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    1. High speed, long range, deep penetration swept source OCT for structural and angiographic imaging of the anterior eye

      High speed, long range, deep penetration swept source OCT for structural and angiographic imaging of the anterior eye

      This study reports the development of prototype swept-source optical coherence tomography (SS-OCT) technology for imaging the anterior eye. Advances in vertical-cavity surface-emitting laser (VCSEL) light sources, signal processing, optics and mechanical designs, enable a unique combination of high speed, long range, and deep penetration that addresses the challenges of anterior eye imaging. We demonstrate SS-OCT with a 325 kHz A-scan rate, 12.2 µm axial resolution (in air), and 15.5 mm depth range (in air) at 1310 nm wavelength. The ultrahigh 325 kHz A-scan rate not only facilitates biometry measurements by minimizing acquisition time and thus reducing motion, but ...

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    2. Agreement of different OCT scan directions for individual retinal-layer thickness measurements in multiple sclerosis subjects with prior unilateral optic neuritis

      Agreement of different OCT scan directions for individual retinal-layer thickness measurements in multiple sclerosis subjects with prior unilateral optic neuritis

      The similarities between horizontal and vertical Optical Coherence Tomography (OCT) scans for the individual retinal layer thickness measurements in the macula was evaluated. Two volumetric scans (B-scans oriented horizontally and vertically) were performed in 64 multiple sclerosis subjects with history of unilateral optic neuritis and 64 healthy controls. The agreement between the thickness measurements with horizontal and vertical OCT scans was evaluated in 3 groups of eyes: healthy controls, eyes with history of optic neuritis and the fellow eyes. The mean difference in individual layer thickness between the scans was smaller than the instrument's axial resolution in all 3 ...

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    3. Thickness of retinal pigment epithelium–Bruch’s membrane complex in adult Chinese using optical coherence tomography

      Thickness of retinal pigment epithelium–Bruch’s membrane complex in adult Chinese using optical coherence tomography

      Purpose To study thickness of RPE–BM complex in adult Chinese subjects and its correlation with systemic and ocular biometric parameters. Design Population-based longitudinal study. Cross-sectional study. Participants The population-based Beijing Eye Study 2011 included 3468 individuals with a mean age of 64.6 ± 9.8 years (range: 50–93 years). Methods A detailed ophthalmic examination was performed including spectral-domain optical coherence tomography (SD OCT) for measurement of the thickness of RPE–BM complex. Use Heidelberg software “Heidelberg Eye Explorer” for segmentation and measurements. Main outcome measure Thickness of RPE–BM complex. Results In total, 3276 people (6530 eyes) were ...

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    4. Interocular symmetry of optical coherence tomography parameters in healthy children and adolescents

      Interocular symmetry of optical coherence tomography parameters in healthy children and adolescents

      Evaluation of interocular asymmetry of optical coherence tomography (OCT) parameters is important for the glaucoma and optic neuropathies. This study was performed to evaluate the interocular asymmetry of OCT parameters in healthy children and adolescents. The circumpapillary retinal nerve fiber layer (RNFL) thickness, optic nerve head (ONH) parameters, and macular ganglion cell-inner plexiform layer (GCIPL) thickness were measured in 620 eyes of 310 healthy children and adolescents using Cirrus HD-OCT. The interocular asymmetry (right eye–left eye) in the OCT parameters was analyzed. The mean ± standard deviation age was 10.3 ± 3.7 years (range 5–17). The right eyes ...

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    5. Retrospective analysis of OCT on MB characteristics and 1-year follow-up of the ISR incidence after the DES implantation in patients with MB

      Retrospective analysis of OCT on MB characteristics and 1-year follow-up of the ISR incidence after the DES implantation in patients with MB

      We used optical coherence tomography (OCT) to analyze the "half-moon" like phenomenon and its characteristics and observe 1-year follow-up of the in-stent restenosis (ISR) incidence after the drug eluted stent (DES) implantation in patients with the myocardial bridge (MB). Patients were retrospectively analyzed from January 2013 to December 2019. We used OCT to check 45 patients with MB and found a visible muscle layer (VML) around the vessel adventitia with the same or high density compared to the vessel media layer. There was not any significant difference in maximal thickness, maximal arch, and total length between the half-moon layer and ...

