1. Articles from srinivas r. sadda

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    1. Evaluation of the inner choroid using OCT angiography

      Evaluation of the inner choroid using OCT angiography

      The advent of optical coherence tomography angiography (OCTA) has allowed a qualitative and quantitative analysis of the retinal vasculature and the choriocapillaris. With the use of OCTA, several studies evaluated the changes in the choriocapillaris showing how this vascular structure plays a significant role in the pathogenesis of different conditions. This article reviews the current methods of analysis of the choriocapillaris and the relevant findings in different chorioretinal diseases.

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    2. Comparison and Repeatability of High Resolution and High Speed Scans from Spectralis Optical Coherence Tomography Angiography

      Comparison and Repeatability of High Resolution and High Speed Scans from Spectralis Optical Coherence Tomography Angiography

      Purpose : The purpose of this study was to evaluate and compare the repeatability of optical coherence tomography angiography (OCTA) derived retinal vascular quantitative metrics using high resolution (HR) versus high speed (HS) acquisition modes. Methods : Macular 4.4 × 2.9-mm OCTA images from normal, healthy volunteers were captured using both HR (768 A-scans × 256 B-scans) and HS (384 A-scans × 256 B-scans) acquisition protocols. Vessel density and vessel length density of the superficial capillary plexus and deep capillary plexus, as well as choriocapillaris flow deficit were computed. In a subset of eyes, the OCTA scans were repeated twice 2 days later ...

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    3. Impact of Scan Tilt on Quantitative Assessments Using Optical Coherence Tomography Angiography

      Impact of Scan Tilt on Quantitative Assessments Using Optical Coherence Tomography Angiography

      Purpose : To investigate the impact of scan tilt on quantitative assessments using swept-source optical coherence tomography angiography (SS-OCTA) in healthy participants. Methods : Healthy participants were imaged with a SS-OCTA system (PLEX Elite 9000; Carl Zeiss Meditec, Inc, Dublin, CA). After a standard scan was obtained, tilted scans were obtained by moving the optical coherence tomography beam entrance position horizontally. The tilting angle was measured from the B-scan image, and the flattest (horizontal) and the most tilted images were selected for comparative analysis. Foveal avascular zone (FAZ) area, vessel density (VD), and vessel length density (VLD) from the superficial and deep ...

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    4. Concerns about the interpretation of OCT and fundus findings in COVID-19 patients in recent Lancet publication

      Concerns about the interpretation of OCT and fundus findings in COVID-19 patients in recent Lancet publication

      We read with great interest the correspondence in Lancet by Marinho et al. [ 1 ] describing purported retinal manifestations of coronavirus disease (COVID-19). While there is great interest to understand potential ocular complications of COVID-19 during this pandemic, we have some concerns regarding the interpretation of the fundus and optical coherence tomography (OCT) findings. Marinho et al. examined 12 COVID-19 patients (all confirmed by PCR or antibody testing) with typical systemic disease but no visual symptoms. The reported cohort was relatively young (25–69 years; no mean or median provided) without severe systemic disease, although 2 were hospitalized. Eleven of the ...

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    5. Optical coherence tomography angiography for detection of macular neovascularization associated with atrophy in age-related macular degeneration

      Optical coherence tomography angiography for detection of macular neovascularization associated with atrophy in age-related macular degeneration

      Purpose To evaluate the ability of optical coherence tomography angiography (OCTA) to detect macular neovascularization (MNV) in eyes with atrophy compared with fluorescein angiography (FA), indocyanine green angiography (ICGA), and optical coherence tomography (OCT). Methods In this prospective study, eyes with MNV and atrophy (termed macular atrophy or MA) secondary to age-related macular degeneration (AMD), and AMD eyes with geographic atrophy (GA) without MNV underwent multimodal imaging with FA, ICGA, structural OCT, and OCTA. The presence of MNV was determined using all imaging modalities by senior retina specialists and was considered the gold standard reference. Each individual imaging modality was ...

