1. Articles from Ching-Yu Cheng

    1-25 of 25
    1. Normative data and associations of Optical Coherence Tomography Angiography measurements of the macula: The Singapore Malay Eye Study

      Normative data and associations of Optical Coherence Tomography Angiography measurements of the macula: The Singapore Malay Eye Study

      Objective: To describe the normative quantitative parameters of macular retinal vasculature and their systemic and ocular associations, using optical coherence tomography angiography (OCTA). Design: Population based cross sectional study SUBJECTS: Adults above 50 years old were recruited from the third examination of the population-based Singapore Malay Eye Study. Methods: All participants underwent standardized comprehensive examination and Spectral domain-OCTA (Optovue, USA) of the macula. OCTA scans with pre-existing retinal disease, macular pathology, and poor quality were excluded. Main outcome measures: Normative quantitative vessel densities of the superficial, deep layer and foveal avascular zone were evaluated. Ocular and systemic associations with macular ...

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    2. Computer-aided detection and abnormality score for the outer retinal layer in optical coherence tomography

      Computer-aided detection and abnormality score for the outer retinal layer in optical coherence tomography

      Background: To develop computer-aided detection (CADe) of ORL abnormalities in the retinal pigmented epithelium, interdigitation zone and ellipsoid zone via optical coherence tomography (OCT). Methods: In this retrospective study, healthy participants with normal ORL, and patients with abnormality of ORL including choroidal neovascularisation (CNV) or retinitis pigmentosa (RP) were included. First, an automatic segmentation deep learning (DL) algorithm, CADe, was developed for the three outer retinal layers using 120 handcraft masks of ORL. This automatic segmentation algorithm generated 4000 segmentations, which included 2000 images with normal ORL and 2000 (1000 CNV and 1000 RP) images with focal or wide defects ...

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    3. Utilisation of poor-quality optical coherence tomography scans: adjustment algorithm from the Singapore Epidemiology of Eye Diseases (SEED) study

      Utilisation of poor-quality optical coherence tomography scans: adjustment algorithm from the Singapore Epidemiology of Eye Diseases (SEED) study

      Purpose To evaluate the effect of signal strength (SS) on optical coherence tomography (OCT) parameters, and devise an algorithm to adjust the effect, when acceptable SS cannot be obtained. Methods 5085 individuals (9582 eyes), aged ≥40 years from the Singapore Epidemiology of Eye Diseases population-based study were included. Everyone underwent a standardised ocular examination and imaging with Cirrus HD-OCT. Effect of SS was evaluated using multiple structural breaks linear mixed-effect models. Expected change for increment in SS between 4 and 10 for individual parameter was calculated. Subsequently we devised and evaluated an algorithm to adjust OCT parameters to higher SS ...

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    4. Deep learning in glaucoma with optical coherence tomography: a review

      Deep learning in glaucoma with optical coherence tomography: a review

      Deep learning (DL), a subset of artificial intelligence (AI) based on deep neural networks, has made significant breakthroughs in medical imaging, particularly for image classification and pattern recognition. In ophthalmology, applying DL for glaucoma assessment with optical coherence tomography (OCT), including OCT traditional reports, two-dimensional (2D) B-scans, and three-dimensional (3D) volumetric scans, has increasingly raised research interests. Studies have demonstrated that using DL for interpreting OCT is efficient, accurate, and with good performance for discriminating glaucomatous eyes from normal eyes, suggesting that incorporation of DL technology in OCT for glaucoma assessment could potentially address some gaps in the current practice ...

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    5. Deep learning algorithms to isolate and quantify the structures of the anterior segment in optical coherence tomography images

      Deep learning algorithms to isolate and quantify the structures of the anterior segment in optical coherence tomography images

      Background/Aims Accurate isolation and quantification of intraocular dimensions in the anterior segment (AS) of the eye using optical coherence tomography (OCT) images is important in the diagnosis and treatment of many eye diseases, especially angle-closure glaucoma. Method In this study, we developed a deep convolutional neural network (DCNN) for the localisation of the scleral spur; moreover, we introduced an information-rich segmentation approach for this localisation problem. An ensemble of DCNNs for the segmentation of AS structures (iris, corneosclera shell adn anterior chamber) was developed. Based on the results of two previous processes, an algorithm to automatically quantify clinically important ...

