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    1. In Vivo Subretinal ARPE-19 Cell Tracking Using Indocyanine Green Contrast-Enhanced Multimodality Photoacoustic Microscopy, Optical Coherence Tomography, and Fluorescence Imaging for Regenerative Medicine

      In Vivo Subretinal ARPE-19 Cell Tracking Using Indocyanine Green Contrast-Enhanced Multimodality Photoacoustic Microscopy, Optical Coherence Tomography, and Fluorescence Imaging for Regenerative Medicine

      Purpose: Cell-based regenerative therapies are being investigated as a novel treatment method to treat currently incurable eye diseases, such as geographic atrophy in macular degeneration. Photoacoustic imaging is a promising technology which can visualize transplanted stem cells in vivo longitudinally over time in the retina. In this study, a US Food and Drug Administration (FDA)-approved indocyanine green (ICG) contrast agent is used for labeling and tracking cell distribution and viability using multimodal photoacoustic microscopy (PAM), optical coherence tomography (OCT), and fluorescence imaging. Methods: Twelve rabbits (2.4-3.4 kg weight, 2-4 months old) were used in the study. Human ...

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    2. Development of Primary Open Angle Glaucoma-Like Features in a Rhesus Macaque Colony From Southern China

      Development of Primary Open Angle Glaucoma-Like Features in a Rhesus Macaque Colony From Southern China

      Purpose: To describe the ocular phenotype of spontaneous glaucoma in a non-human primate colony. Methods: In total, 722 Rhesus macaque monkeys aged 10 to 25 years underwent optical coherence tomography (OCT), fundus photography (FP), and intraocular pressure (IOP) measurements. Monkeys with baseline cup-to-disc ratio (CDR) <0.5 were used to establish baseline ocular features. A subset was followed longitudinally for three years and compared to glaucoma suspects on the basis of OCT/FP criteria. Results: The average IOP under ketamine sedation and average CDR for the entire colony was 13.0 ± 4.3 mm Hg and 0.38 ± 0.07 ...

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    3. Three-Dimensional Reconstruction and Swept-Source Optical Coherence Tomography for Crystalline Lens Tilt and Decentration Relative to the Corneal Vertex

      Three-Dimensional Reconstruction and Swept-Source Optical Coherence Tomography for Crystalline Lens Tilt and Decentration Relative to the Corneal Vertex

      Purpose: To investigate crystalline lens tilt and decentration with respect to the corneal vertex (CV) using swept-source optical coherence tomography (SS-OCT) combined with three-dimensional (3D) reconstruction. Methods: Thirty consecutive patients with cataract (30 right eyes) were included in this prospective, observational, pilot case series study. SS-OCT anterior segment images and 3D reconstructions were used for data analysis. Results: The mean distance between the central points of crystalline lens plane and limbus plane was approximately 0.33 ± 0.18 mm. The distance of the center of the limbus plane relative to the CV was approximately 0.31 ± 0.14 mm, which ...

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    4. In Vivo Imaging of Newt Lens Regeneration: Novel Insights Into the Regeneration Process

      In Vivo Imaging of Newt Lens Regeneration: Novel Insights Into the Regeneration Process

      Purpose : To establish optical coherence tomography (OCT) as an in vivo imaging modality for investigating the process of newt lens regeneration. Methods : Spectral-domain OCT was employed for in vivo imaging of the newt lens regeneration process. A total of 37 newts were lentectomized and followed by OCT imaging over the course of 60 to 80 days. Histological images were obtained at several time points to compare with the corresponding OCT images. Volume measurements were also acquired. Results : OCT can identify the key features observed in corresponding histological images based on the scattering differences from various eye tissues, such as the ...

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    5. Depth-Resolved Visualization of Perifoveal Retinal Vasculature in Preterm Infants Using Handheld Optical Coherence Tomography Angiography

      Depth-Resolved Visualization of Perifoveal Retinal Vasculature in Preterm Infants Using Handheld Optical Coherence Tomography Angiography

      Purpose: To establish methods to visualize depth-resolved perifoveal retinal vasculature in preterm infants using handheld optical coherence tomography angiography (OCT-A). Methods: In this exploratory study, eyes of preterm infants were imaged using an investigational noncontact, handheld swept-source OCT-A device as part of the prospective BabySTEPS infant retinal imaging study. We selected high-quality OCT-A volumes at two developmental stages for analysis. Customized MATLAB scripts were used to segment retinal layers, test offset parameters, and generate depth-resolved OCT-A slabs. The superficial (SCP), intermediate (ICP), and deep (DCP) capillary plexuses were visualized and qualitatively assessed by three image graders. Results: Six eyes from ...

