1. Articles from Xiulan Zhang

    1-24 of 28 1 2 »
    1. Reproducibility of deep learning based scleral spur localisation and anterior chamber angle measurements from anterior segment optical coherence tomography images

      Reproducibility of deep learning based scleral spur localisation and anterior chamber angle measurements from anterior segment optical coherence tomography images

      Aims: To apply a deep learning model for automatic localisation of the scleral spur (SS) in anterior segment optical coherence tomography (AS-OCT) images and compare the reproducibility of anterior chamber angle (ACA) width between deep learning located SS (DLLSS) and manually plotted SS (MPSS). Methods: In this multicentre, cross-sectional study, a test dataset comprising 5166 AS-OCT images from 287 eyes (116 healthy eyes with open angles and 171 eyes with primary angle-closure disease (PACD)) of 287 subjects were recruited from four ophthalmology clinics. Each eye was imaged twice by a swept-source AS-OCT (CASIA2, Tomey, Nagoya, Japan) in the same visit ...

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    2. Assessment of Artifacts in Swept-Source Optical Coherence Tomography Angiography for Glaucomatous and Normal Eyes

      Assessment of Artifacts in Swept-Source Optical Coherence Tomography Angiography for Glaucomatous and Normal Eyes

      urpose: To evaluate the frequency of and identify the factors that influence the artifacts of swept-source optical coherence tomography angiography (SS-OCTA) in glaucomatous and normal eyes. Methods: Artifacts of OCTA images of open-angle glaucoma (OAG) and normal subjects were analyzed using SS-OCTA. Univariate and multivariate logistic regression analyses were performed to evaluate the association of age, sex, best-corrected visual acuity, axial length (AL), intraocular pressure, presence and severity of OAG, and image quality score (IQS) with the presence of artifacts. Results: Images from 4426 subjects were included in the study. At least one type of artifact was present in 24 ...

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    3. Digital Gonioscopy based on Three-dimensional Anterior Segment Optical Coherence Tomography: an international multicenter study

      Digital Gonioscopy based on Three-dimensional Anterior Segment Optical Coherence Tomography: an international multicenter study

      Objective: To develop and evaluate the performance of a three-dimensional deep-learning based automated digital gonioscopy system (3D DGS) in detecting two major characteristics in eyes suspected to have primary angle closure glaucoma (PACG): 1) narrow iridocorneal angles (static gonioscopy, Task I) and; 2) peripheral anterior synechiae (PAS) (dynamic gonioscopy, Task II) on optical coherence tomography scans. Design: International cross-sectional multicentre study. Subjects: A total of 1.112 million images of 8694 volume scans (2294 patients) from three centers were included in this study (Task I: training/internal validation/external testing - 4515, 1101, 2222 volume scans respectively; Task II: training/internal ...

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    4. Choriocapillaris Flow Deficits in Normal Chinese Imaged by Swept-Source Optical Coherence Tomographic Angiography

      Choriocapillaris Flow Deficits in Normal Chinese Imaged by Swept-Source Optical Coherence Tomographic Angiography

      Purpose To evaluate the ocular and systemic determinants of the choriocapillaris flow deficits percentage (CC FD%) in normal eyes. Design Observational cross-sectional study. Methods Healthy Chinese participants without ocular or systemic diseases underwent detailed ophthalmic evaluations, including swept-source optical coherence tomography angiography (SS-OCTA) with 6 × 6 mm macular choriocapillaris images. The CC FD% was assessed in circular regions with diameters of 1.0 and 5.0 mm, rings with 1.0–2.5-mm and 2.5–5.0-mm diameters. Results The study included 830 individuals (mean age: 58.66±8.75 years). CC FD% (mean: 22.05%±1.13%) was ...

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    5. Multi-modal Machine Learning using Visual Fields and Peripapillary Circular OCT Scans in Detection of Glaucomatous Optic Neuropathy

      Multi-modal Machine Learning using Visual Fields and Peripapillary Circular OCT Scans in Detection of Glaucomatous Optic Neuropathy

      Purpose: To develop and test a multi-modal artificial intelligence (AI) algorithm, FusionNet, using the pattern deviation probability plots (PDPs) from visual field (VF) reports and circular peripapillary optical coherence tomography (OCT) to detect glaucomatous optic neuropathy (GON). Design: Cross-sectional study. Subjects: A total of 2463 pairs of VF and OCT images from 1083 patients. Methods: A novel deep learning algorithm (FusionNet) based on bimodal input of VF-OCT paired data was developed to detect GON. VF data were collected using Humphrey Field Analyzer (HFA). OCT images were collected from three types of devices (DRI-OCT, Cirrus OCT and Spectralis OCT). A total ...

