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    1. Wide-Field Swept-Source Optical Coherence Tomography Analysis of Interocular Symmetry of Choroidal Thickness in Healthy Young Individuals

      Wide-Field Swept-Source Optical Coherence Tomography Analysis of Interocular Symmetry of Choroidal Thickness in Healthy Young Individuals

      Purpose: The purpose of this paper was to study the bilateral choroidal thickness (CT) symmetry and differences in healthy individuals using wide-field swept-source optical coherence tomography (SS-OCT). Methods: All participants underwent a wide-field 16-mm 1-line scan using SS-OCT. CTs were measured at the following 12 points: 3 points at 900 µm, 1800 µm, and 2700 µm away from the nasal optic disc margin (nasal peripapillary area), 1 point at the subfovea, 6 points at 900 µm, 1800 µm, and 2700 µm away from the subfovea to the nasal and temporal areas (macular area), and 2 peripheral points at 2700 and ...

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    2. Follow-Up of Nonarteritic Anterior Ischemic Optic Neuropathy With Optical Coherence Tomography Angiography

      Follow-Up of Nonarteritic Anterior Ischemic Optic Neuropathy With Optical Coherence Tomography Angiography

      Purpose : The purpose of this study was to describe capillary changes in patients with nonarteritic anterior ischemic optic neuropathy (NAION) using optical coherence tomography-angiography (OCT-A) and correlate the results with best corrected visual acuity (BCVA), visual field, OCT retinal nerve fiber layer (RNFL), and combined thickness of ganglion cell and inner plexiform layers (GCIPL) thicknesses. Methods : We enrolled 22 eyes with acute NAION and 30 normal control (NC) subjects in this study. Whole en face image vessel density (WiVD) was measured in the radial peripapillary capillary plexus (RPC), superficial capillary plexus (SCP), and deep vascular complex (DVC) using OCT-A. The ...

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    3. Longitudinal Changes in Macular Optical Coherence Tomography Angiography Metrics in Primary Open-Angle Glaucoma With High Myopia: A Prospective Study

      Longitudinal Changes in Macular Optical Coherence Tomography Angiography Metrics in Primary Open-Angle Glaucoma With High Myopia: A Prospective Study

      Purpose : To characterize longitudinal changes in macular microvasculature as quantified from optical coherence tomography angiography (OCTA) metrics in primary open-angle glaucoma (POAG) eyes with and without high myopia. Methods : In total, 63 and 61 POAG eyes with and without high myopia, respectively, underwent swept-source OCTA imaging in at least four follow-up visits at an ophthalmic center, with a scanning protocol of 3- × 3-mm centered at the fovea. The foveal avascular zone (FAZ) area, FAZ circularity, and vessel density (VD) in both the superficial (SCP) and deep capillary plexuses (DCP) were measured. The rate of change in macular OCTA metrics over ...

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    4. The Macular Choriocapillaris Flow in Glaucoma and Within-Day Fluctuations: An Optical Coherence Tomography Angiography Study

      The Macular Choriocapillaris Flow in Glaucoma and Within-Day Fluctuations: An Optical Coherence Tomography Angiography Study

      Purpose: To assess quantitatively the choriocapillaris (CC) perfusion area in the macular area of healthy eyes, eyes with primary open-angle glaucoma, and eyes with ocular hypertension using optical coherence tomography angiography (OCTA). Methods: A consecutive series of healthy individuals and patients with glaucoma and ocular hypertension were recruited prospectively in this single-center, cross-sectional study based in Milan, Italy. OCTA was performed in the morning and evening, along with a complete ophthalmologic examination. Macular superficial capillary plexus vessel density (SCP-VD) and the thicknesses of the retina and ganglion cell complex (GCC), as well as their fluctuations, were investigated. Results: Thirty-nine eyes ...

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    5. Diabetic Macular Ischemia: Influence of Optical Coherence Tomography Angiography Parameters on Changes in Functional Outcomes Over One Year

      Diabetic Macular Ischemia: Influence of Optical Coherence Tomography Angiography Parameters on Changes in Functional Outcomes Over One Year

      Purpose : To prospectively evaluate whether diabetic macular ischemia detected with coherence tomography angiography (OCTA) is associated with change in functional outcomes over a period of one year. Methods : This is a one-year prospective, observational study that included 56 eyes with varying levels of diabetic retinopathy. All participants underwent best corrected visual acuity evaluation, swept-source OCTA and microperimetry at baseline and repeated at one year. Parafoveal vessel densities (VD) and foveal avascular zone (FAZ) areas were generated from OCTA in the superficial and deep vascular plexuses. The influence of baseline and change in OCTA parameters on change in visual acuity and ...