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    6. Detection of features associated with neovascular age-related macular degeneration in ethnically distinct data sets by an optical coherence tomography: trained deep learning algorithm

      Detection of features associated with neovascular age-related macular degeneration in ethnically distinct data sets by an optical coherence tomography: trained deep learning algorithm

      Background The ability of deep learning (DL) algorithms to identify eyes with neovascular age-related macular degeneration (nAMD) from optical coherence tomography (OCT) scans has been previously established. We herewith evaluate the ability of a DL model, showing excellent performance on a Korean data set, to generalse onto an American data set despite ethnic differences. In addition, expert graders were surveyed to verify if the DL model was appropriately identifying lesions indicative of nAMD on the OCT scans. Methods Model development data set—12 247 OCT scans from South Korea; external validation data set—91 509 OCT scans from Washington, USA ...

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    7. Systemic hypertension associated retinal microvascular changes can be detected with optical coherence tomography angiography

      Systemic hypertension associated retinal microvascular changes can be detected with optical coherence tomography angiography

      A major complication of hypertension is microvascular damage and capillary rarefaction is a known complication of hypertensive end-organ damage which confers a higher risk of systemic disease such as stroke and cardiovascular events. Our aim was to study the effect of hypertension on the retinal microvasculature using non-invasive optical coherence tomography angiography (OCTA). We performed a case-control study of 94 eyes of 94 participants with systemic hypertension and 46 normal control eyes from the Singapore Chinese Eye Study using a standardized protocol to collect data on past medical history of hypertension, including the number and type of hypertensive medications and ...

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    8. Agreement in Measures of Macular Perfusion between Optical Coherence Tomography Angiography Machines

      Agreement in Measures of Macular Perfusion between Optical Coherence Tomography Angiography Machines

      We evaluated the agreements in foveal avascular zone (FAZ) area and vessel density (VD) parameters (within the superficial capillary plexus region), between two widely used optical coherence tomography angiography machines. Participants who attended the Singapore Malay Eye Study III between 29th March and 6th August 2018, were enrolled in this study. Participants underwent fovea-centered 6×6-mm macular cube scan, using both AngioVue and Cirrus HDOCT machines. Scans were analyzed automatically using built-in review software of each machine. 177 eyes (95 participants) without retinal diseases were included for final analysis. Mean FAZ area was 0.38 ± 0.11 mm 2 and ...

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    9. Association between Macular Thickness Profiles and Visual Function in Healthy Eyes: The Singapore Epidemiology of Eye Diseases (SEED) Study

      Association between Macular Thickness Profiles and Visual Function in Healthy Eyes: The Singapore Epidemiology of Eye Diseases (SEED) Study

      This study aimed to evaluate the association between optical coherence tomography (OCT)-measured retinal layer thickness parameters with clinical and patient-centred visual outcomes in healthy eyes. Participants aged 40 and above were recruited from the Singapore Epidemiology of Eye Diseases Study, a multi-ethnic population-based study. Average macular, ganglion cell-inner plexiform layer (GCIPL), and outer retinal thickness parameters were obtained using the Cirrus High Definition-OCT. Measurements of best-corrected visual acuity (BCVA) and 11-item visual functioning questionnaire (VF-11) were performed. Associations between macular thickness parameters, with BCVA and Rasch-transformed VF-11 scores (in logits) were assessed using multivariable linear regression models with generalized ...

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    10. Towards Label-Free 3D Segmentation of Optical Coherence Tomography Images of the Optic Nerve Head Using Deep Learning

      Towards Label-Free 3D Segmentation of Optical Coherence Tomography Images of the Optic Nerve Head Using Deep Learning

      Since the introduction of optical coherence tomography (OCT), it has been possible to study the complex 3D morphological changes of the optic nerve head (ONH) tissues that occur along with the progression of glaucoma. Although several deep learning (DL) techniques have been recently proposed for the automated extraction (segmentation) and quantification of these morphological changes, the device-specific nature and the difficulty in preparing manual segmentations (training data) limit their clinical adoption. With several new manufacturers and next-generation OCT devices entering the market, the complexity in deploying DL algorithms clinically is only increasing. To address this, we propose a DLbased 3D ...

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    11. Deep Learning Algorithms to Isolate and Quantify the Structures of the Anterior Segment in Optical Coherence Tomography Images

      Deep Learning Algorithms to Isolate and Quantify the Structures of the Anterior Segment in Optical Coherence Tomography Images

      Accurate isolation and quantification of intraocular dimensions in the anterior segment (AS) of the eye using optical coherence tomography (OCT) images is important in the diagnosis and treatment of many eye diseases, especially angle closure glaucoma. In this study, we developed a deep convolutional neural network (DCNN) for the localization of the scleral spur, and the segmentation of anterior segment structures (iris, corneo-sclera shell, anterior chamber). With limited training data, the DCNN was able to detect the scleral spur on unseen ASOCT images as accurately as an experienced ophthalmologist; and simultaneously isolated the anterior segment structures with a Dice coefficient ...