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    6. Association of Intravitreal Aflibercept With Optical Coherence Tomography Angiography Vessel Density in Patients With Proliferative Diabetic Retinopathy: A Secondary Analysis of a Randomized Clinical Trial

      Association of Intravitreal Aflibercept With Optical Coherence Tomography Angiography Vessel Density in Patients With Proliferative Diabetic Retinopathy: A Secondary Analysis of a Randomized Clinical Trial

      Importance Although previous studies have evaluated the association between anti–vascular endothelial growth factor therapy and macular vessel density, they were confounded by the presence of macular edema, which may be associated with artifacts and segmentation errors in optical coherence tomography angiography (OCTA). Objective To evaluate the association of intravitreal aflibercept with changes in macular vascular density using OCTA in patients with proliferative diabetic retinopathy without diabetic macular edema. Design, Setting, and Participants This post hoc analysis of a randomized clinical trial used data on 40 eyes of 40 patients with proliferative diabetic retinopathy without diabetic macular edema who were ...

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    7. Automated Retinal Layer Segmentation Using Graph-based Algorithm Incorporating Deep-learning-derived Information

      Automated Retinal Layer Segmentation Using Graph-based Algorithm Incorporating Deep-learning-derived Information

      Regular drusen, an accumulation of material below the retinal pigment epithelium (RPE), have long been established as a hallmark early feature of nonneovascular age-related macular degeneration (AMD). Advances in imaging have expanded the phenotype of AMD to include another extracellular deposit, reticular pseudodrusen (RPD) (also termed subretinal drusenoid deposits, SDD), which are located above the RPE. We developed an approach to automatically segment retinal layers associated with regular drusen and RPD in spectral domain (SD) optical coherence tomography (OCT) images. More specifically, a shortest-path algorithm enhanced with probability maps generated through a fully convolutional neural network was used to segment ...

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    8. Subtype-differentiated impacts of subretinal drusenoid deposits on photoreceptors revealed by adaptive optics scanning laser ophthalmoscopy

      Subtype-differentiated impacts of subretinal drusenoid deposits on photoreceptors revealed by adaptive optics scanning laser ophthalmoscopy

      Purpose To examine the structure of photoreceptors surrounding two subtypes of subretinal drusenoid deposits (SDD), namely, dot and ribbon SDD, using multimodal imaging including adaptive optics scanning laser ophthalmoscopy (AOSLO) and spectral-domain optical coherence tomography (SD-OCT). Methods Twenty-six eyes of 13 patients with age-related macular degeneration (AMD) and SDD and 16 eyes of 8 subjects in normal chorioretinal health were studied. SDD presence, stage, and subtype were determined using color fundus photographs, infrared reflectance, autofluorescence imaging, and SD-OCT. SDD and surrounding photoreceptors were imaged using AOSLO. The structure of cone photoreceptors and SDD was examined at the baseline and at ...

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    9. Thresholding strategies to measure vessel density by optical coherence tomography angiography

      Thresholding strategies to measure vessel density by optical coherence tomography angiography

      Objective A variety of binarization strategies have been used to measure vessel density by optical coherence tomography angiography (OCT-A), but it is uncertain if they produce similar results. The purpose of the study was to evaluate the impact of different thresholding methods and contrast and brightness adjustment on OCT-A vessel density metrics. Design Observational, cross-sectional case series. Participants Consecutive healthy volunteers. Methods Healthy volunteers underwent fovea-centred 3 mm × 3 mm OCT-A scans using PlexElite 9000. Images of the superficial vascular plexus were generated using the instrument’s automated segmentation. Images were thresholded with 5 different threshold tools in ImageJ (Default ...

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    10. Optimizing the Repeatability of Choriocapillaris Flow Deficit Measurement from Optical Coherence Tomography Angiography

      Optimizing the Repeatability of Choriocapillaris Flow Deficit Measurement from Optical Coherence Tomography Angiography

      Purpose To evaluate impact of processing technique and slab selection on the repeatability of choriocapillaris (CC) flow deficit (FD) measurements as assessed using optical coherence tomography angiography (OCTA) Design: prospective, cross-sectional study Methods Healthy subjects were imaged with four consecutive 3x3mm OCTA using a swept source OCT (PLEX elite 9000, Carl Zeiss Meditec, Dublin, CA). OCTA images were generated using the Max projection, and three 10 μm-thick slabs starting 11, 21 and 31 μm posterior to the automatically segmented retinal pigment epithelium (RPE) band. The resultant images were binarized using Phansalkar’s method with a 43.94 μm radius and ...