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    6. Assessment of Choroidal Vascularity and Choriocapillaris Blood Perfusion in Anisomyopic Adults by SS-OCT/OCTA

      Assessment of Choroidal Vascularity and Choriocapillaris Blood Perfusion in Anisomyopic Adults by SS-OCT/OCTA

      Purpose: To explore the association of choroidal vascularity and choriocapillaris blood perfusion with myopic severity in anisomyopes. Methods: Refractive error, axial length (AL), and other biometric parameters were measured in 34 anisomyopic young adults. Macular choroidal thickness (ChT) and choroidal vascularity, including total choroidal area (TCA), luminal area (LA), stromal area (SA), and choroidal vascularity index (CVI), were determined from swept-source optical coherence tomography (SS-OCT) vertical and horizontal B-scans. The percentage of choriocapillaris flow voids (FV%) was obtained from en face SS-OCT-angiography. Results: The spherical equivalent refraction (SER) was -3.35 ± 1.25 diopters in the more myopic eyes and ...

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    7. Focal Structure-Function Relationships in Primary Open-Angle Glaucoma Using OCT and OCT-A Measurements

      Focal Structure-Function Relationships in Primary Open-Angle Glaucoma Using OCT and OCT-A Measurements

      Purpose: To evaluate the focal structure-function associations among visual field (VF) loss, optical coherence tomography angiography (OCT-A) vascular measurements, and optical coherence tomography (OCT) structural measurements in glaucoma. Methods: In this cross-sectional study, subjects underwent standard automated perimetry, OCT-based nerve fiber thickness measurements, and OCT-A imaging. Mappings of focal VF test locations with OCT and OCT-A measurements were defined using anatomically adjusted nerve fiber trajectories and were studied using multivariate mixed-effects analysis. Segmented regression analysis was used to determine the presence of breakpoints in the structure-function associations. Results: The study included 119 eyes from 86 Chinese subjects with primary open-angle ...

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    8. Reduced Pulsatile Trabecular Meshwork Motion in Eyes With Primary Open Angle Glaucoma Using Phase-Sensitive Optical Coherence Tomography

      Reduced Pulsatile Trabecular Meshwork Motion in Eyes With Primary Open Angle Glaucoma Using Phase-Sensitive Optical Coherence Tomography

      Purpose: The purpose of this study was to investigate the difference in pulsatile trabecular meshwork (TM) motion between normal and eyes with POAG using phase-sensitive optical coherence tomography (PhS-OCT). Methods: In this cross-sectional study, eight healthy subjects (16 eyes) and nine patients with POAG (18 eyes) were enrolled. A laboratory-based prototype PhS-OCT system was used to measure pulsatile TM motion. PhS-OCT images were analyzed to obtain parameters of pulsatile TM motion (i.e. maximum velocity [MV] and cumulative displacement [CDisp]). Outflow facility and ocular pulse amplitude were measured using pneumotonography. Detection sensitivity was compared among various parameters by calculating the ...

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    9. Dynamic Optical Coherence Elastography of the Anterior Eye: Understanding the Biomechanics of the Limbus

      Dynamic Optical Coherence Elastography of the Anterior Eye: Understanding the Biomechanics of the Limbus

      Purpose : Currently, the biomechanical properties of the corneo-scleral limbus when the eye-globe deforms are largely unknown. The purpose of this study is to evaluate changes in elasticity of the cornea, sclera, and limbus when subjected to different intraocular pressures (IOP) using wave-based optical coherence elastography (OCE). Special attention was given to the elasticity changes of the limbal region with respect to the elasticity variations in the neighboring corneal and scleral regions. Methods : Continuous harmonic elastic waves (800 Hz) were mechanically induced in the sclera near the corneo-sclera limbus of in situ porcine eye-globes ( n = 8). Wave propagation was imaged using ...