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    12. Compensation of retinal nerve fibre layer thickness as assessed using optical coherence tomography based on anatomical confounders

      Compensation of retinal nerve fibre layer thickness as assessed using optical coherence tomography based on anatomical confounders

      Background/Aims To compensate the retinal nerve fibre layer (RNFL) thickness assessed by spectral-domain optical coherence tomography (SD-OCT) for anatomical confounders. Methods The Singapore Epidemiology of Eye Diseases is a population-based study, where 2698 eyes (1076 Chinese, 704 Malays and 918 Indians) with high-quality SD-OCT images from individuals without eye diseases were identified. Optic disc and macular cube scans were registered to determine the distance between fovea and optic disc centres (fovea distance) and their respective angle (fovea angle). Retinal vessels were segmented in the projection images and used to calculate the circumpapillary retinal vessel density profile. Compensated RNFL thickness ...

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    13. Assessment of Circumferential Angle Closure with Swept-Source Optical Coherence Tomography: a community based study

      Assessment of Circumferential Angle Closure with Swept-Source Optical Coherence Tomography: a community based study

      Purpose To evaluate the diagnostic performance of swept-source optical coherence tomography (SS-OCT, CASIA SS-1000, Tomey Corporation, Nagoya, Japan) for angle closure detection, in comparison with gonioscopy in a community setting. Design Reliability analysis. Methods A total of 2027 phakic subjects aged ≥50 years, with no previous history of glaucoma, laser (including peripheral iridotomy), intraocular surgery or ocular trauma, were consecutively recruited from a community polyclinic in Singapore. Gonioscopy was performed by a single trained ophthalmologist. SS-OCT angle scans, which obtain radial scans for the entire circumference of the angle, were analyzed by a single examiner, masked to the subject’s ...

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    14. Correlation of Color Fundus Photograph Grading with Risks of Early Age-related Macular Degeneration by using Automated OCT-derived Drusen Measurements

      Correlation of Color Fundus Photograph Grading with Risks of Early Age-related Macular Degeneration by using Automated OCT-derived Drusen Measurements

      We evaluated automated OCT-derived drusen volume measures in a population-based study (n = 4,512) aged ≥40 years, and its correlation with conventional color fundus photographs (CFP)-derived early AMD features. Participants had protocol-based assessment to capture medical and ocular history, genotyping for SNPs in CFH , ARMS2 , and CETP , CFP-based AMD grading and automated drusen volume based on SD-OCT using built-in software (Cirrus OCT advanced RPE analysis software). Significantly fewer eyes with early AMD features (drusen, hyperpigmentation, soft or reticular drusen) had drusen volume = 0 mm 3 (p < 0.001). In eyes with drusen volume > 0 mm 3 , increasing AMD severity ...

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    15. Imaging of the lamina cribrosa and its role in glaucoma: a review

      Imaging of the lamina cribrosa and its role in glaucoma: a review

      The lamina cribrosa of the optic nerve head serves two contrasting roles; it must be porous to allow retinal ganglion cell axons to pass through, and yet at the same time, it must also provide adequate structural support to withstand the stresses and strains across it. Improvements in imaging such as optical coherence tomography image capture and image processing have allowed detailed in vivo studies of lamina cribrosa macro- and micro-architectural characteristics. This has aided our understanding of the optic nerve head as a complex biomechanical structure. In this review, we first aim to frame the biomechanical considerations of lamina ...

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    16. Factors affecting signal strength in spectral-domain optical coherence tomography

      Factors affecting signal strength in spectral-domain optical coherence tomography

      Purpose To identify ocular factors that affect signal strength in spectral-domain optical coherence tomography (SD-OCT). Methods Data from 1312 participants of the population-based Singapore Malay Eye Study-2 (SiMES-2) were included in the analysis. All participants underwent standardized ophthalmic examination, including measurements of best-corrected visual acuity (BCVA), refractive error, axial length, corneal curvature and presence of cataracts. Optic disc and macular cube scans were acquired using the Cirrus HD-OCT (software version 6.0, Carl Zeiss Meditec, Dublin, CA, USA). Signal strength of the optical coherence tomography (OCT) scan was recorded for each study eye. Multivariable linear regression analyses were performed to ...