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      Mentions: Duke University
    6. Optical Coherence Tomography Angiography-Derived Flux As a Measure of Physiological Changes in Retinal Capillary Blood Flow

      Optical Coherence Tomography Angiography-Derived Flux As a Measure of Physiological Changes in Retinal Capillary Blood Flow

      Purpose: To compare optical coherence tomography angiography (OCTA)-derived flux with conventional OCTA measures of retinal vascular density in assessment of physiological changes in retinal blood flow. Methods: Healthy subjects were recruited, and 3 × 3-mm2 fovea-centered scans were acquired using commercially available swept-source OCTA (SS-OCTA) while participants were breathing room air, 100% O2, or 5% CO2. Retinal perfusion was quantified using vessel area density (VAD) and vessel skeleton density (VSD), as well as novel measures of retinal perfusion, vessel area flux (VAF) and vessel skeleton flux (VSF). Flux is proportional to the number of red blood cells moving through a ...

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    7. Detection Sensitivity of Retinitis Pigmentosa Progression Using Static Perimetry and Optical Coherence Tomography

      Detection Sensitivity of Retinitis Pigmentosa Progression Using Static Perimetry and Optical Coherence Tomography

      Purpose: To compare the detection sensitivities of the progression of retinitis pigmentosa (RP) by automated perimetry to obtain the mean deviation (MD) and total point score and by optical coherence tomography (OCT) to determine the residual ellipsoid zone (EZ) length and thickness of retinal layers. Methods: Twenty-two eyes of 22 patients with RP who underwent annual automated perimetry (Humphrey Field Analyzer 10-2) and OCT examinations during the same period more than four times were included. Disease progression was evaluated using linear regression analysis with the least-squares method. The disease progression speed and interinspection fluctuations for the different examinations were compared ...

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    8. Depth-resolved Corneal Biomechanical Changes Measured Via Optical Coherence Elastography Following Corneal Crosslinking

      Depth-resolved Corneal Biomechanical Changes Measured Via Optical Coherence Elastography Following Corneal Crosslinking

      Purpose: To evaluate depth-resolved changes of corneal biomechanical properties in eyes with corneal ectasia after corneal crosslinking (CXL) using optical coherence elastography. Methods: In a prospective pilot series of eyes with corneal ectasia, a custom high-speed swept source optical coherence tomography system was used to image the cornea before and 3 months after CXL during a low-speed applanating deformation while monitoring applanation force. Cross-correlation was applied to track frame-by-frame two-dimensional optical coherence tomography speckle displacements, and the slope of force versus local axial displacement behavior during the deformation was used to produce a two-dimensional array of axial stiffness (k). These ...

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    9. Feasibility and Repeatability of Handheld Optical Coherence Tomography in Children With Craniosynostosis

      Feasibility and Repeatability of Handheld Optical Coherence Tomography in Children With Craniosynostosis

      Purpose: To determine whether handheld optical coherence tomography (OCT) is feasible and repeatable in children with craniosynostosis. Methods: This was a prospective cross-sectional study. Children with syndromic and non-syndromic craniosynostosis 0 to 18 years of age were recruited between February 13, 2020, and October 1, 2020. Main outcome measures included feasibility (patient recruitment and handheld OCT success rates) and repeatability, which were assessed using intraclass correlation coefficients (ICCs) where repeated images of the optic nerve head (ONH) within the same visit were available. ONH parameters used for repeatability analysis included cup depth, width, and area; disc width; rim height; retinal ...

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    10. Individualized Glaucoma Change Detection Using Deep Learning Auto Encoder-Based Regions of Interest

      Individualized Glaucoma Change Detection Using Deep Learning Auto Encoder-Based Regions of Interest

      Purpose : To compare change over time in eye-specific optical coherence tomography (OCT) retinal nerve fiber layer (RNFL)-based region-of-interest (ROI) maps developed using unsupervised deep-learning auto-encoders (DL-AE) to circumpapillary RNFL (cpRNFL) thickness for the detection of glaucomatous progression. Methods : Forty-four progressing glaucoma eyes (by stereophotograph assessment), 189 nonprogressing glaucoma eyes (by stereophotograph assessment), and 109 healthy eyes were followed for ≥3 years with ≥4 visits using OCT. The San Diego Automated Layer Segmentation Algorithm was used to automatically segment the RNFL layer from raw three-dimensional OCT images. For each longitudinal series, DL-AEs were used to generate individualized eye-based ROI maps ...