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    6. Peripapillary and macular vascular parameters by optical coherence tomography angiography in primary congenital glaucoma

      Peripapillary and macular vascular parameters by optical coherence tomography angiography in primary congenital glaucoma

      Objective: To evaluate the differences in peripapillary and macular vascular parameters by optical coherence tomography angiography (OCTA) between patients with primary congenital glaucoma (PCG) and healthy controls; and to determine their diagnostic accuracy. Material and methods: Observational, cross-sectional study including 39 eyes with PCG and 78 healthy eyes. Only one eye per patient was included. All included patients underwent a comprehensive ophthalmic examination and peripapillary and macular analysis were performed by Angioplex TM OCTA (Cirrus HD-OCT 5000) with a 4.5 × 4.5 mm optic nerve head scan and 6 × 6 mm macular scan. Global data and quadrant data from ...

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    7. Non-invasive scoring of cellular atypia in keratinocyte cancers in 3D LC-OCT images using Deep Learning

      Non-invasive scoring of cellular atypia in keratinocyte cancers in 3D LC-OCT images using Deep Learning

      Diagnosis based on histopathology for skin cancer detection is today's gold standard and relies on the presence or absence of biomarkers and cellular atypia. However it suffers drawbacks: it requires a strong expertise and is time-consuming. Moreover the notion of atypia or dysplasia of the visible cells used for diagnosis is very subjective, with poor inter-rater agreement reported in the literature. Lastly, histology requires a biopsy which is an invasive procedure and only captures a small sample of the lesion, which is insufficient in the context of large fields of cancerization. Here we demonstrate that the notion of cellular ...

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    8. Classifying central serous chorioretinopathy subtypes with a deep neural network using optical coherence tomography images: a cross-sectional study

      Classifying central serous chorioretinopathy subtypes with a deep neural network using optical coherence tomography images: a cross-sectional study

      Central serous chorioretinopathy (CSC) is the fourth most common retinopathy and can reduce quality of life. CSC is assessed using optical coherence tomography (OCT), but deep learning systems have not been used to classify CSC subtypes. This study aimed to build a deep learning system model to distinguish CSC subtypes using a convolutional neural network (CNN). We enrolled 435 patients with CSC from a single tertiary center between January 2015 and January 2020. Data from spectral domain OCT (SD-OCT) images of the patients were analyzed using a deep CNN. Five-fold cross-validation was employed to evaluate the model's ability to ...

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    9. Scalable mapping of myelin and neuron density in the human brain with micrometer resolution

      Scalable mapping of myelin and neuron density in the human brain with micrometer resolution

      Optical coherence tomography (OCT) is an emerging 3D imaging technique that allows quantification of intrinsic optical properties such as scattering coefficient and back-scattering coefficient, and has proved useful in distinguishing delicate microstructures in the human brain. The origins of scattering in brain tissues are contributed by the myelin content, neuron size and density primarily; however, no quantitative relationships between them have been reported, which hampers the use of OCT in fundamental studies of architectonic areas in the human brain and the pathological evaluations of diseases. Here, we built a generalized linear model based on Mie scattering theory that quantitatively links ...

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    10. Accessible artificial intelligence for ophthalmologists

      Accessible artificial intelligence for ophthalmologists

      Artificial intelligence (AI) is starting to be widely leveraged for ophthalmic classification tasks [ 1 , 2 , 3 ]. One of the primary goals of such technology is to aid ophthalmologists and optometrists in the more accurate and timely management of disease. Thus, research mainly targets the development of AI systems to target image intensive clinical data such as optical coherence tomography (OCT) classification to fundoscopy image recognition and segmentation. While these studies have proven high levels of accuracy and the ability to be potentially clinically beneficial, we feel as though more work should be focused on the accessibility of such technologies for ...

