1. Articles from jennifer i. lim

    1-22 of 22
    1. Transfer Learning for Automated OCTA Detection of Diabetic Retinopathy

      Transfer Learning for Automated OCTA Detection of Diabetic Retinopathy

      Purpose: To test the feasibility of using deep learning for optical coherence tomography angiography (OCTA) detection of diabetic retinopathy (DR). Methods: A deep learning convolutional neural network (CNN) architecture VGG16 was employed for this study. A transfer learning process was implemented to re-train the CNN for robust OCTA classification. In order to demonstrate the feasibility of using this method for artificial intelligence (AI) screening of DR in clinical environments, the re-trained CNN was incorporated into a custom developed GUI platform which can be readily operated by ophthalmic personnel. Results: With last nine layers re-trained, CNN architecture achieved the best performance ...

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      Mentions: Xincheng Yao
    2. Simulating vascular leakage on optical coherence tomography angiography using an overlay technique with corresponding thickness maps

      Simulating vascular leakage on optical coherence tomography angiography using an overlay technique with corresponding thickness maps

      Background To demonstrate a technique for using optical coherence tomography angiography (OCTA) to simulate leakage in eyes with diabetic macular oedema and determine the sensitivity and positive predictive value of detecting leaking microvasculature on OCTA using fluorescein angiography (FA) as the comparative norm. Methods 6×6 mm OCT angiograms were overlaid with the corresponding OCT thickness maps. Microvascular abnormalities on the OCT angiogram underlying areas of thickening on the OCT thickness map were assumed to be leaking. Two independent readers blindly read the OCTA overlay images then the FA images cropped to the same approximate region to delineate areas of ...

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    3. Supervised Machine Learning Based Multi-Task Artificial Intelligence Classification of Retinopathies

      Supervised Machine Learning Based Multi-Task Artificial Intelligence Classification of Retinopathies

      Artificial intelligence (AI) classification holds promise as a novel and affordable screening tool for clinical management of ocular diseases. Rural and underserved areas, which suffer from lack of access to experienced ophthalmologists may particularly benefit from this technology. Quantitative optical coherence tomography angiography (OCTA) imaging provides excellent capability to identify subtle vascular distortions, which are useful for classifying retinovascular diseases. However, application of AI for differentiation and classification of multiple eye diseases is not yet established. In this study, we demonstrate supervised machine learning based multi-task OCTA classification. We sought 1) to differentiate normal from diseased ocular conditions, 2) to ...

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      Mentions: Xincheng Yao
    4. Fully automated geometric feature analysis in optical coherence tomography angiography for objective classification of diabetic retinopathy

      Fully automated geometric feature analysis in optical coherence tomography angiography for objective classification of diabetic retinopathy

      This study is to establish quantitative features of vascular geometry in optical coherence tomography angiography (OCTA) and validate them for the objective classification of diabetic retinopathy (DR). Six geometric features, including total vessel branching angle (VBA: θ), child branching angles (CBAs: α1 and α2), vessel branching coefficient (VBC), and children-to-parent vessel width ratios (VWR1 and VWR2), were automatically derived from each vessel branch in OCTA. Comparative analysis of heathy control, diabetes with no DR (NoDR), and non-proliferative DR (NPDR) was conducted. Our study reveals four quantitative OCTA features to produce robust DR detection and staging classification: (ANOVA, P<0.05), VBA ...

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      Mentions: Xincheng Yao
    5. Supervised machine learning based multi-task artificial intelligence classification of retinopathies

      Supervised machine learning based multi-task artificial intelligence classification of retinopathies

      Artificial intelligence (AI) classification holds promise as a novel and affordable screening tool for clinical management of ocular diseases. Rural and underserved areas, which suffer from lack of access to experienced ophthalmologists may particularly benefit from this technology. Quantitative optical coherence tomography angiography (OCTA) imaging provides excellent capability to identify subtle vascular distortions, which are useful for classifying retinovascular diseases. However, application of AI for differentiation and classification of multiple eye diseases is not yet established. In this study, we demonstrate supervised machine learning based multi-task OCTA classification. We sought 1) to differentiate normal from diseased ocular conditions, 2) to ...