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      Mentions: UCSD
    11. Optical Coherence Tomography Angiography in the Thirteen-Lined Ground Squirrel

      Optical Coherence Tomography Angiography in the Thirteen-Lined Ground Squirrel

      Purpose: To assess the performance of two spectral-domain optical coherence tomography-angiography systems in a natural model of hypoperfusion: the hibernating thirteen-lined ground squirrel (13-LGS). Methods: Using a high-speed (130 kHz) OCT-A system (HS-OCT-A) and a commercial OCT (36 kHz; Bioptigen Envisu; BE-OCT-A), we imaged the 13-LGS retina throughout its hibernation cycle. Custom software was used to extract the superior, middle, and deep capillary plexus (SCP, MCP, and DCP, respectively). The retinal vasculature was also imaged with adaptive optics scanning light ophthalmoscopy (AOSLO) during torpor to visualize individual blood cells. Finally, correlative histology with immunolabeled or DiI-stained vasculature was performed. Results ...

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    12. Detection of the Microvascular Changes of Diabetic Retinopathy Progression Using Optical Coherence Tomography Angiography

      Detection of the Microvascular Changes of Diabetic Retinopathy Progression Using Optical Coherence Tomography Angiography

      Purpose: To investigate microvascular parameters that are related to the severity of diabetic retinopathy (DR) with optical coherence tomography angiography (OCTA). Methods: In total, 105 eyes from 105 diabetic patients were recruited in this prospective cross-sectional study, including 37 eyes with no clinical signs of DR (NoDR), 43 eyes with nonproliferative diabetic retinopathy (NPDR), and 25 eyes with proliferative diabetic retinopathy (PDR). Angiogram images from the parafoveal superficial capillary plexus (SCP), the deep capillary plexus (DCP), and the radial peripapillary capillary plexus were analyzed, and metrics were compared among groups. Multivariate regression analysis was used to identify the best OCTA ...

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    13. Classification of Pachychoroid on Optical Coherence Tomographic En Face Images Using Deep Convolutional Neural Networks

      Classification of Pachychoroid on Optical Coherence Tomographic En Face Images Using Deep Convolutional Neural Networks

      Purpose: To study the efficacy of deep convolutional neural networks (DCNNs) to differentiate pachychoroid from nonpachychoroid on en face optical coherence tomography (OCT) images at the large choroidal vessel. Methods: En face OCT images were collected from eyes with neovascular age-related macular degeneration, polypoidal choroidal vasculopathy, and central serous chorioretinopathy. All images were prelabeled pachychoroid or nonpachychoroid based on quantitative and qualitative criteria for choroidal morphology on multimodal imaging by two retina specialists. In total, 1188 nonpachychoroid and 884 pachychoroid images were used for training (80%) and validation (20%). Accuracy for identification of pachychoroid by DCNN models was analyzed. Trained ...

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    14. Microscope-Integrated OCT-Guided Volumetric Measurements of Subretinal Blebs Created by a Suprachoroidal Approach

      Microscope-Integrated OCT-Guided Volumetric Measurements of Subretinal Blebs Created by a Suprachoroidal Approach

      Purpose: To investigate the use of imaging modalities in the volumetric measurement of the subretinal space and examine the volume of subretinal blebs created by a subretinal drug delivery device utilizing microscope-integrated optical coherence tomography (MIOCT). Methods: An MIOCT image-based volume measurement method was developed and assessed for accuracy and reproducibility by imaging ceramic spheres of known size that were surgically implanted into ex vivo porcine eyes. This method was then used to measure subretinal blebs created in 10 porcine eyes by injection of balanced salt solution utilizing a subretinal delivery device via a suprachoroidal cannula. Bleb volumes obtained from ...

