1. Articles from ce zheng

    1-20 of 20
    1. Dynamic analysis of iris changes and a deep learning system for automated angle-closure classification based on AS-OCT videos

      Dynamic analysis of iris changes and a deep learning system for automated angle-closure classification based on AS-OCT videos

      Background: To study the association between dynamic iris change and primary angle-closure disease (PACD) with anterior segment optical coherence tomography (AS-OCT) videos and develop an automated deep learning system for angle-closure screening as well as validate its performance. Methods: A total of 369 AS-OCT videos (19,940 frames)-159 angle-closure subjects and 210 normal controls (two datasets using different AS-OCT capturing devices)-were included. The correlation between iris changes (pupil constriction) and PACD was analyzed based on dynamic clinical parameters (pupil diameter) under the guidance of a senior ophthalmologist. A temporal network was then developed to learn discriminative temporal features ...

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    2. Generating Synthesized Ultrasound Biomicroscopy Images from Anterior Segment Optical Coherent Tomography Images by Generative Adversarial Networks for Iridociliary Assessment

      Generating Synthesized Ultrasound Biomicroscopy Images from Anterior Segment Optical Coherent Tomography Images by Generative Adversarial Networks for Iridociliary Assessment

      Introduction: The aim of this study was to investigate the feasibility of generating synthesized ultrasound biomicroscopy (UBM) images from swept-source anterior segment optical coherent tomography (SS-ASOCT) images using a cycle-consistent generative adversarial network framework (CycleGAN) for iridociliary assessment on a cohort presenting for primary angle-closure screening. Methods: The CycleGAN architecture was adopted to synthesize high-resolution UBM images trained on the SS-ASOCT dataset from the department of ophthalmology, Xinhua Hospital. The performance of the CycleGAN model was further tested in two separate datasets using synthetic UBM images from two different ASOCT modalities (in-distribution and out-of-distribution). We compared the ability of glaucoma ...

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    3. Multiview Volume and Temporal Difference Network for Angle-Closure Glaucoma Screening from AS-OCT Videos

      Multiview Volume and Temporal Difference Network for Angle-Closure Glaucoma Screening from AS-OCT Videos

      Background. Precise and comprehensive characterizations from anterior segment optical coherence tomography (AS-OCT) are of great importance in facilitating the diagnosis of angle-closure glaucoma. Existing automated analysis methods focus on analyzing structural properties identified from the single AS-OCT image, which is limited to comprehensively representing the status of the anterior chamber angle (ACA). Dynamic iris changes are evidenced as a risk factor in primary angle-closure glaucoma. Method. In this work, we focus on detecting the ACA status from AS-OCT videos, which are captured in a dark-bright-dark changing environment. We first propose a multiview volume and temporal difference network (MT-net). Our method ...

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    4. Development and Clinical Validation of Semi-Supervised Generative Adversarial Networks for Detection of Retinal Disorders in Optical Coherence Tomography Images Using Small Dataset

      Development and Clinical Validation of Semi-Supervised Generative Adversarial Networks for Detection of Retinal Disorders in Optical Coherence Tomography Images Using Small Dataset

      Purpose: To develop and test semi-supervised generative adversarial networks (GANs) that detect retinal disorders on optical coherence tomography (OCT) images using a small-labeled dataset. Methods: From a public database, we randomly chose a small supervised dataset with 400 OCT images (100 choroidal neovascularization, 100 diabetic macular edema, 100 drusen, and 100 normal) and assigned all other OCT images to unsupervised dataset (107,912 images without labeling). We adopted a semi-supervised GAN and a supervised deep learning (DL) model for automatically detecting retinal disorders from OCT images. The performance of the 2 models was compared in 3 testing datasets with different ...

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    5. Semi-supervised generative adversarial networks for closed-angle detection on anterior segment optical coherence tomography images: an empirical study with a small training dataset

      Semi-supervised generative adversarial networks for closed-angle detection on anterior segment optical coherence tomography images: an empirical study with a small training dataset

      Background: Semi-supervised learning algorithms can leverage an unlabeled dataset when labeling is limited or expensive to obtain. In the current study, we developed and evaluated a semi-supervised generative adversarial networks (GANs) model that detects closed-angle on anterior segment optical coherence tomography (AS-OCT) images using a small labeled dataset. Methods: In this cross-sectional study, a semi-supervised GANs model was developed for automatic closed-angle detection training on a small labeled and large unsupervised training dataset collected from the Joint Shantou International Eye Center of Shantou University and the Chinese University of Hong Kong (JSIEC). The closed-angle was defined as iris-trabecular contact beyond ...