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    6. Analysis of Iris volume using swept-source optical coherence tomography in patients with type 2 diabetes mellitus

      Analysis of Iris volume using swept-source optical coherence tomography in patients with type 2 diabetes mellitus

      Purpose: To evaluate iris volume before and after pupil dilation using swept-source anterior segment optical coherence tomography (SS-ASOCT) and investigate the associated factors of iris volume and iris volume change after pupil dilation in patients with type 2 diabetes mellitus (T2DM). Methods: A cross-sectional study was conducted in Zhongshan Ophthalmic Center among T2DM registered patients in the community of Guangzhou, China. Anterior chamber volume (ACV), iris volume, anterior chamber depth (ACD), angle opening distance at 500 μm (AOD 500) and pupil diameter were estimated using SS-ASOCT (CASIA; Tomey, Nagoya, Japan). Venous blood was taken for the measurement of glycosylated haemoglobin ...

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    7. Deep Relation Transformer for Diagnosing Glaucoma with Optical Coherence Tomography and Visual Field Function

      Deep Relation Transformer for Diagnosing Glaucoma with Optical Coherence Tomography and Visual Field Function

      Glaucoma is the leading reason for irreversible blindness. Early detection and timely treatment of glaucoma are essential for preventing visual field loss or even blindness. In clinical practice, Optical Coherence Tomography (OCT) and Visual Field (VF) exams are two widely-used and complementary techniques for diagnosing glaucoma. OCT provides quantitative measurements of the optic nerve head (ONH) structure, while VF test is the functional assessment of peripheral vision. In this paper, we propose a Deep Relation Transformer (DRT) to perform glaucoma diagnosis with OCT and VF information combined. A novel deep reasoning mechanism is proposed to explore implicit pairwise relations between ...

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    8. The anterior and posterior biometric characteristics in primary angle-closure disease: Data based on anterior segment optical coherence tomography and swept-source optical coherence tomography

      The anterior and posterior biometric characteristics in primary angle-closure disease: Data based on anterior segment optical coherence tomography and swept-source optical coherence tomography

      Purpose: Obtaining a better understanding of the pathogenesis of primary angle-closure disease (PACD) still requires studies that provide measurements of anterior and posterior biometric characteristics together and that assess the relationship between them. Methods: In total, 201 eyes were enrolled in this cross-sectional study: 50 normal controls, 49 primary angle-closure suspect (PACS), 38 primary angle closure (PAC), and 64 primary angle-closure glaucoma (PACG) eyes. The anterior and posterior structural features were measured by anterior segment optical coherence tomography and swept-source optical coherence tomography. Results: All PACD groups had smaller anterior chamber depth (ACD), anterior chamber area (ACA), anterior chamber volume ...

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    9. Angle-closure assessment in anterior segment OCT images via deep learning

      Angle-closure assessment in anterior segment OCT images via deep learning

      Precise characterization and analysis of anterior chamber angle (ACA) are of great importance in facilitating clinical examination and diagnosis of angle-closure disease. Currently, the gold standard for diagnostic angle assessment is observation of ACA by gonioscopy. However, gonioscopy requires direct contact between the gonioscope and patients' eye, which is uncomfortable for patients and may deform the ACA, leading to false results. To this end, in this paper, we explore a potential way for grading ACAs into open-, appositional- and synechial angles by Anterior Segment Optical Coherence Tomography (AS-OCT), rather than the conventional gonioscopic examination. The proposed classification schema can be ...