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      Mentions: Duke University
    15. Macular Ischemia Quantification Using Deep-Learning Denoised Optical Coherence Tomography Angiography in Branch Retinal Vein Occlusion

      Macular Ischemia Quantification Using Deep-Learning Denoised Optical Coherence Tomography Angiography in Branch Retinal Vein Occlusion

      Purpose: To examine whether deep-learning denoised optical coherence tomography angiography (OCTA) images could enhance automated macular ischemia quantification in branch retinal vein occlusion (BRVO). Methods: This retrospective, single-center, cross-sectional study enrolled 74 patients with BRVO and 46 age-matched healthy subjects. The severity of macular ischemia was graded as mild, moderate, or severe. Denoised OCTA images were produced using a neural network model. Quantitative parameters derived from denoised images, including vessel density and nonperfusion area, were compared with those derived from the OCTA machine. The main outcome measures were correlations between quantitative parameters, and areas under receiver operating characteristic curves (AUCs ...

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    16. Automatic Anterior Chamber Angle Classification Using Deep Learning System and Anterior Segment Optical Coherence Tomography Images

      Automatic Anterior Chamber Angle Classification Using Deep Learning System and Anterior Segment Optical Coherence Tomography Images

      Purpose: The purpose of this study was to develop a software package for the automatic classification of anterior chamber angle using anterior segment optical coherence tomography (AS-OCT). Methods: AS-OCT images were collected from subjects with open, narrow, and closure anterior chamber angles, which were graded based on ultrasound biomicroscopy (UBM) results. The Inception version 3 network and the transfer learning technique were applied in the design of an algorithm for anterior chamber angle classification. The classification performance was evaluated by fivefold cross-validation and on an independent test dataset. Results: The proposed algorithm reached a sensitivity of 0.999 and specificity ...

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    17. Visual Field Inference From Optical Coherence Tomography Using Deep Learning Algorithms: A Comparison Between Devices

      Visual Field Inference From Optical Coherence Tomography Using Deep Learning Algorithms: A Comparison Between Devices

      Purpose: To develop a deep learning model to estimate the visual field (VF) from spectral-domain optical coherence tomography (SD-OCT) and swept-source OCT (SS-OCT) and to compare the performance between them. Methods: Two deep learning models based on Inception-ResNet-v2 were trained to estimate 24-2 VF from SS-OCT and SD-OCT images. The estimation performance of the two models was evaluated by using the root mean square error between the actual and estimated VF. The performance was also compared among different glaucoma severities, Garway-Heath sectorizations, and central/peripheral regions. Results: The training dataset comprised images of 4391 eyes from 2350 subjects, and the ...

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    18. Automated Identification of Referable Retinal Pathology in Teleophthalmology Setting

      Automated Identification of Referable Retinal Pathology in Teleophthalmology Setting

      Purpose : This study aims to meet a growing need for a fully automated, learning-based interpretation tool for retinal images obtained remotely (e.g. teleophthalmology) through different imaging modalities that may include imperfect (uninterpretable) images. Methods : A retrospective study of 1148 optical coherence tomography (OCT) and color fundus photography (CFP) retinal images obtained using Topcon's Maestro care unit on 647 patients with diabetes. To identify retinal pathology, a Convolutional Neural Network (CNN) with dual-modal inputs (i.e. CFP and OCT images) was developed. We developed a novel alternate gradient descent algorithm to train the CNN, which allows for the use ...

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    19. Assessing the Clinical Utility of Expanded Macular OCTs Using Machine Learning

      Assessing the Clinical Utility of Expanded Macular OCTs Using Machine Learning

      Purpose: Optical coherence tomography (OCT) is widely used in the management of retinal pathologies, including age-related macular degeneration (AMD), diabetic macular edema (DME), and primary open-angle glaucoma (POAG). We used machine learning techniques to understand diagnostic performance gains from expanding macular OCT B-scans compared with foveal-only OCT B-scans for these conditions. Methods: Electronic medical records were extracted to obtain 61 B-scans per eye from patients with AMD, diabetic retinopathy, or POAG. We constructed deep neural networks and random forest ensembles and generated area under the receiver operating characteristic (AUROC) and area under the precision recall (AUPR) curves. Results: After extracting ...