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    11. Handheld optical coherence tomography removes barriers to imaging the eyes of young children

      Handheld optical coherence tomography removes barriers to imaging the eyes of young children

      Optical coherence tomography (OCT) has revolutionised the clinical practice of ophthalmology. Its use has become widespread across most major branches of ophthalmology, including medical retina, surgical retina, glaucoma, neuro-ophthalmology, uveitis, cornea, anterior segment and refractive surgery, primary care ophthalmology and ocular oncology. However, conventional table-mounted OCT devices are not designed for infants and young children, who have previously been deprived of this technology and its many clinical benefits. Furthermore, many research studies using table-mounted OCT devices have previously excluded infants and young children. Nicholson et al. [ 1 ] successfully used handheld spectral-domain OCT in a cohort of children with Down syndrome ...

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    12. Segmentation of the foveal and parafoveal retinal architecture using handheld spectral-domain optical coherence tomography in children with Down syndrome

      Segmentation of the foveal and parafoveal retinal architecture using handheld spectral-domain optical coherence tomography in children with Down syndrome

      Background Down syndrome is a common multigene, multisystem disorder associated with abnormalities of visual function and characteristic changes in the majority of tissues in the eye. Historic descriptions of macular structure in Down syndrome have been variable, but optical coherence tomography allows increasingly detailed characterization of retinal architecture in vivo. We demonstrate the feasibility of retinal imaging in children with Down syndrome using handheld OCT in an outpatient clinical setting, and describe the foveal and parafoveal retinal architecture in this group. Methods Fourteen White British children aged between 4 and 11 with Down syndrome were recruited to have handheld SD-OCT ...

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    13. Predictive role of optical coherence tomography angiography for exudation recurrence in patients with type 1 neovascular age-related macular degeneration treated with pro-re-nata protocol

      Predictive role of optical coherence tomography angiography for exudation recurrence in patients with type 1 neovascular age-related macular degeneration treated with pro-re-nata protocol

      Objectives We sought to identify the consecutive changes and predictive features for exudation recurrence in macular neovascularization (MNV) using optical coherence tomography angiography (OCTA) in type 1 neovascular age-related macular degeneration (NVAMD). Methods A total of 291 OCTA images in consecutive visit of 45 patients newly diagnosed with type 1 NMV and treated with three loading intravitreal anti–vascular endothelial growth factor injections (IVIs) and a pro-re-nata (PRN) therapy regimen were analysed. Quantitative features of OCTA included the MNV area, MNV length, total number of endpoints (open-ended vessels) and junctions (internal branching) using AngioTool. Two subgroups were divided according to ...

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      Mentions: Korea University
    14. Optical coherence tomography angiography for the detection of macular neovascularization—comparison of en face versus cross-sectional view

      Optical coherence tomography angiography for the detection of macular neovascularization—comparison of en face versus cross-sectional view

      Purpose To evaluate sensitivity and specificity of swept source-optical coherence tomography angiography (SS-OCTA) en face images versus cross-sectional OCTA versus a combination of both for the detection of macular neovascularization (MNV). Design Prospective cohort study. Participants Consecutive patients with various chorioretinal diseases and subretinal hyperreflective material (SHRM) and/or pigment epithelial detachment (PED) on OCT possibly corresponding to MNV in at least one eye. Methods 102 eyes of 63 patients with fluorescein angiography (FA), OCT and SS-OCTA performed on the same day were included. FA images, the outer retina to choriocapillaris (ORCC) OCTA en face slab, a manually modified en ...