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    17. Detailed Phenotyping and Characterization of Choroidal Morphological and Vascular Features in Young Men with High Myopia Using Spectral-Domain Optical Coherence Tomography

      Detailed Phenotyping and Characterization of Choroidal Morphological and Vascular Features in Young Men with High Myopia Using Spectral-Domain Optical Coherence Tomography

      Purpose To describe detailed morphological and vascular features of the choroid in eyes with high myopia. Design Cross-sectional study. Methods 515 eyes of young men (mean age 21.59±1.15) years) with high myopia (defined as -6.0 D or worse, mean spherical equivalent -8.66±2.00 D) and 88 controls with emmetropia in both eyes underwent choroidal imaging using spectral domain optical coherence tomography with enhanced depth imaging (EDI-OCT). Raw OCT images were loaded on a custom-written application on MATLAB that enabled delineation for detailed morphological and vascular analyses, including the distance of thickest point from the ...

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    18. A Digital Staining Algorithm for Optical Coherence Tomography Images of the Optic Nerve Head

      A Digital Staining Algorithm for Optical Coherence Tomography Images of the Optic Nerve Head

      Purpose : To digitally stain spectral-domain optical coherence tomography (OCT) images of the optic nerve head (ONH), and highlight either connective or neural tissues. Methods : OCT volumes of the ONH were acquired from one eye of 10 healthy subjects. We processed all volumes with adaptive compensation to remove shadows and enhance deep tissue visibility. For each ONH, we identified the four most dissimilar pixel-intensity histograms, each of which was assumed to represent a tissue group. These four histograms formed a vector basis on which we ‘projected' each OCT volume in order to generate four digitally stained volumes P1 to P4. Digital ...

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    19. Association of iris surface features with iris parameters assessed by swept-source optical coherence tomography in Asian eyes

      Association of iris surface features with iris parameters assessed by swept-source optical coherence tomography in Asian eyes

      Background/aims To characterise the association of iris surface features (crypts, furrows and colour) with iris volume and curvature assessed by swept-source optical coherence tomography (SSOCT) in Asian eyes. Methods Iris crypts (by number and size) and furrows (by number and circumferential extent) were graded from iris photographs. Iris colour was measured by a customised algorithm written on MATLAB (MathWorks, Natick, Massachusetts, USA). The iris was imaged by SSOCT (SS-1000, CASIA, Tomey, Nagoya, Japan). The associations of surface features with iris parameters were analysed using a generalised estimating equation. Results A total of 1704 subjects (3297 eyes) were included in ...

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    20. Automatic Feature Extraction of Optical Coherence Tomography for Lamina Cribrosa Detection

      Automatic Feature Extraction of Optical Coherence Tomography for Lamina Cribrosa Detection

      T his paper presents a framework to segment and extract key features automatically in Optical Coherence Tomography (OCT) scans. One of the main features to be detected is the Lamina Cribrosa (LC), which is an optic nerve head structure believed to play a crucial role in glaucomatous optic neuropathy. Detection of the LC aids in understanding pathogenesis and detection of glaucoma. Automatic segmentation allows a quick and objective way of identifying the LC. In previous work, LC segmentation has been manual; hence, the aim is to achieve automatic and accurate segmentation. Automatic detection is a novel approach, and very important ...

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    21. Relationship of ocular and systemic factors to the visibility of choroidal–scleral interface using spectral domain optical coherence tomography

      Relationship of ocular and systemic factors to the visibility of choroidal–scleral interface using spectral domain optical coherence tomography

      Purpose To assess the visibility of the choroidal–scleral interface (CSI) from spectral domain optical coherence tomography (SD-OCT) and evaluate the ocular and systemic factors influencing the visibility of CSI in healthy eyes from population-based Malay sample. Methods Participants were consecutively recruited from the population-based Singapore Malay Eye Study-2 (SiMES-2). SD-OCT images were obtained by Spectralis OCT with enhanced depth imaging (EDI) mode. Visibility of CSI was assessed by a grading system ranging from 0 to 2 scores. The reliability of choroidal thickness measurement in different grades of CSI visibility was assessed using intraclass correlation coefficient. Ordinal regression analyses were ...