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    20. Effect of High Myopia on Dynamic Changes of Anterior Angle After Pharmacologic Mydriasis in Cataract Patients: A SS-ASOCT Study

      Effect of High Myopia on Dynamic Changes of Anterior Angle After Pharmacologic Mydriasis in Cataract Patients: A SS-ASOCT Study

      Purpose: The purpose of this study was to evaluate the effect of high myopia on anterior angle change after pharmacologic mydriasis in patients with cataract using swept-source anterior segment optical coherence tomography (SS-ASOCT). Methods: This prospective cross-sectional study continuously recruited patients with cataract aged 40 years and older during the period August 2019 to August 2020. The anterior segment parameters, including central corneal thickness (CCT), anterior chamber depth (ACD), angle opening distance (AOD), angle recess area (ARA), trabecular iris space area (TISA), trabecular-iris angle (TIA), angle to angle width (ATA), and anterior chamber volume (ACV), were obtained using SS-ASOCT at ...

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    21. Structure-Function Mapping Using a Three-Dimensional Neuroretinal Rim Parameter Derived From Spectral Domain Optical Coherence Tomography Volume Scans

      Structure-Function Mapping Using a Three-Dimensional Neuroretinal Rim Parameter Derived From Spectral Domain Optical Coherence Tomography Volume Scans

      Purpose: To assess the structure-function relationship in glaucoma using Humphrey visual field (HVF) perimetry and a three-dimensional neuroretinal rim parameter derived from spectral domain optical coherence tomography (SD-OCT) volume scans. Methods: Structure-function correlation was analyzed globally and regionally (four quadrants and four sectors). Structural data included peripapillary retinal nerve fiber layer (RNFL) thickness and minimum distance band (MDB) neuroretinal rim thickness, defined as the shortest distance between the inner cup surface and the outer retinal pigment epithelium/Bruch's membrane complex. Logarithmic regression analyses were performed and Pearson correlation coefficients determined to assess relationship strength. Results: The study consisted of ...

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    22. Automatic Segmentation in Multiple OCT Layers For Stargardt Disease Characterization Via Deep Learning

      Automatic Segmentation in Multiple OCT Layers For Stargardt Disease Characterization Via Deep Learning

      Purpose : This study sought to perform automated segmentation of 11 retinal layers and Stargardt-associated features on spectral-domain optical coherence tomography (SD-OCT) images and to analyze differences between normal eyes and eyes diagnosed with Stargardt disease. Methods : Automated segmentation was accomplished through application of the deep learning–shortest path (DL-SP) framework, a shortest path segmentation approach that is enhanced by a deep learning fully convolutional neural network. To compare normal eyes and eyes diagnosed with Stargardt disease, various retinal layer thickness and intensity feature maps associated with the outer retinal layers were generated. Results : The automated DL-SP approach achieved a mean ...

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    23. Longitudinal Higher-Order OCT Assessment of Quantitative Fluid Dynamics and the Total Retinal Fluid Index in Neovascular AMD

      Longitudinal Higher-Order OCT Assessment of Quantitative Fluid Dynamics and the Total Retinal Fluid Index in Neovascular AMD

      Purpose : The purpose of this study was to evaluate the feasibility of assessing quantitative longitudinal fluid dynamics and total retinal fluid indices (TRFIs) with higher-order optical coherence tomography (OCT) for neovascular age-related macular degeneration (nAMD). Methods : A post hoc image analysis study was performed using the phase II OSPREY clinical trial comparing brolucizumab and aflibercept in nAMD. Higher-order OCT analysis using a machine learning−enabled fluid feature extraction platform was used to segment intraretinal fluid (IRF) and subretinal fluid (SRF) volumetric components. TRFI, the proportion of fluid volume against total retinal volume, was calculated. Longitudinal fluid metrics were evaluated for ...

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      Mentions: Cleveland Clinic
    24. Retina Vascular Perfusion Dynamics During Exercise With and Without Face Masks in Healthy Young Adults: An OCT Angiography Study

      Retina Vascular Perfusion Dynamics During Exercise With and Without Face Masks in Healthy Young Adults: An OCT Angiography Study

      Purpose: To determine possible impacts on retinal microvasculature in healthy young adults during exercise with a face mask, using optical coherence tomography angiography (OCTA). Methods: Twenty-three healthy participants (23 eyes, 17 women and 6 men) performed the incremental continuous running test (ICRT) with different masks. OCTA of the macula and optic nerve head were performed before and after ICRT to detect changes in retinal vessel density (VD). All participants were in groups A, B, and C (before ICRT) and groups A', B', and C' (after ICRT), which comprised data from volunteers without a mask, with a surgical mask, and with ...

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