between Alzheimer’s, Parkinson’s, and healthy controls

      A top priority in biomarker development for Alzheimer’s disease (AD) and Parkinson’s disease (PD) is the focus on early diagnosis, where the use of the retina is a promising avenue of research. We computed fundus images from optical coherence tomography (OCT) data and analysed the structural arrangement of the retinal tissue using texture metrics. We built clinical class classification models to distinguish between healthy controls (HC), AD, and PD, using machine learning (support vector machines). Median sensitivity is 88.7%, 79.5% and 77.8%, for HC, AD, and PD eyes, respectively. When the same subject has the ...

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    17. Posterior staphylomas and scleral curvature in highly myopic children and adolescents investigated by ultra-widefield optical coherence tomography

      Posterior staphylomas and scleral curvature in highly myopic children and adolescents investigated by ultra-widefield optical coherence tomography

      Purpose To determine the early signs of posterior staphylomas in highly myopic eyes of younger subjects by swept-source ultra-widefield optical coherence tomography (WF-OCT). Methods This was an observational case series study. Highly myopic subjects younger than 20 years old who were examined consecutively by prototype WF-OCT were studied. High myopia was defined according to the Ministry of Health and Welfare, Japan classification. A posterior displacement of the sclera and two OCT features indicating the staphyloma edges were used as markers of a staphyloma. Results Fifty-five eyes of 30 patients with the mean age of 12.3 years, and the mean ...

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    18. Comparison of foveal avascular zone between optical coherence tomography angiography and fluorescein angiography in patients with retinal vein occlusion

      Comparison of foveal avascular zone between optical coherence tomography angiography and fluorescein angiography in patients with retinal vein occlusion

      Objective To compare area of foveal avascular zone (FAZ) in different retinal vascular layers in optical coherence tomography angiography (OCTA) and fluorescein angiography (FA) in patients with retinal vein occlusion (RVO). Design and methods Prospective cross-sectional comparative study in 47 eyes of 47 patients. FA was recorded with the Zeiss FF450plusIR camera and OCTA was obtained with the Zeiss Cirrus 5000 equipped with the AngioPlex module. Area of FAZ was graded by two independent investigators and calculated with Adobe Photoshop. Analysis for the total study population as well as subgroup analysis for branch retinal vein occlusion (BRVO), central retinal vein ...

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    19. Determination of iris thickness development in children using swept-source anterior-segment optical coherence tomography

      Determination of iris thickness development in children using swept-source anterior-segment optical coherence tomography

      Purpose The uvea comprises the iris, ciliary body, and choroid. However, the development of the anterior part (iris and ciliary body) in children is not yet fully elucidated. We investigated the iris thickness (IT) in children using swept-source anterior-segment optical coherence tomography (ASOCT). Methods In this retrospective, clinic-based study, we enrolled 41 children (mean ± standard deviation: 6.8 ± 3.3 years; range: 3–16; 17 males) with normal or mild refractive error. Horizontal scanning images of swept-source ASOCT were analyzed in temporal and nasal angle areas. The ITs at 1 and 2 mm from the pupil edge were measured using ...

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    20. Projection resolved optical coherence tomography angiography to distinguish flow signal in retinal angiomatous proliferation from flow artifact

      Projection resolved optical coherence tomography angiography to distinguish flow signal in retinal angiomatous proliferation from flow artifact

      Purpose To investigate whether hyperreflective foci (HRF) exhibit flow projection artifact on OCTA, and study the efficacy of commercial projection artifact removal software (PAR-OCTA, Optovue, Inc), and a custom projection resolved OCTA (PR-OCTA) in distinguishing artifacts from true flow in retinal angiomatous proliferation (RAP). Methods The study included five eyes with HRF representing pigment migration in dry age-related macular degeneration (AMD), five eyes with leaking treatment- naïve RAP, and ten eyes with diabetic hard exudates. We examined flow signal on OCTA cross-sections using PAR, and performed PR-OCTA to study the effect of increasingly stringent projection removal thresholds. Flow signal ...

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    21. Swept source optical coherence tomography to early detect multiple sclerosis disease. The use of machine learning techniques

      Swept source optical coherence tomography to early detect multiple sclerosis disease. The use of machine learning techniques

      Objective To compare axonal loss in ganglion cells detected with swept-source optical coherence tomography (SS-OCT) in eyes of patients with multiple sclerosis (MS) versus healthy controls using different machine learning techniques. To analyze the capability of machine learning techniques to improve the detection of retinal nerve fiber layer (RNFL) and the complex Ganglion Cell Layer–Inner plexiform layer (GCL+) damage in patients with multiple sclerosis and to use the SS-OCT as a biomarker to early predict this disease. Methods Patients with relapsing-remitting MS (n = 80) and age-matched healthy controls (n = 180) were enrolled. Different protocols from the DRI SS-OCT Triton ...

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    22. Vascular maturity of type 1 and type 2 choroidal neovascularization evaluated by optical coherence tomography angiography

      Vascular maturity of type 1 and type 2 choroidal neovascularization evaluated by optical coherence tomography angiography

      Purpose Vessel maturation is considered to proceed by pruning branches resulting in less branching vessels. This study investigated the vessel junction densities of type 1 and type 2 choroidal neovascularizations (CNVs) using optical coherence tomography angiography (OCTA). Methods We collected consecutive data from treatment-naïve eyes diagnosed with typical age-related macular degeneration (AMD). The OCTA images with CNV were analyzed to calculate vessel areas, vessel lengths, and vessel junction densities. Results Of 60 eyes in 60 patients, type 1 CNV diagnoses had been made in 40 eyes, and type 2 CNV in 20 eyes. We found no significant difference in ...

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    23. Comparison of wide field optical coherence tomography angiography with extended field imaging and fluorescein angiography in retinal vascular disorders

      Comparison of wide field optical coherence tomography angiography with extended field imaging and fluorescein angiography in retinal vascular disorders

      Purpose To compare swept source OCTA device, with and without the extended field imaging (EFI) technique, to standard fluorescein angiography (FA) in the clinical practice. Methods Consecutive patients with vascular disorder patients underwent FA with 55-degree lens (Spectralis Heidelberg Engineering, Heidelberg, Germany) and OCTA with the prototype PlexElite (Carl Zeiss Meditec, Dublin, CA) using a 12 mm x 12 mm volume scan pattern centered on the fovea and a prototype of + 20.00-diopter designed specifically by Zeiss. The imaging methods were compared for visible field of view, extension of non-perfused areas, presence and number of neovessels, vessel density (VD) and ...

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    24. Optical coherence tomography for observing development of pulmonary arterial vasa vasorum after bidirectional cavopulmonary connection in children

      Optical coherence tomography for observing development of pulmonary arterial vasa vasorum after bidirectional cavopulmonary connection in children

      Background Hypoxia and low pulmonary arterial (PA) blood flow stimulate the development of systemic-to-pulmonary collateral blood vessels, which can be an adverse factor when performing the Fontan operation. The aim of this study was to use optical coherence tomography (OCT) to elucidate the morphological changes in PA vasculature after creation of a bidirectional cavopulmonary connection (BCPC) in children. Methods This prospective study evaluated PA wall thickness and development of PA vasa vasorum (VV) in the distal PA of eight patients (BCPC group, 1.3 ± 0.3 years) and 20 age-matched children with normal pulmonary artery hemodynamics and morphology (Control group ...

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