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

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

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

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

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

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

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    12. Open-Appositional-Synechial Anterior Chamber Angle Classification in AS-OCT Sequences

      Open-Appositional-Synechial Anterior Chamber Angle Classification in AS-OCT Sequences

      Anterior chamber angle (ACA) classification is a key step in the diagnosis of angle-closure glaucoma in Anterior Segment Optical Coherence Tomography (AS-OCT). Existing automated analysis methods focus on a binary classification system (i.e., open angle or angle-closure) in a 2D AS-OCT slice. However, clinical diagnosis requires a more discriminating ACA three-class system (i.e., open, appositional, or synechial angles) for the benefit of clinicians who seek better to understand the progression of the spectrum of angle-closure glaucoma types. To address this, we propose a novel sequence multi-scale aggregation deep network (SMA-Net) for open-appositional-synechial ACA classification based on an AS-OCT ...

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    13. AGE challenge: Angle Closure Glaucoma Evaluation in Anterior Segment Optical Coherence Tomography

      AGE challenge: Angle Closure Glaucoma Evaluation in Anterior Segment Optical Coherence Tomography

      Angle closure glaucoma (ACG) is a more aggressive disease than open-angle glaucoma, where the abnormal anatomical structures of the anterior chamber angle (ACA) may cause an elevated intraocular pressure and gradually lead to glaucomatous optic neuropathy and eventually to visual impairment and blindness. Anterior Segment Optical Coherence Tomography (AS-OCT) imaging provides a fast and contactless way to discriminate angle closure from open angle. Although many medical image analysis algorithms have been developed for glaucoma diagnosis, only a few studies have focused on AS-OCT imaging. In particular, there is no public AS-OCT dataset available for evaluating the existing methods in a ...

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    14. AGE Challenge: Angle Closure Glaucoma Evaluation in Anterior Segment Optical Coherence Tomography

      AGE Challenge: Angle Closure Glaucoma Evaluation in Anterior Segment Optical Coherence Tomography

      Angle closure glaucoma (ACG) is a more aggressive disease than open-angle glaucoma, where the abnormal anatomical structures of the anterior chamber angle (ACA) may cause an elevated intraocular pressure and gradually leads to glaucomatous optic neuropathy and eventually to visual impairment and blindness. Anterior Segment Optical Coherence Tomography (AS-OCT) imaging provides a fast and contactless way to discriminate angle closure from open angle. Although many medical image analysis algorithms have been developed for glaucoma diagnosis, only a few studies have focused on AS-OCT imaging. In particular, there is no public AS-OCT dataset available for evaluating the existing methods in a ...

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    15. Automatic Segmentation and Visualization of Choroid in OCT with Knowledge Infused Deep Learning

      Automatic Segmentation and Visualization of Choroid in OCT with Knowledge Infused Deep Learning

      The choroid provides oxygen and nourishment to the outer retina thus is related to the pathology of various ocular diseases. Optical coherence tomography (OCT) is advantageous in visualizing and quantifying the choroid in vivo, because it does not suffer from the information contamination of the outer retina in fundus photography and scanning laser ophthalmoscopy and the resolution deficiency in ocular ultrasound. We propose a biomarker infused global-to-local network, for the choroid segmentation. It leverages the thickness of the choroid layer, which is a primary biomarker in clinic, as a constraint to improve the segmentation accuracy. We also design a global-to-local ...

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    16. Clock position-based iris bow configuration after laser peripheral iridotomy in Chinese angle closure eyes: a swept source optical coherence tomography study

      Clock position-based iris bow configuration after laser peripheral iridotomy in Chinese angle closure eyes: a swept source optical coherence tomography study

      Background To determine how many measurements should be evaluated to determine the iris bow and evaluate changes of iris bow at 12 clock positions after LPI in primary angle closure eyes. Methods A total of 93 primary angle closure eyes in 93 Chinese patients were enrolled. Anterior iris bowing was evaluated at 12 clock positions and 4 clock positions (3, 6, 9, and 12 o’clock) before, 1 week and 3 months after LPI using swept source optical coherence tomography. Results At baseline, almost all of the eyes exhibited an iris bow when measured using 12 clock positions, consistent with ...