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    6. Assessment of Generative Adversarial Networks for Synthetic Anterior Segment Optical Coherence Tomography Images in Closed-Angle Detection

      Assessment of Generative Adversarial Networks for Synthetic Anterior Segment Optical Coherence Tomography Images in Closed-Angle Detection

      Purpose : To develop generative adversarial networks (GANs) that synthesize realistic anterior segment optical coherence tomography (AS-OCT) images and evaluate deep learning (DL) models that are trained on real and synthetic datasets for detecting angle closure. Methods : The GAN architecture was adopted and trained on the dataset with AS-OCT images collected from the Joint Shantou International Eye Center of Shantou University and the Chinese University of Hong Kong, synthesizing open- and closed-angle AS-OCT images. A visual Turing test with two glaucoma specialists was performed to assess the image quality of real and synthetic images. DL models, trained on either real or ...

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    7. Determinants of peripapillary retinal nerve fiber layer’s grayscale value in normal eyes by spectral domain optical coherence tomography

      Determinants of peripapillary retinal nerve fiber layer’s grayscale value in normal eyes by spectral domain optical coherence tomography

      To determine and evaluate the distribution, variation, and determinants of peripapillary retinal nerve fiber layer (pRNFL) grayscale value with spectral-domain optical coherence tomography (SD-OCT) in normal eyes. In this cross-sectional study, three hundred ninety-seven normal eyes from 397 healthy Chinese adults aged 18-80 were consecutively recruited from a tertiary eye care center. An SD-OCT instrument took pRNFL imaging. We used a customized software to measure pRNFL parameters, including thickness and grayscale value. Univariable and multiple linear regression analyses were performed to examine the relationship between pRNFL grayscale value with ocular (e.g., axial length [A.L.], spherical equivalent [S.E ...

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    8. Assessment of Generative Adversarial Networks Model for Synthetic Optical Coherence Tomography Images of Retinal Disorders

      Assessment of Generative Adversarial Networks Model for Synthetic Optical Coherence Tomography Images of Retinal Disorders

      Purpose : To assess whether a generative adversarial network (GAN) could synthesize realistic optical coherence tomography (OCT) images that satisfactorily serve as the educational images for retinal specialists, and the training datasets for the classification of various retinal disorders using deep learning (DL). Methods : The GANs architecture was adopted to synthesize high-resolution OCT images trained on a publicly available OCT dataset, including urgent referrals (37,206 OCT images from eyes with choroidal neovascularization, and 11,349 OCT images from eyes with diabetic macular edema) and nonurgent referrals (8617 OCT images from eyes with drusen, and 51,140 OCT images from normal ...

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    9. Detecting glaucoma based on spectral domain optical coherence tomography imaging of peripapillary retinal nerve fiber layer: a comparison study between hand-crafted features and deep learning model

      Detecting glaucoma based on spectral domain optical coherence tomography imaging of peripapillary retinal nerve fiber layer: a comparison study between hand-crafted features and deep learning model

      Purpose To develop a deep learning (DL) model for automated detection of glaucoma and to compare diagnostic capability against hand-craft features (HCFs) based on spectral domain optical coherence tomography (SD-OCT) peripapillary retinal nerve fiber layer (pRNFL) images. Methods A DL model with pre-trained convolutional neural network (CNN) based was trained using a retrospective training set of 1501 pRNFL OCT images, which included 690 images from 153 glaucoma patients and 811 images from 394 normal subjects. The DL model was further tested in an independent test set of 50 images from 50 glaucoma patients and 52 images from 52 normal subjects ...

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    10. Evaluation of retinal vasculature before and after treatment of children with obstructive sleep apnea-hypopnea syndrome by optical coherence tomography angiography

      Evaluation of retinal vasculature before and after treatment of children with obstructive sleep apnea-hypopnea syndrome by optical coherence tomography angiography

      Purpose To evaluate the effect of adenoidectomy on the brains of children with obstructive sleep apnea-hypopnea syndrome (OSAS) through observation of the alteration of retinal perfusion by optical coherence tomography angiography (OCTA). Methods Sixty-two children with OSAS (124 eyes; 5.94 ± 1.64 years old; 53.2% boys) were enrolled in this study. Their retinal vascular network density indices, including vascular diameter (VD), vascular area density (VAD), vessel skeleton density (VSD), vessel perimeter index (VPI) on the macular superficial/deep capillary plexus (SCP/DCP), and the size of the foveal avascular zone (FAZ) were analyzed by OCTA before treatment and ...