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    15. Perspectives on diabetic retinopathy from advanced retinal vascular imaging

      Perspectives on diabetic retinopathy from advanced retinal vascular imaging

      Diabetic retinopathy (DR) is a microvascular complication of diabetes and the most common cause of acquired vision loss in adults worldwide. DR is associated with long-term chronic hyperglycaemia and its detrimental effects on the neurovascular structure and function of the retina. Direct imaging of the retinal vasculature and staging of DR has been traditionally based on fundoscopy and fluorescein angiography, which provide only 2D views of the retina, and in the case of fluorescein angiography, requires an invasive dye injection. In contrast, advanced retinal imaging modalities like optical coherence tomography angiography (OCTA) and adaptive optics (AO) are non-invasive and provide ...

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    16. Polarization-sensitive optical coherence tomography monitoring of percutaneous radiofrequency ablation in left atrium of living swine

      Polarization-sensitive optical coherence tomography monitoring of percutaneous radiofrequency ablation in left atrium of living swine

      Radiofrequency ablation (RFA) is commonly used to treat atrial fibrillation (AF). However, the outcome is often compromised due to the lack of direct real-time feedback to assess lesion transmurality. In this work, we evaluated the ability of polarization-sensitive optical coherence tomography (PSOCT) to measure cardiac wall thickness and assess RF lesion transmurality during left atrium (LA) RFA procedures. Quantitative transmural lesion criteria using PSOCT images were determined ex vivo using an integrated PSOCT-RFA catheter and fresh swine hearts. LA wall thickness of living swine was measured with PSOCT and validated with a micrometer after harvesting the heart. A total of ...

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    17. Morphological change of the posterior pole following the horizontal strabismus surgery with swept source optical coherence tomography

      Morphological change of the posterior pole following the horizontal strabismus surgery with swept source optical coherence tomography

      Extraocular muscle movement during strabismus surgery causes changes in eyeball shape. Because extraocular muscle insertion is in front of the equator, it is thought that changes due to strabismus surgery mainly occur in the anterior segment. However, changes in the posterior segment of eye may also occur, which may also result in changes in refractive error after strabismus surgery. Using a 3-dimensional reconstruction technique (en face imaging) of the swept source optical coherence tomography, we determined and quantitatively measured the posterior polar change. The deepest interface between Bruch's membrane and the choroid could be identified as the deepest point ...

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    18. Long-term repeatability of peripapillary optical coherence tomography angiography measurements in healthy eyes

      Long-term repeatability of peripapillary optical coherence tomography angiography measurements in healthy eyes

      This is a prospective observational study to establish the short- and long-term repeatability of measurements of peripapillary optical coherence tomography angiography (OCTA) parameters in healthy eyes and identify factors affecting long-term repeatability. We enrolled 84 healthy eyes. Participants with a history of any ophthalmic disease (except high myopia) or intraocular surgery were excluded from the study. An experienced examiner performed OCTA using disc-centered 6 × 6 mm scans. All examinations were conducted twice at 5-min intervals at the initial visit and repeated at least 6 months later. For short-term repeatability, the coefficient of variation (CV) was 2.94-4.22% and the ...

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    19. Macular thickness varies with age-related macular degeneration genetic risk variants in the UK Biobank cohort

      Macular thickness varies with age-related macular degeneration genetic risk variants in the UK Biobank cohort

      To evaluate the influence AMD risk genomic variants have on macular thickness in the normal population. UK Biobank participants with no significant ocular history were included using the UK Biobank Resource (project 2112). Spectral-domain optical coherence tomography (SD-OCT) images were taken and segmented to define retinal layers. The influence of AMD risk single-nucleotide polymorphisms (SNP) on retinal layer thickness was analysed. AMD risk associated SNPs were strongly associated with outer-retinal layer thickness. The inner-segment outer segment (ISOS)-retinal pigment epithelium (RPE) thickness measurement, representing photoreceptor outer segments was most significantly associated with the cumulative polygenic risk score, composed of 33 ...