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    10. Retinal Neurovascular Impairment in Patients with Essential Hypertension: An Optical Coherence Tomography Angiography Study

      Retinal Neurovascular Impairment in Patients with Essential Hypertension: An Optical Coherence Tomography Angiography Study

      Purpose : To investigate retinal neurovascular structural changes in patients with essential hypertension. Methods : This observational cross-sectional study consisted of 199 right eyes from 169 nondiabetic essential hypertensive patients, divided into groups as follows: group A, 113 patients with hypertensive retinopathy (HTNR); group B, 56 patients without HTNR; and a control group of 30 healthy subjects. Peripapillary retinal nerve fiber layer (RNFL), radial peripapillary segmented (RPC), ganglion cell–inner plexiform layer (GC-IPL), and superficial (SVP) and deep (DVP) vascular plexus density at the macula (6 × 6 mm 2 ) were measured by optical coherence tomography angiography (OCTA). Results : DVP density was significantly ...

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    11. Ultrahigh Resolution Spectral Domain Optical Coherence Tomography for the Assessment of Micro-Structural Changes in Central Serous Chorioretinopathy: A Pilot Study.

      Ultrahigh Resolution Spectral Domain Optical Coherence Tomography for the Assessment of Micro-Structural Changes in Central Serous Chorioretinopathy: A Pilot Study.

      Purpose : In central serous chorioretinopathy (CSCR), choroidal hyperpermeability associated with retinal pigment epithelium (RPE) impairment causes a leakage of fluid from the choroid into the subretinal space, with potential damage to the photoreceptors. We hypothesize that ultrahigh-resolution spectral domain optical coherence tomography (UHR SD-OCT) will enable more detailed assessment of structural changes in this condition. Methods : Patients in all stages of CSCR (acute, chronic and post-resolution) were imaged using an UHR SD-OCT prototype, with an 850 nm center wavelength and an axial resolution of ~2.7 µm in tissue at a 128kHz A-scan rate. Volumetric cube scans and high-density (HD ...

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    12. Evaluating the long-term effects of anti-vascular endothelial growth factor therapy on choroidal neovascularization in age-related macular degeneration using optical coherence tomography angiography

      Evaluating the long-term effects of anti-vascular endothelial growth factor therapy on choroidal neovascularization in age-related macular degeneration using optical coherence tomography angiography

      Purpose : Optical coherence tomography angiography (OCTA) allows for precise, non-invasive monitoring of changes to choroidal neovascularization (CNV) structure over time. The short-term effects of anti-vascular endothelial growth factor (anti-VEGF) treatment on CNV morphology is well described, but long-term studies on morphologic changes and correlation of such to the type of CNV have not been conducted. This study aims to determine if different types of CNVs in neovascular AMD (nAMD) behave differently with anti-VEGF treatment as visualized on OCTA. Methods : AMD Patients with treatment naive type 1, type 2, and type 3 CNVs were retrospectively screened for baseline and follow-up OCTA ...

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    13. Bringing Deep Learning Models to the Data: An Application in Recognizing Intra-Retinal Fluid on Optical Coherence Tomography (OCT) Images

      Bringing Deep Learning Models to the Data: An Application in Recognizing Intra-Retinal Fluid on Optical Coherence Tomography (OCT) Images

      Purpose : Amidst intense interest in deep learning in medicine, concerns regarding data privacy, security, and sharing are of increasing importance. A model-to-data approach, in which the model itself is transferred rather than data, can circumvent many of these challenges, but has not been previously tested in ophthalmology. The objective of our study was to determine whether a model-to-data deep learning approach (i.e. validation of the algorithm without any data transfer) can be successfully applied for the first time to deep learning in ophthalmology. Methods : This is a cross sectional study in which a deep learning algorithm model developed at ...

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    14. A machine learning method for optical coherence tomography scan quality assessment

      A machine learning method for optical coherence tomography scan quality assessment

      Purpose : The reliability of automated analysis of optical coherence tomography (OCT) scans depends on the scan quality. Quality indicators in commercial instruments only provide an overall score and do not provide localized information. Here we demonstrated a quality map using a semi-supervised machine learning technique which can aid with identifying local areas of poor quality. Methods : Our method first computes a set of feature maps using signal strength, signal-to-noise ratio (SNR), and contrast for individual or a group of neighboring A-scans of 580 6x6x2mm OCT volumes with good and poor quality (Fig 1A shows one volume). It then combines the ...