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    11. Effect of optic disc–fovea distance on the normative classifications of macular inner retinal layers as assessed with OCT in healthy subjects

      Effect of optic disc–fovea distance on the normative classifications of macular inner retinal layers as assessed with OCT in healthy subjects

      Purpose To determine the influence of the optic disc–fovea distance (DFD) on the normative classifications based on thickness measurements of macular inner retinal layers with spectral-domain optical coherence tomography (OCT) in healthy subjects. Methods A total of 182 eyes from 182 healthy subjects were included (mean (SD) spherical equivalent −0.8 (1.9) dioptres). We performed macula and optic disc imaging with the Topcon 3D OCT 2000. The thickness of the macular inner retinal layers (macular retinal nerve fibre layer (mRNFL), ganglion cell-inner plexiform layer (GCIPL) and both combined (ganglion cell complex; GCC)) and the corresponding classifications based on ...

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    12. Profile and Determinants of Retinal Optical Intensity in Normal Eyes with Spectral Domain Optical ...

      Profile and Determinants of Retinal Optical Intensity in Normal Eyes with Spectral Domain Optical ...

      Purpose To investigate the profile and determinants of retinal optical intensity in normal subjects using 3D spectral domain optical coherence tomography (SD OCT). Methods A total of 231 eyes from 231 healthy subjects ranging in age from 18 to 80 years were included and underwent a 3D OCT scan. Forty-four eyes were randomly chosen to be scanned by two operators for reproducibility analysis. Distribution of optical intensity of each layer and regions specified by the Early Treatment of Diabetic Retinopathy Study (ETDRS) were investigated by analyzing the OCT raw data with our automatic graph-based algorithm. Univariate and multivariate analyses were ...

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    13. Pretreatment Anterior Segment Imaging During Acute Primary Angle Closure: Insights into Angle Closure Mechanisms in the Acute Phase

      Pretreatment Anterior Segment Imaging During Acute Primary Angle Closure: Insights into Angle Closure Mechanisms in the Acute Phase

      Objective To describe anterior segment optical coherence tomography (ASOCT) parameters during acute primary angle closure (APAC) before therapeutic interventions and comparative analyses of biometric parameters of APAC eyes with fellow eyes. Design Prospective, comparative case series. Participants Thirty-one consecutive patients with APAC. Methods All patients underwent ASOCT imaging of both eyes during the attack, before therapeutic interventions were administered. Custom software was used to measure anterior chamber depth (ACD), anterior chamber area (ACA), anterior chamber volume (ACV), iris curvature (I-Curv), iris area (I-Area), lens vault (LV), and angle opening distance (AOD750), trabecular iris space area (TISA750), and iris thickness (IT750 ...

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    14. Assessment of trabecular meshwork width using swept source optical coherence tomography

      Assessment of trabecular meshwork width using swept source optical coherence tomography

      Purpose Measurements of the angle width by ultrasound biomicroscopy or anterior segment optical coherence tomography are usually performed 500 μm from the scleral spur, as the anterior part of trabecular meshwork (TM) is assumed to lie within this distance. The aim of this study was to measure TM width using swept source optical coherence tomography (SS-OCT, CASIA SS-1000, Tomey Corporation, Nagoya, Japan), and to investigate factors influencing this measurement. Methods Participants underwent gonioscopy and SS-OCT imaging in the dark. High-definition SS-OCT images were corrected for refractive distortion; and customized software (ImageJ; National Institutes of Health, Bethesda, MD, USA) was utilized ...

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    15. Analysis of Anterior Segment Dynamics Using Anterior Segment Optical Coherence Tomography Before and After Laser Peripheral Iridotomy

      Analysis of Anterior Segment Dynamics Using Anterior Segment Optical Coherence Tomography Before and After Laser Peripheral Iridotomy

      Objective To evaluate changes in the speed of pupil constriction and in anterior segment parameters after laser peripheral iridotomy (LPI) in patients with angle closure using anterior segment optical coherence tomography. Methods In this prospective observational study, videos of pupil and anterior segment changes in response to illumination were captured with real-time video recording using anterior segment optical coherence tomography and were analyzed frame by frame before and after LPI. Customized software was used to measure the speed of pupil constriction and changes in anterior chamber depth and anterior chamber area, as well as iris thickness at 750 μm from ...

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    16. Swept source optical coherence tomography measurement of the iris–trabecular contact (ITC) index: a new parameter for angle closure

      Swept source optical coherence tomography measurement of the iris–trabecular contact (ITC) index: a new parameter for angle closure

      Purpose To evaluate the inter- and intra-observer agreement of measurement of the iris–trabecular contact (ITC) index, a measure of the degree of angle closure, using swept source optical coherence tomography (SSOCT, CASIA SS-1000, Tomey Corporation, Nagoya, Japan). Methods One randomly selected eye of 60 subjects was imaged under dark room conditions. The SSOCT 3-dimensional angle scan simultaneously obtains 128 radial scans of the anterior chamber for the entire circumference of the angle. Post-imaging analysis estimated the ITC index using in-built software. For intra-observer agreement for image grading, one examiner performed the grading twice in a masked fashion and random ...