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    17. Upside-down position leads to choroidal expansion and anterior chamber shallowing: OCT study

      Upside-down position leads to choroidal expansion and anterior chamber shallowing: OCT study

      Background To determine whether dynamic changes in choroidal thickness (CT) cause shallowing of the anterior chamber. Methods 34 healthy volunteers were enrolled. The participants in our study adopted the upside-down position for 1.5 min, which was the model we used to study the dynamic changes in CT. Intraocular pressure (IOP) elevation, optical coherence tomography images of the choroid and anterior chamber were obtained at baseline, after being in an upside-down position in an inversion machine and after 15 min of rest. The changes in IOP, anterior chamber and choroidal blood flow between the baseline and the upside-down position were ...

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    18. A prospective case-control study comparing optical coherence tomography characteristics in neuromyelitis optica spectrum disorder- optic neuritis and idiopathic optic neuritis

      A prospective case-control study comparing optical coherence tomography characteristics in neuromyelitis optica spectrum disorder- optic neuritis and idiopathic optic neuritis

      Background Neuromyelitis optica spectrum disorder-optic neuritis (NMOSD-ON) can now be distinguished from other types of ON as a specific disease by the Aquaporin-4 antibody (AQP4-Ab) test. NMOSD-ON can cause severe retinal nerve fiber layer (RNFL) damage. The optical coherence tomography (OCT) characteristics between NMOSD- ON and idiopathic optic neuritis (IDON) were seldom studied in Asians. Methods This prospective case-control study involved 152 eyes from 143 optic neuritis (ON) patients. All the patients were divided into either the NMOSD-ON group or the IDON group based on the AQP4-Ab test. The retinal nerve fiber layer thickness (RNFLT), retinal thickness (RT), and choroidal ...

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    19. Re: Kwon et al.: Subclassification of primary angle closure using anterior segment optical coherence tomography and ultrasound biomicroscopic parameters (Ophthalmology. 2017;124:1039-1047)

      Re: Kwon et al.: Subclassification of primary angle closure using anterior segment optical coherence tomography and ultrasound biomicroscopic parameters (Ophthalmology. 2017;124:1039-1047)

      To the Editor: We read with interest the article by Sung et al. 1 In this observational study, the authors concluded that the most distinct difference between the 2 subgroups in the cluster analysis was trabecular–ciliary process angle (TCA) and that the position of the ciliary body is important in subclassifying primary angle closure. However, there are several limitations that may affect the results. First, in the study, the authors reported that gonioscopy and image analysis using ImageJ was all conducted by a single researcher. These 2 measurements, however, both can be influenced by observers' subjectivity. To reduce influence ...

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    20. Limbus-insertion distance of superior rectus in primary angle closure glaucoma: an anterior segment OCT study

      Limbus-insertion distance of superior rectus in primary angle closure glaucoma: an anterior segment OCT study

      Objective To compare the distance from the corneoscleral limbus to the insertion site of the superior rectus of primary angle-closure glaucoma (PACG) patients with normal controls and to identify potential characteristics associated with limbus-insertion distance. Design Cross-sectional study. Participants A total of 92 subjects (eyes) were enrolled in the study: 35 were nonglaucoma controls and 57 were PACG patients. Methods The limbus-insertion distance of the superior rectus was measured by anterior segment optical coherence tomography (AS-OCT) and intraoperative surgical caliper. The anterior chamber parameters were also measured using AS-OCT to identify potential characteristics associated with limbus-insertion distance. Results The limbus-insertion ...

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    21. Effects of Valsalva Maneuver on Anterior Chamber Parameters and Choroidal Thickness in Healthy Chinese: An AS-OCT and SS-OCT Study

      Effects of Valsalva Maneuver on Anterior Chamber Parameters and Choroidal Thickness in Healthy Chinese: An AS-OCT and SS-OCT Study

      Purpose : This study concurrently evaluated the effects of the Valsalva maneuver (VM) on the anterior and posterior ocular biometric parameters in a healthy Chinese cohort. Methods : This prospective, cross-sectional study used anterior segment optical coherence tomography (AS-OCT) and swept-source optical coherence tomography (SS-OCT) to measure the anterior and posterior ocular biometric parameters before and during the VM. Sixty-three volunteers (126 eyes; 17 males and 46 females) were enrolled. The IOP, blood pressure (BP), and refractive error were recorded before and during a VM. Results : The mean IOP showed a statistically significant increase (from 13.86–14.25 mm Hg, P ...