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      Mentions: Xincheng Yao
    6. OCT feature analysis guided artery-vein differentiation in OCTA

      OCT feature analysis guided artery-vein differentiation in OCTA

      Differential artery-vein analysis promises better sensitivity for retinal disease detection and classification. However, clinical optical coherence tomography angiography (OCTA) instruments lack the function of artery-vein differentiation. This study aims to verify the feasibility of using OCT intensity feature analysis to guide artery-vein differentiation in OCTA. Four OCT intensity profile features, including i) ratio of vessel width to central reflex, ii) average of maximum profile brightness, iii) average of median profile intensity, and iv) optical density of vessel boundary intensity compared to background intensity, are used to classify artery-vein source nodes in OCT. A blood vessel tracking algorithm is then employed ...

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      Mentions: Xincheng Yao
    7. QUANTITATIVE OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY FEATURES FOR OBJECTIVE CLASSIFICATION AND STAGING OF DIABETIC RETINOPATHY

      QUANTITATIVE OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY FEATURES FOR OBJECTIVE CLASSIFICATION AND STAGING OF DIABETIC RETINOPATHY

      Purpose: This study aims to characterize quantitative optical coherence tomography angiography (OCTA) features of nonproliferative diabetic retinopathy (NPDR) and to validate them for computer-aided NPDR staging. Methods: One hundred and twenty OCTA images from 60 NPDR (mild, moderate, and severe stages) patients and 40 images from 20 control subjects were used for this study conducted in a tertiary, subspecialty, academic practice. Both eyes were photographed and all the OCTAs were 6 mm × 6 mm macular scans. Six quantitative features, that is, blood vessel tortuosity, blood vascular caliber, vessel perimeter index, blood vessel density, foveal avascular zone area, and foveal avascular ...

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      Mentions: Xincheng Yao
    8. Color Fundus Image Guided Artery-Vein Differentiation in Optical Coherence Tomography Angiography

      Color Fundus Image Guided Artery-Vein Differentiation in Optical Coherence Tomography Angiography

      Purpose : This study aimed to develop a method for automated artery-vein classification in optical coherence tomography angiography (OCTA), and to verify that differential artery-vein analysis can improve the sensitivity of OCTA detection and staging of diabetic retinopathy (DR). Methods : For each patient, the color fundus image was used to guide the artery-vein differentiation in the OCTA image. Traditional mean blood vessel caliber (m-BVC) and mean blood vessel tortuosity (m-BVT) in OCTA images were quantified for control and DR groups. Artery BVC (a-BVC), vein BVC (v-BVC), artery BVT (a-BVT), and vein BVT (a-BVT) were calculated, and then the artery-vein ratio (AVR ...

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      Mentions: Xincheng Yao
    9. Analysis of Retinal Thinning Using Spectral-domain Optical Coherence Tomography Imaging of Sickle Cell Retinopathy Eyes Compared to Age- and Race-Matched Control Eyes

      Analysis of Retinal Thinning Using Spectral-domain Optical Coherence Tomography Imaging of Sickle Cell Retinopathy Eyes Compared to Age- and Race-Matched Control Eyes

      Purpose To determine whether the retina is thinner in sickle cell patients than in race- and age-matched controls, and, if it is thinner, whether there is any association with systemic diseases. Methods Sickle cell and control (age- and race-matched) patients were prospectively enrolled from a university retina clinic into this observational study. Participants underwent visual acuity testing, slit-lamp biomicroscopy, dilated ophthalmoscopy, and spectral-domain optical coherence tomography imaging. Sickle cell retinal lesions, degree of vascular tortuosity, caliber of arteriovenous anastomosis, and stage of retinopathy were noted. Early Treatment Diabetic Retinopathy Study (ETDRS) subfield measurements were compared between sickle cell and control ...

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    10. Computer-aided classification of sickle cell retinopathy using quantitative features in optical coherence tomography angiography

      Computer-aided classification of sickle cell retinopathy using quantitative features in optical coherence tomography angiography

      As a new optical coherence tomography (OCT) imaging modality, there is no standardized quantitative interpretation of OCT angiography (OCTA) characteristics of sickle cell retinopathy (SCR). This study is to demonstrate computer-aided SCR classification using quantitative OCTA features, i.e., blood vessel tortuosity (BVT), blood vessel diameter (BVD), vessel perimeter index (VPI), foveal avascular zone (FAZ) area, FAZ contour irregularity, parafoveal avascular density (PAD). It was observed that combined features show improved classification performance, compared to single feature. Three classifiers, including support vector machine (SVM), k-nearest neighbor (KNN) algorithm, and discriminant analysis, were evaluated. Sensitivity, specificity, and accuracy were quantified to ...