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    17. Quantitative Assessment of Changes in Trabeculectomy Blebs After Laser Suture Lysis Using Anterior Segment Coherence Tomography

      Quantitative Assessment of Changes in Trabeculectomy Blebs After Laser Suture Lysis Using Anterior Segment Coherence Tomography
      Purpose: To quantify changes in bleb morphology after laser suture lysis (LSL) using anterior segment optical coherence tomography (AS-OCT). Patients and Methods: This was a prospective observational case series of patients who underwent trabeculectomy surgery with mitomycin-C and required subsequent LSL. Subjects were assessed before and immediately after LSL, and at 3 months after LSL. At each visit, a standardized cross-sectional AS-OCT image of the bleb was obtained, from which a masked observer measured bleb height (hB), cavity height (hC), wall cross sectional area (AW), cavity cross sectional area (AC), and bleb cross sectional area (AB) using custom software. Results ...
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    18. Novel anterior-chamber angle measurements by high-definition optical coherence tomography using the Schwalbe line as the landmark

      Novel anterior-chamber angle measurements by high-definition optical coherence tomography using the Schwalbe line as the landmark
      Objective To propose the Schwalbe line (SL) as a new anatomical landmark, independent of the scleral spur (SS) location, for assessing anterior chamber angle (ACA) width quantitatively with high-definition optical coherence tomography (HD-OCT). Methods Study subjects underwent dark-room gonioscopy and HD-OCT in one randomly selected eye. The authors developed a computer-aided program to define two new quantitative parameters for assessing ACA width: Schwalbe line-angle opening distance (SL-AOD) measured at the SL, and Schwalbe line-trabecular–iris space area (SL-TISA) measured 500 µm from the SL. The associations between SL parameters, SS parameters and gonioscopic grading were evaluated. Results Seventy-three (47 females ...
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    19. Changes in Angle Configuration After Phacoemulsification Measured by Anterior Segment Optical Coherence Tomography.

      Purpose: To measure changes in angle width after phacoemulsification and intraocular lens (IOL) implantation using anterior segment optical coherence tomography (AS-OCT). Materials and Methods: Twenty-one patients undergoing cataract surgery were recruited from the National University Hospital, Singapore. AS-OCT images were obtained of nasal and temporal angle quadrants before and at 1-month after surgery. Optical measurements of central anterior chamber depth were obtained, and gonioscopic measurement of angle width was recorded. AS-OCT angle width parameters measured in the nasal and temporal quadrants included the angle opening distance at 500 [mu]m (AOD500) anterior to the scleral spur and the trabecular iris ...

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    20. Changes in anterior segment morphology in response to illumination and after laser iridotomy in Asian eyes: an anterior segment OCT study

      Aim: Using the anterior segment optical coherence tomography (AS-OCT) to quantify changes in anterior segment morphology going from light to dark and following laser iridotomy (LI). Methods: Prospective observational study. 17 consecutive subjects without peripheral anterior synechiae undergoing LI were evaluated using gonioscopy and AS-OCT. Angle configuration including angle opening distance (AOD) at 500 microns anterior to the scleral spur, AOD500, trabecular-iris space area up to 750 microns from the scleral spur, TISA750 and the increase in angle opening going from dark to light conditions was determined. Results: Both mean AOD500 and TISA750 increased nearly threefold going from dark to ...

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    1-20 of 20
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    Novel anterior-chamber angle measurements by high-definition optical coherence tomography using the Schwalbe line as the landmark Quantitative Assessment of Changes in Trabeculectomy Blebs After Laser Suture Lysis Using Anterior Segment Coherence Tomography Swept source optical coherence tomography measurement of the iris–trabecular contact (ITC) index: a new parameter for angle closure Analysis of Anterior Segment Dynamics Using Anterior Segment Optical Coherence Tomography Before and After Laser Peripheral Iridotomy Assessment of trabecular meshwork width using swept source optical coherence tomography Pretreatment Anterior Segment Imaging During Acute Primary Angle Closure: Insights into Angle Closure Mechanisms in the Acute Phase Profile and Determinants of Retinal Optical Intensity in Normal Eyes with Spectral Domain Optical ... Effect of optic disc–fovea distance on the normative classifications of macular inner retinal layers as assessed with OCT in healthy subjects A Deep Learning Framework for the Detection and Quantification of Reticular Pseudodrusen and Drusen on Optical Coherence Tomography Quantitative assessment of textural features in the early detection of diabetic retinopathy with optical coherence tomography angiography Line-field confocal optical coherence tomography of fibroepithelioma of Pinkus Assessment of demineralized tooth lesions using optical coherence tomography and other state-of-the-art technologies: a review