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    11. Effect of image averaging on optical coherence tomography angiography data in eyes with branch retinal vein occlusion

      Effect of image averaging on optical coherence tomography angiography data in eyes with branch retinal vein occlusion

      Purpose To investigate the effect of image averaging on qualitative and quantitative assessments of optical coherence tomography angiography (OCTA) images from eyes of patients with branch retinal vein occlusion (BRVO). Methods Macular OCTA images of 33 eyes of 33 patients with BRVO were obtained using the HS100 HR-SD-OCT system (Canon, Inc.). For each eye, five OCTA cube scans were obtained with a 3 × 3 mm scan protocol, and the data were averaged and compounded into a single high image quality cube data using built-in software. Pre- and post-averaging images were compared qualitatively and quantitatively in superficial capillary plexus (SCP) and ...

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    12. Reproducibility and agreement of four anterior segment-optical coherence tomography devices for anterior chamber angle measurements

      Reproducibility and agreement of four anterior segment-optical coherence tomography devices for anterior chamber angle measurements

      Purpose To compare the reproducibility and agreement of anterior chamber angle (ACA) parameters and metrics obtained by four different anterior segment-optical coherence tomography (AS-OCT) devices. Methods In this prospective study, 30 eyes from 15 normal subjects underwent anterior segment angle scanning using the Spectralis, Cirrus, and Optovue spectral domain optical coherence tomography (SD-OCT), as well as the Visante time-domain optical coherence tomography (TD-OCT). For each eye, the scan line was performed perpendicularly on the inferior (270°) angle, and the inferior ACA image was acquired 2 times. Inter-instrument and intra-instrument, as well as inter-observer and intra-observer reproducibility of anterior chamber angle ...

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    13. Quantitative assessment of the retinal microvasculature and choriocapillaris in myopic patients using swept-source optical coherence tomography angiography

      Quantitative assessment of the retinal microvasculature and choriocapillaris in myopic patients using swept-source optical coherence tomography angiography

      Purpose To study the retinal capillary microvasculature and the choriocapillaris (CC) in myopic eyes using swept-source optical coherence tomography angiography (SS-OCTA). Methods Patients with high myopia (≥ − 6D; axial length ≥ 26.5 mm), moderate myopia (≥ − 3D, < − 6D), and age-matched healthy subjects presenting to the Shanghai General Hospital and Doheny-UCLA Eye Centers were enrolled in this prospective, multicenter study. Any subjects with evidence of macular abnormalities suggestive of pathologic myopia were excluded. SS-OCTA at both sites was performed using a Zeiss PLEX Elite instrument with a 6 × 6 mm scan pattern centered on the fovea. Two repeated volume scans were acquired for ...

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    14. Appearance of cysts and capillary non perfusion areas in diabetic macular edema using two different OCTA devices

      Appearance of cysts and capillary non perfusion areas in diabetic macular edema using two different OCTA devices

      The aim of this paper was to distinguish the appearance of cysts and non-perfusion areas (NPAs) in diabetic macular edema (DME) using two different Optical Coherence Tomography Angiography (OCTA) devices. In this study, patients underwent OCTA using the AngioVue XR Avanti Spectral Domain (SD) OCTA and the PLEX Elite 9000 Swept-Source (SS) OCTA. Foveal and extrafoveal regions of interest (ROI), defined as any area with an altered flow signal comparing to the surrounding retina, were selected in superficial and deep capillary plexus (SCP and DCP). ROI reflectivity were classified as hypo-reflective or hyper-reflective. Foveal ROI were analyzed to detect suspended ...