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    20. Semi-automated quantitative analysis of the middle limiting membrane in tubercular serpiginous-like choroiditis using swept-source optical coherence tomography

      Semi-automated quantitative analysis of the middle limiting membrane in tubercular serpiginous-like choroiditis using swept-source optical coherence tomography

      o analyze the longitudinal changes in the outer plexiform layer (OPL) in patients with tubercular serpiginous-like choroiditis (TB SLC) and compare it to the healthy control population. Clinical and imaging data of subjects with TB SLC (minimum 6-month follow-up) and healthy control subjects were reviewed. Optical coherence tomography (OCT) imaging obtained using swept-source device (DRI Triton, Topcon, Japan) from three visits (baseline, 3 months, and 6 months) were analyzed. Three OCT scans were chosen-one passing through the center of the fovea, one line above, and one line below. After random indexing to anonymize the images, they were pre-processed and fed ...

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    21. Differentiating features of OCT angiography in diabetic macular edema

      Differentiating features of OCT angiography in diabetic macular edema

      The purpose of current study was to evaluate different optical coherence tomography angiography (OCTA) metrics in eyes with diabetic retinopathy with and without diabetic macular edema (DME). In this retrospective study, macular OCTA images of eyes with non-proliferative or proliferative diabetic retinopathy were evaluated. Vascular density, vascular complexity and non-perfusion densities were compared between eyes with and without DME. One-hundred-thirty-eight eyes of 92 diabetic patients including 49 eyes with DME were included. In multivariate analysis, the presence of DME was positively associated with geometric perfusion deficit (GPD) in superficial capillary plexus (SCP), capillary non-perfusion (CNP) of SCP, and GPD in ...

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    22. Longitudinal changes in complete avascular area assessed using anterior segmental optical coherence tomography angiography in filtering trabeculectomy bleb

      Longitudinal changes in complete avascular area assessed using anterior segmental optical coherence tomography angiography in filtering trabeculectomy bleb

      Optical coherence tomography angiography (OCTA) is a new technique for non-invasive imaging of blood vessels, allowing combined evaluation of both deep and surface vessels. The purpose of this study was to evaluate the post-trabeculectomy longitudinal changes in complete avascular area (CAA) of filtering blebs using anterior segment (AS-) OCTA and their association with surgical outcomes. This study included 57 eyes of 53 patients who had undergone trabeculectomy with mitomycin C. AS-OCTA images of filtering bleb were acquired at 3 and 6 months after trabeculectomy, and at 1 month in possible cases. CAAs, regions where complete blood flow was not depicted ...

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    23. Circular functional analysis of OCT data for precise identification of structural phenotypes in the eye

      Circular functional analysis of OCT data for precise identification of structural phenotypes in the eye

      Progressive optic neuropathies such as glaucoma are major causes of blindness globally. Multiple sources of subjectivity and analytical challenges are often encountered by clinicians in the process of early diagnosis and clinical management of these diseases. In glaucoma, the structural damage is often characterized by neuroretinal rim (NRR) thinning of the optic nerve head, and other clinical parameters. Baseline structural heterogeneity in the eyes can play a key role in the progression of optic neuropathies, and present challenges to clinical decision-making. We generated a dataset of Optical Coherence Tomography (OCT) based high-resolution circular measurements on NRR phenotypes, along with other ...

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    24. A deep learning model for identifying diabetic retinopathy using optical coherence tomography angiography

      A deep learning model for identifying diabetic retinopathy using optical coherence tomography angiography

      As the prevalence of diabetes increases, millions of people need to be screened for diabetic retinopathy (DR). Remarkable advances in technology have made it possible to use artificial intelligence to screen DR from retinal images with high accuracy and reliability, resulting in reducing human labor by processing large amounts of data in a shorter time. We developed a fully automated classification algorithm to diagnose DR and identify referable status using optical coherence tomography angiography (OCTA) images with convolutional neural network (CNN) model and verified its feasibility by comparing its performance with that of conventional machine learning model. Ground truths for ...

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