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    11. Quantitative characteristics of sickle cell retinopathy in optical coherence tomography angiography

      Quantitative characteristics of sickle cell retinopathy in optical coherence tomography angiography

      Early detection is an essential step for effective intervention of sickle cell retinopathy (SCR). Emerging optical coherence tomography angiography (OCTA) provides excellent three-dimensional (3D) resolution to enable label-free, noninvasive visualization of retinal vascular structures, promising improved sensitivity in detecting SCR. However, quantitative analysis of SCR characteristics in OCTA images is yet to be established. In this study, we conducted comprehensive analysis of six OCTA parameters, including blood vessel tortuosity, vessel diameter, vessel perimeter index (VPI), area of foveal avascular zone (FAZ), contour irregularity of FAZ and parafoveal avascular density. Compared to traditional retinal thickness analysis, five of these six OCTA ...

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      Mentions: Xincheng Yao
    12. Alterations in Retinal Layer Thickness and Reflectance at Different Stages of Diabetic Retinopathy by En Face Optical Coherence Tomography

      Alterations in Retinal Layer Thickness and Reflectance at Different Stages of Diabetic Retinopathy by En Face Optical Coherence Tomography

      Purpose : This article reports a method for en face optical coherence tomography (OCT) imaging and quantitative assessment of alterations in both thickness and reflectance of individual retinal layers at different stages of diabetic retinopathy (DR). Methods : High-density OCT raster volume scans were acquired in 29 diabetic subjects divided into no DR (NDR) or non-proliferative DR (NPDR) groups and 22 control subjects (CNTL). A customized image segmentation method identified eight retinal layer interfaces and generated en face thickness maps and reflectance images for nerve fiber layer (NFL), ganglion cell and inner plexiform layers (GCLIPL), inner nuclear layer (INL), outer plexiform layer ...

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      Mentions: Mahnaz Shahidi
    13. Cross-sectional analysis of neurocognitive function, retinopathy, and retinal thinning by spectral-domain optical coherence tomography in sickle cell patients

      Cross-sectional analysis of neurocognitive function, retinopathy, and retinal thinning by spectral-domain optical coherence tomography in sickle cell patients

      Purpose: The purpose was to examine the relationship between neurocognitive function and two distinct forms of retinopathy in sickle cell disease. Materials and Methods: Patients with sickle cell disease (n = 44, age range: 19-56 years, 70% female) were prospectively recruited for this cross-sectional study. Retinopathy was characterized by: (1) Presence of focal retinal thinning on spectral domain optical coherence tomography and (2) determination of the sickle retinopathy stage on funduscopic exam based on Goldberg classification. Neurocognitive function was assessed using the Philadelphia Brief Assessment of Cognition (PBAC), a validated test of cognition. Univariate and multivariate analyses for PBAC score outcomes ...

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    14. Inner and outer retinal thickness mapping of nonproliferative diabetic retinopathy by spectral-domain optical coherence tomography

      Inner and outer retinal thickness mapping of nonproliferative diabetic retinopathy by spectral-domain optical coherence tomography

      BACKGROUND AND OBJECTIVE: To report inner retinal thickness (IRT), outer retinal thickness (ORT), and total retinal thickness (TRT) mapping of nonproliferative diabetic retinopathy (DR). PATIENTS AND METHODS: Spectral-domain optical coherence tomography (SD-OCT) images were obtained in 31 study participants with nonproliferative DR. Semi-automated software generated IRT, ORT, and TRT maps. IRT, ORT, and TRT in each macular subfield were compared between groups with and without increased central subfield thickness. RESULTS: There were statistically significant differences in IRT, ORT, and TRT between groups ( P < .007). In participants with nonproliferative DR with increased central subfield thickness, TRT was significantly increased in parafoveal ...