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    15. Impact of slab selection on quantification of choriocapillaris flow deficits by optical coherence tomography angiography

      Impact of slab selection on quantification of choriocapillaris flow deficits by optical coherence tomography angiography

      Purpose To assess the impact of slab selection on quantitative measurements of choriocapillaris (CC) flow deficits (FDs) using optical coherence tomography angiography (OCTA). Design Cross-sectional study Methods Using a swept-source OCTA device, en face slabs to isolate the CC were first generated using the manufacturer’s default setting: a 20 μm-thick slab starting 29 μm posterior to the centerline of the automatically segmented retinal pigment epithelium (RPE) band. The inner and or outer borders were then adjusted by 2 μm increments to generate CC slabs with a range of offsets relative to the center of the RPE band. FDs of ...

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    16. Retinal Vascular Changes During Pregnancy Detected With Optical Coherence Tomography Angiograph

      Retinal Vascular Changes During Pregnancy Detected With Optical Coherence Tomography Angiograph

      Purpose : To evaluate retinal vascular status during pregnancy by using optical coherence tomography angiography (OCTA). Methods : Women in their third trimester of pregnancy and nonpregnant age-matched women were recruited for this prospective, case-control study. Subjects were imaged with OCTA. Main outcome measures were foveal avascular zone parameters, perfusion density (PD) percentage in the superficial retinal capillary plexus (SCP), PD percentage in the deep retinal capillary plexus (DCP), SCP vessel length density (VLD), DCP-VLD, and choriocapillaris (CC) flow voids (i.e., flow deficits in the CC). Results : Nineteen eyes of 10 pregnant subjects and 44 eyes of 27 nonpregnant control women ...

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    17. Optical coherence tomography risk factors for development of late age related macular degeneration in the fellow eyes of patients enrolled in the HARBOR Study

      Optical coherence tomography risk factors for development of late age related macular degeneration in the fellow eyes of patients enrolled in the HARBOR Study

      Purpose To evaluate the relationship between optical coherence tomography (OCT) features and the progression to late age related macular degeneration (AMD) in the fellow eyes of patients enrolled in the 24-month HARBOR study (NCT00891735) for neovascular AMD. Design post hoc analysis of a phase 3 multicenter, prospective, randomized, double-masked, active treatment-controlled clinical trial. Participants Evaluable subjects (N=501) with macular neovascularization (MNV) secondary to neovascular AMD and early or intermediate AMD in the fellow eye. Methods Volume OCT scans from 501 fellow eyes of 501 patients with MNV were reviewed. Baseline OCT features that were assessed included intraretinal hypereflective foci ...

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    18. Macular Microvascular Networks In Healthy Pediatric Subjects

      Macular Microvascular Networks In Healthy Pediatric Subjects

      Purpose: To report optical coherence tomography angiography ( OCTA ) values in healthy pediatric eyes and to identify factors that may modify these values. Methods: In this prospective observational cross-sectional study, macular OCTA images were acquired from healthy pediatric patients. Main outcome measures were 1) foveal avascular zone (FAZ) area at the level of the superficial retinal capillary plexus (SCP); 2) SCP and deep retinal capillary plexus (DCP) perfusion density (based on the area of vessels); 3) SCP and DCP vessel density (based on a map with vessels of 1-pixel width); and 4) CC perfusion density. Multiple regression analysis was performed to ...

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    19. Pearls and Pitfalls of Optical Coherence Tomography Angiography Imaging: A Review

      Pearls and Pitfalls of Optical Coherence Tomography Angiography Imaging: A Review

      Optical coherence tomography angiography (OCTA) has significantly expanded our knowledge of the ocular vasculature. Furthermore, this imaging modality has been widely adopted to investigate different ocular and systemic diseases. In this review, a discussion of the fundamental principles of OCTA is followed by the application of this imaging modality to study the retinal and choroidal vessels. A proper comprehension of this imaging modality is essential for the interpretation of OCTA imaging applications in retinal and choroidal disorders.