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    22. Changes in choroidal thickness after prophylactic iridectomy in primary angle closure suspect eyes using enhanced depth imaging optical coherence tomograph

      Changes in choroidal thickness after prophylactic iridectomy in primary angle closure suspect eyes using enhanced depth imaging optical coherence tomograph

      Purpose: The aim of the present study was to evaluate the effect of surgical peripheral iridectomy (SPI) on choroidal thickness in primary angle-closure suspect (PACS) eyes. Materials and Methods: This was a prospective observational case series of 30 subjects with PACS. Ocular biometry was performed before SPI (baseline) and then 1 week later. Choroid was imaged by enhanced depth imaging optical coherence tomography (EDI-OCT). The choroidal thickness of the subfoveal area at 1 and 3 mm diameter around the fovea was determined. Central anterior chamber depth (ACD), lens thickness (LT), vitreous chamber depth (VCD), and axial length (AL) were measured ...

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    23. Changes in choroidal thickness after prophylactic iridectomy in primary angle closure suspect eyes using enhanced depth imaging optical coherence tomography

      Changes in choroidal thickness after prophylactic iridectomy in primary angle closure suspect eyes using enhanced depth imaging optical coherence tomography

      Purpose: The aim of the present study was to evaluate the effect of surgical peripheral iridectomy (SPI) on choroidal thickness in primary angle-closure suspect (PACS) eyes. Materials and Methods: This was a prospective observational case series of 30 subjects with PACS. Ocular biometry was performed before SPI (baseline) and then 1 week later. Choroid was imaged by enhanced depth imaging optical coherence tomography (EDI-OCT). The choroidal thickness of the subfoveal area at 1 and 3 mm diameter around the fovea was determined. Central anterior chamber depth (ACD), lens thickness (LT), vitreous chamber depth (VCD), and axial length (AL) were measured ...

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    24. Swept-source optical coherence tomography imaging of macular retinal and choroidal structures in healthy eyes

      Swept-source optical coherence tomography imaging of macular retinal and choroidal structures in healthy eyes

      Background To report the thickness of the retina, retinal ganglion cell (RGC)-related layers, and choroid in healthy subjects using swept source optical coherence tomography (SS-OCT). Methods One hundred and forty-six healthy volunteers were consecutively recruited for this prospective observational study. Thickness of retina, RGC-related layers, and choroid in the standard early treatment of diabetic retinopathy study (ETDRS) grid were automatically measured using one SS-OCT (DRI OCT-1, Topcon, Japan). The IOL Master (Carl Zeiss Meditec, Germany) was used to measure axial length (AL). Results Thicknesses of the average macular ganglion cell complex (GCC) and ganglion cell-inner plexiform layer (GCIPL) were ...

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    1-24 of 28 1 2 »
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    Choroidal Thickness in Fellow Eyes of Patients with Acute Primary Angle-Closure Measured by Enhanced Depth Imaging Spectral-Domain Optical Coherence Tomography Choroidal thickness in the subtypes of angle-closure: an EDI-OCT study Enhanced depth imaging-optical coherence tomography of the choroid in moderate and severe primary angle-closure glaucoma Anterior and Posterior Ocular Biometry in Healthy Chinese Subjects: Data Based on AS-OCT and SS-OCT Swept-source optical coherence tomography imaging of macular retinal and choroidal structures in healthy eyes Changes in choroidal thickness after prophylactic iridectomy in primary angle closure suspect eyes using enhanced depth imaging optical coherence tomography Changes in choroidal thickness after prophylactic iridectomy in primary angle closure suspect eyes using enhanced depth imaging optical coherence tomograph Limbus-insertion distance of superior rectus in primary angle closure glaucoma: an anterior segment OCT study Re: Kwon et al.: Subclassification of primary angle closure using anterior segment optical coherence tomography and ultrasound biomicroscopic parameters (Ophthalmology. 2017;124:1039-1047) A prospective case-control study comparing optical coherence tomography characteristics in neuromyelitis optica spectrum disorder- optic neuritis and idiopathic optic neuritis The truth about invisible posterior vitreous structures The Influence of Eyelid Position and Environmental Conditions on the Corneal Changes in Early Postmortem Interval: A Prospective, Multicentric OCT Study