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    15. A Method for En Face OCT Imaging of Subretinal Fluid in Age-Related Macular Degeneration

      A Method for En Face OCT Imaging of Subretinal Fluid in Age-Related Macular Degeneration

      Purpose . The purpose of the study is to report a method for en face imaging of subretinal fluid (SRF) due to age-related macular degeneration (AMD) based on spectral domain optical coherence tomography (SDOCT). Methods . High density SDOCT imaging was performed at two visits in 4 subjects with neovascular AMD and one healthy subject. En face OCT images of a retinal layer anterior to the retinal pigment epithelium were generated. Validity, repeatability, and utility of the method were established. Results . En face OCT images generated by manual and automatic segmentation were nearly indistinguishable and displayed similar regions of SRF. En face ...

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      Mentions: Mahnaz Shahidi
    16. Wavefront Error Correction with Adaptive Optics in Diabetic Retinopathy

      Wavefront Error Correction with Adaptive Optics in Diabetic Retinopathy

      Purpose: To determine the effects of diabetic retinopathy (DR), increased foveal thickness (FT), and adaptive optics (AO) on wavefront aberrations and Shack-Hartmann (SH) image quality. Methods: Shack-Hartmann aberrometry and wavefront error correction were performed with a bench-top AO retinal imaging system in 10 healthy control and 19 DR subjects. Spectral domain optical coherence tomography was performed and central FT was measured. Based on the FT data in the control group, subjects in the DR group were categorized into two subgroups: those with normal FT and those with increased FT. Shack-Hartmann image quality was assessed based on spot areas, and high-order ...

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      Mentions: Mahnaz Shahidi
    17. Peripapillary Retinal Nerve Fiber Layer Thickness in Sickle-Cell Hemoglobinopathies Using Spectral-Domain Optical Coherence Tomography

      Peripapillary Retinal Nerve Fiber Layer Thickness in Sickle-Cell Hemoglobinopathies Using Spectral-Domain Optical Coherence Tomography

      Purpose To determine whether patients with a sickle-cell hemoglobinopathy without glaucoma have peripapillary retinal nerve fiber layer (RNFL) thinning by spectral-domain optical coherence tomography. Design Prospective study. Methods All patients with a sickle cell hemoglobinopathy (sickle-cell disease, sickle-cell hemoglobin C disease, and sickle-cell thalassemia) and age-similar, race-matched controls underwent a comprehensive eye examination and spectral-domain optical coherence tomography of the macula and optic nerve head using the Heidelberg Spectralis (Heidelberg Engineering, Inc, Carlsbad, California, USA). Participants with prior retinal treatments (laser or surgery), diabetes mellitus, glaucoma, or other ocular diseases were excluded. The sickle-cell disease patients were grouped into those ...

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    18. En Face Spectral-Domain Optical Coherence Tomography Outer Retinal Analysis and Relation to Visual Acuity

      En Face Spectral-Domain Optical Coherence Tomography Outer Retinal Analysis and Relation to Visual Acuity

      Purpose: To describe a method of en face visualization and quantification of the photoreceptor inner segment/outer segment junction area, using spectral-domain optical coherence tomography, and association with visual acuity. Methods: Case series of 74 eyes in 53 patients. Central 1-mm and 400-[mu]m en face areas were analyzed with a computer algorithm. Results: The presence or absence of inner segment/outer segment junction was visible on both spectral-domain optical coherence tomography en face and retinal cross sections. Thirty eyes (40.6%) had no retinal pathology and an average logMAR visual acuity of 0.116. Twenty-five eyes (33.8 ...

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    19. Feasibility of a Method for En Face Imaging of Photoreceptor Cell Integrity

      Feasibility of a Method for En Face Imaging of Photoreceptor Cell Integrity

      Purpose To report a method for en face imaging of the photoreceptor inner and outer segment junction by spectral-domain optical coherence tomography (SD OCT) and to describe findings in normal subjects and patients with various retinal diseases. Design Observational case series. Methods SD OCT images were acquired from 6 normal subjects (mean age, 44 ± 11 years) and from 5 subjects with retinal diseases (mean age, 66 ± 22 years). A customized high-density SD OCT volume scan was acquired on the retina. SD OCT B-scan images were segmented automatically to extract intensity data along the inner and outer segment junction. Data obtained ...