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    20. CORRELATION OF EN FACE OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY AVERAGING VERSUS SINGLE-IMAGE QUANTITATIVE MEASUREMENTS WITH RETINAL VEIN OCCLUSION VISUAL OUTCOMES

      CORRELATION OF EN FACE OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY AVERAGING VERSUS SINGLE-IMAGE QUANTITATIVE MEASUREMENTS WITH RETINAL VEIN OCCLUSION VISUAL OUTCOMES

      Purpose: To demonstrate the effect of averaging multiple en face optical coherence tomography angiography images on the correlation between retinal microvasculature quantitative metrics and best-corrected visual acuity (BCVA) in eyes with retinal vein occlusion . Methods: A cross-sectional cohort with unilateral retinal vein occlusion was imaged in both eyes. Five 3 mm × 3-mm spectral domain optical coherence tomography angiography images were averaged, and quantitative parameters from averaged versus single images were correlated with logMAR BCVA. Regression analyses were performed to correlate quantitative metrics with BCVA. Results: Ten patients (5 male, average age 64.3 years) were included. Among retinal vein occlusion ...

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    21. Impact of segmentation density on spectral domain optical coherence tomography assessment in Stargardt disease

      Impact of segmentation density on spectral domain optical coherence tomography assessment in Stargardt disease

      Purpose Automated spectral domain optical coherence tomography (SD-OCT) segmentation algorithms currently do not perform well in segmenting individual intraretinal layers in eyes with Stargardt disease (STGD). We compared selective B-scan segmentation strategies for generating mean retinal layer thickness and preserved area data from SD-OCT scans in patients with STGD1. Methods Forty-five eyes from 40 Stargardt patients were randomly selected from the ongoing Natural History of the Progression of Atrophy Secondary to Stargardt Disease (ProgStar) study. All eyes underwent SD-OCT using a standard macular volume consisting of 1024 × 49 equally spaced B-scans within a 20 × 20 degree field centered on the ...

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    22. Evaluation of Corneal Epithelial Thickness Imaged by High Definition Optical Coherence Tomography in Healthy Eyes

      Evaluation of Corneal Epithelial Thickness Imaged by High Definition Optical Coherence Tomography in Healthy Eyes

      Purpose: To evaluate corneal epithelial thickness (CET) and corneal thickness (CT) in healthy eyes using spectral domain optical coherence tomography. Methods: Thirty-six healthy eyes were imaged using the Cirrus high-definition (HD)-optical coherence tomography device. The average CET and CT were assessed using Cirrus Review Software within predefined concentric corneal ring-shaped zones. Specific regions of CET (superior, inferior, temporal, nasal, superonasal, inferotemporal, superotemporal, and inferonasal) were also assessed. The difference between zones was compared between males and females. Results: The average CET was 48.3, 47.1, 46.1, and 45.8 μm in the 4 concentric zones (0–2 ...

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    23. Evaluation of Corneal Epithelial Thickness Imaged by the High Definition Optical Coherence Tomography in Healthy Eyes

      Evaluation of Corneal Epithelial Thickness Imaged by the High Definition Optical Coherence Tomography in Healthy Eyes

      Purpose: To evaluate corneal epithelial thickness (CET) and corneal thickness (CT) in healthy eyes using spectral domain optical coherence tomography. Methods: Thirty-six healthy eyes were imaged using the Cirrus high-definition (HD)-optical coherence tomography device. The average CET and CT were assessed using Cirrus Review Software within predefined concentric corneal ring-shaped zones. Specific regions of CET (superior, inferior, temporal, nasal, superonasal, inferotemporal, superotemporal, and inferonasal) were also assessed. The difference between zones was compared between males and females. Results: The average CET was 48.3, 47.1, 46.1, and 45.8 μm in the 4 concentric zones (0–2 ...

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    24. VISUAL FUNCTION AND OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY FEATURES IN CHILDREN BORN PRETERM

      VISUAL FUNCTION AND OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY FEATURES IN CHILDREN BORN PRETERM

      Purpose: Preterm children have an increased risk of impaired vision from retinopathy, strabismus, and high refractive error. The aim of this study was to investigate the relationship between foveal parameters generated by optical coherence tomography angiography and visual function in preterm children. Methods: Eighty eyes (32 eyes of former preterm infants and 48 age-matched full-term control eyes) were analyzed. Subjects underwent complete eye examinations including best-corrected visual acuity and retinal imaging with the Optovue XR Avanti optical coherence tomography angiography device. Foveal morphologic parameters including foveal depth, central foveal thickness, inner retinal area, and outer retinal area were measured on ...

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