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    15. Clustering Spectral-Domain Optical Coherence Tomography Images using a Deep Variational Auto-encoder

      Clustering Spectral-Domain Optical Coherence Tomography Images using a Deep Variational Auto-encoder

      Purpose : To learn a low-dimensional representation of spectral-domain optical coherence tomography (SD OCT) peripapillary images that can be used to classify images into glaucoma versus healthy eyes. Methods : The study included 23,992 Spectralis SD OCT images from 1,336 eyes, of which 30% were healthy and the remaining were glaucoma or glaucoma suspects. The definition of groups was based on visual fields and inspection of the optic nerve. In order to learn a low-dimensional representation of the high-dimensional SD OCT images a variational auto-encoder (VAE) was used, an unsupervised deep learning technique. The encoder and decoder of the VAE ...

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      Mentions: Duke University
    16. Improved Denoising of Optical Coherence Tomography via Repeated Acquisitions and Unsupervised Deep Learning

      Improved Denoising of Optical Coherence Tomography via Repeated Acquisitions and Unsupervised Deep Learning

      Purpose : Optical Coherence Tomography (OCT) is widely used, yet its interpretation is confounded by strong speckle noise. Previous denoising methods make strong assumptions on noise characteristics and struggle to retain fine structure. We present a data-driven registration and denoising method which vastly improves image fidelity while requiring only repeated noisy acquisitions of individual subjects. Methods : Noise2Noise is an unsupervised denoising approach for repeatedly acquired noisy images (Lehtinen, ICML , 2018). By training a convolutional neural network on noisy image pairs with zero-mean noise, the mean of the clean image distribution is learned. However, repeats are assumed to vary only in noise ...

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    17. Imaging artifacts in widefield optical coherence tomography angiography in patients with retinitis pigmentosa

      Imaging artifacts in widefield optical coherence tomography angiography in patients with retinitis pigmentosa

      Purpose : Optical coherence tomography angiography (OCTA) provides high-resolution images of retinal vasculature whereby vessel density (VD) can be used as an outcome marker. VD is diminished in patients with retinitis pigmentosa (RP) but its quantification can be confounded by imaging artifacts. In this retrospective study, we investigate artifacts that may affect the clinical application of widefield OCTA (WF-OCTA) in patients with RP. Methods : University of Kentucky IRB (#48463) approved retrospective analysis of WF-OCTA images from 33 subjects with a diagnosis of RP and 12x12mm OCTA imaging (Plex Elite 9000, Zeiss, Dublin, CA). Images form the eye with higher signal strength ...

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    18. Functional optical coherence tomography of photoreceptor outer and inner segments in living eye.

      Functional optical coherence tomography of photoreceptor outer and inner segments in living eye.

      Purpose : This study is to investigate stimulus-evoked intrinsic optical signal (IOS) changes in photoreceptor outer segment (OS) and inner segment (IS), and thus to demonstrate the potential of functional IOS imaging of phototransduction and metabolic integrity of retinal photoreceptor. Methods : A custom-designed optical coherence tomography (OCT) was used for in vivo imaging of transient IOS changes in the retina of wild-type mice (C57BL/6J). A near-infrared superluminescent diode (SLD) was used as the light source for OCT imaging, and a visible light-emitting diode (LED) was employed for retinal stimulation. Depth-resolved IOSs were calculated at individual retina layers, based on the ...

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    19. Effects of water drinking test on ocular blood flow using optical coherence tomography angiography

      Effects of water drinking test on ocular blood flow using optical coherence tomography angiography

      Purpose : Increased intraocular pressure (IOP) is a major risk factor for the development of glaucoma and its progression. Literature has proposed the water drinking test (WDT) as a practical method to predict the IOP peak of diurnal tension curve. This preliminary study assesses changes in macular and peripapillary vascular microcirculation using optical coherence tomography angiography (OCTA) metrics after WDT in healthy eyes. Methods : Five healthy subjects (age 37±7.9 years) underwent the WDT, which involved drinking a 1-liter water load in 5 minutes after 4 hours of fasting. IOP using non-contact tonometry and OCTA scans from CIRRUS™ 6000 AngioPlex ...