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      Mentions: Mahnaz Shahidi
    20. Structural and Functional Correlation in Sickle Cell Retinopathy Using Spectral-Domain Optical Coherence Tomography and Scanning Laser Ophthalmoscope Microperimetry

      Structural and Functional Correlation in Sickle Cell Retinopathy Using Spectral-Domain Optical Coherence Tomography and Scanning Laser Ophthalmoscope Microperimetry
      Purpose: To correlate macular structural changes by spectral-domain optical coherence tomography (SD-OCT) with functional changes by scanning laser ophthalmoscope (SLO) microperimetry testing in patients with sickle cell hemoglobinopathies.Design: Prospective, investigational study.Methods: Patients with electrophoretic confirmation of sickle cell hemoglobinopathies and normal subjects underwent SD-OCT and microperimetry testing with the OPKO Spectral OCT/SLO instrument. Based on SD-OCT findings, patients were grouped into those with focal macular thinning (Group A) and those without (Group B). Main outcome measure were mean retinal sensitivities measured by microperimetry and mean macular thicknesses in the 9 Early Treatment Diabetic Retinopathy Study (ETDRS)-like ...
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      Mentions: Optos
    21. Central Macular Splaying and Outer Retinal Thinning in Asymptomatic Sickle Cell Patients by Spectral-Domain Optical Coherence Tomography

      Central Macular Splaying and Outer Retinal Thinning in Asymptomatic Sickle Cell Patients by Spectral-Domain Optical Coherence Tomography

      Purpose To investigate the prevalence and degree of macular thinning on optical coherence tomography (SDOCT) in African-American female patients with asymptomatic sickle cell disease. Design Prospective comparative case series. Methods Twenty-one sickle cell patients (42 eyes) without other systemic or ocular diseases and 18 healthy control patients (33 eyes) underwent SD-OCT. Images were manually segmented to measure inner retinal thickness (IRT) and outer retinal thickness (ORT). Central macular (central 1 mm), parafoveal (0.5–1.5 mm eccentricity), and perifoveal (1.5–3 mm eccentricity) thickness measurements were obtained in sickle cell patients and age/gender/race-matched healthy control subjects ...

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      Mentions: Mahnaz Shahidi
    22. A Pilot Study of Fourier-Domain Optical Coherence Tomography of Retinal Dystrophy Patients

      Purpose To characterize the macular anatomy of retinal dystrophy eyes using high-speed, high-resolution, Fourier-domain optical coherence tomography (FD-OCT). Design Case-control study. Methods Retinal dystrophy patients and normal age- and gender-matched controls underwent FD-OCT imaging using the RTVue (Optovue Inc, Fremont, California, USA). Vertical and horizontal 8-mm scans of 1024 lines/cross-section were obtained. Based on boundaries manually drawn on computer displays of OCT cross-sections, the thicknesses of the retina, inner retinal layer (IRL), and outer retinal layer (ORL) were averaged over both 5-mm (macular) and 1.5-mm (foveal) regions centered at the fovea. The IRL was the sum of nerve ...
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    1-22 of 22
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    Central Macular Splaying and Outer Retinal Thinning in Asymptomatic Sickle Cell Patients by Spectral-Domain Optical Coherence Tomography Structural and Functional Correlation in Sickle Cell Retinopathy Using Spectral-Domain Optical Coherence Tomography and Scanning Laser Ophthalmoscope Microperimetry Feasibility of a Method for En Face Imaging of Photoreceptor Cell Integrity En Face Spectral-Domain Optical Coherence Tomography Outer Retinal Analysis and Relation to Visual Acuity Peripapillary Retinal Nerve Fiber Layer Thickness in Sickle-Cell Hemoglobinopathies Using Spectral-Domain Optical Coherence Tomography Wavefront Error Correction with Adaptive Optics in Diabetic Retinopathy A Method for En Face OCT Imaging of Subretinal Fluid in Age-Related Macular Degeneration Inner and outer retinal thickness mapping of nonproliferative diabetic retinopathy by spectral-domain optical coherence tomography Cross-sectional analysis of neurocognitive function, retinopathy, and retinal thinning by spectral-domain optical coherence tomography in sickle cell patients In vivo evaluation of corneal biomechanical properties by optical coherence elastography at different cross-linking irradiances The Association of Optical Coherence Tomography Results With Neuroimaging Signs and Some Clinical Parameters in Idiopathic Intracranial Hypertension Low cost scalable monolithic common path probe design for the application in endoscopic optical coherence tomography