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    20. Impact of retinal dewarping on thickness measurements in widefield optical coherence tomography volumes

      Impact of retinal dewarping on thickness measurements in widefield optical coherence tomography volumes

      Purpose : Recent developments in optical coherence tomography (OCT) imaging have demonstrated widefield imaging up to 90° field of view (FOV). The purpose of this study is to develop a two-dimensional dewarping method for retinal OCT volumes and to evaluate the impact of retinal dewarping on thickness measurements. Methods : The method developed by Steidle (Biophotonics: Photonic Solutions for Better Health Care VI, 2018) was expanded to dewarp widefield OCT volumes. A digital model dataset of two retinal layers with a thickness of 200 µm was created. We compared the traditional thickness measurement along the OCT A-scan with a thickness measurement that ...

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    21. 3D Image Registration Based Atlas for Large Field of View Human Eye Optical Coherence Tomography

      3D Image Registration Based Atlas for Large Field of View Human Eye Optical Coherence Tomography

      Purpose : Optical coherence tomography (OCT) is a non-invasive imaging modality used for high resolution (10 μ) imaging of ocular tissue. Retinal cell layers are clearly visible on OCT providing a means for quantitative and topographical analysis. Medical atlases are important tools for detecting abnormal structural and anatomical tissue alterations, relative to a standardized normal. They can also serve as a reference for registration of individual images for deformation-based analysis. The purpose of the current study is to present a method for generating an atlas of the human eye using large field of view 3D OCT image volumes. Methods : Imaging was performed ...

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    22. Multi-label multi-task macular Optical Coherence Tomography (OCT) scans classification system

      Multi-label multi-task macular Optical Coherence Tomography (OCT) scans classification system

      Purpose : Macular OCT cubes generally contain multiple B-scans, making the clinical decision time-consuming and tedious. For an effective and fast clinical decision, it is essential to develop an automatic algorithm that identifies the anomalous cube and B-scans, the pathologies present within the B-scans, and overall disease. We present an algorithm that predicts whether the B-scan contains abnormality or not along with the presence of multiple pathologies and also the cube level abnormalities. Methods : The multi-label multi-task algorithm is developed in two phases using 1485 OCT macular cubes (75,264 B-scans) of 328 subjects (132 normal, 196 with macular pathologies) acquired ...

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    23. Ultrahigh-Resolution Optical Coherence Tomography Investigation of Age-Related Changes in the Photoreceptors, Retinal Pigment Epithelium and Bruch’s Membrane

      Ultrahigh-Resolution Optical Coherence Tomography Investigation of Age-Related Changes in the Photoreceptors, Retinal Pigment Epithelium and Bruch’s Membrane

      Purpose : Aging is the biggest risk factor for age-related macular degeneration (AMD). Previous histological and ultrastructural studies have suggested that photoreceptors (PR), retinal pigment epithelium (RPE), and Bruch’s membrane (BM) undergo changes with aging and in AMD. A new high-speed, ultrahigh-resolution optical coherence tomography (UHR OCT) prototype instrument with depth tracking and software motion correction was used to investigate PR/RPE/BM alterations in normal aging and early AMD. Methods : We developed a high-speed UHR OCT instrument with 2.7 µm axial resolution and 128 kHz A-scan rate. A galvanometer scanner actuates the OCT reference arm to match the ...

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    24. Detection of Venous Loops in Diabetic Retinopathy using Widefield Swept-Source Optical Coherence Tomography Angiography

      Detection of Venous Loops in Diabetic Retinopathy using Widefield Swept-Source Optical Coherence Tomography Angiography

      Purpose : Retinal venous loops (RVL) are rare manifestations of diabetic retinopathy (DR) usually identified by color fundus photography. The prevalence and its predictive value reported in the literature may be underestimated due to the limitations of detection techniques. This study investigated the prevalence of RVL and their associated microvascular changes using widefield swept-source optical coherence tomography angiography (WF SS-OCTA). Methods : In this retrospective, observational study at Mass Eye and Ear from December 2018 to December 2019, diabetic patients with proliferative diabetic retinopathy (PDR), non-proliferative diabetic retinopathy (NPDR) and without DR were included. All patients were imaged with a WF SS-OCTA ...

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