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    22. Determinants of Optical Coherence Tomography–Derived Minimum Neuroretinal Rim Width in a Normal Chinese Population

      Determinants of Optical Coherence Tomography–Derived Minimum Neuroretinal Rim Width in a Normal Chinese Population

      Purpose. To characterize an optical coherence tomography (OCT)–derived parameter, Bruch's membrane opening–minimum rim width (BMO-MRW), and its association with demographic and clinical parameters in normal Chinese subjects. Methods. Right eyes of 466 consecutive healthy subjects from a population-based study of Singaporean Chinese underwent Cirrus OCT imaging. The retinal internal limiting membrane (ILM) and BMO were automatically delineated using the built-in Cirrus algorithm. The standard 36 interpolated radial B-scans (72 BMO points, 5° increments) of each optic nerve head were manually extracted from the central circle (3.46-mm diameter). We used Matlab to measure the shortest distance from ...

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    23. A Simplified Method to Measure Choroidal Thickness Using Adaptive Compensation in Enhanced Depth Imaging Optical Coherence Tomography

      A Simplified Method to Measure Choroidal Thickness Using Adaptive Compensation in Enhanced Depth Imaging Optical Coherence Tomography

      Purpose To evaluate a simplified method to measure choroidal thickness (CT) using commercially available enhanced depth imaging (EDI) spectral domain optical coherence tomography (SD-OCT). Methods We measured CT in 31 subjects without ocular diseases using Spectralis EDI SD-OCT. The choroid-scleral interface of the acquired images was first enhanced using a post-processing compensation algorithm. The enhanced images were then analysed using Photoshop. Two graders independently graded the images to assess inter-grader reliability. One grader re-graded the images after 2 weeks to determine intra-grader reliability. Statistical analysis was performed using intra-class correlation coefficient (ICC) and Bland-Altman plot analyses. Results Using adaptive compensation ...

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    24. Sectoral variations of iridocorneal angle width and iris volume in Chinese Singaporeans: a swept-source optical coherence tomography study

      Sectoral variations of iridocorneal angle width and iris volume in Chinese Singaporeans: a swept-source optical coherence tomography study

      Purpose To assess variations in the iridocorneal angle width and iris volume in Chinese subjects using swept-source optical coherence tomography (SS-OCT). Methods Consecutive subjects, aged 40–80 years, with no previous ophthalmic problems were recruited from a population-based study of Chinese Singaporeans. All subjects underwent 360° SS-OCT (SS-1000 CASIA, Tomey Corporation, Nagoya, Japan) angle imaging and gonioscopy in one randomly selected eye in the dark. For each eye, 16 frames (11.25° apart) were selected for analysis from 128 cross-sectional images, and measurements of the trabecular iris space area 750 μm from the scleral spur (TISA750) and iris volume were ...

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    25. Determinants of Macular Thickness using Spectral Domain Optical Coherence Tomography in Healthy Eyes: the Singapore Chinese Eye Study

      Determinants of Macular Thickness using Spectral Domain Optical Coherence Tomography in Healthy Eyes: the Singapore Chinese Eye Study

      Purpose:To determine ocular and systemic factors influencing macular thickness measured by SD-OCT in a population-based sample of healthy eyes. Methods:490 Chinese adults aged 40 to 80 years were recruited from the Singapore Chinese Eye Study. All participants underwent a comprehensive eye examination and a standardized interview. SD-OCT (Cirrus HD-OCT, software version 6.0, Carl Zeiss Meditec, Dublin, CA) measured a range of macular thickness parameters (central foveal subfield thickness, average inner macular thickness, average outer macular thickness, overall average macular thickness and overall macular cube volume). Linear regression analyses were performed to examine the effects of various ocular ...

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    1-25 of 25
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    Determinants of Macular Thickness using Spectral Domain Optical Coherence Tomography in Healthy Eyes: the Singapore Chinese Eye Study Sectoral variations of iridocorneal angle width and iris volume in Chinese Singaporeans: a swept-source optical coherence tomography study A Simplified Method to Measure Choroidal Thickness Using Adaptive Compensation in Enhanced Depth Imaging Optical Coherence Tomography Determinants of Optical Coherence Tomography–Derived Minimum Neuroretinal Rim Width in a Normal Chinese Population Relationship of ocular and systemic factors to the visibility of choroidal–scleral interface using spectral domain optical coherence tomography Automatic Feature Extraction of Optical Coherence Tomography for Lamina Cribrosa Detection Association of iris surface features with iris parameters assessed by swept-source optical coherence tomography in Asian eyes A Digital Staining Algorithm for Optical Coherence Tomography Images of the Optic Nerve Head Detailed Phenotyping and Characterization of Choroidal Morphological and Vascular Features in Young Men with High Myopia Using Spectral-Domain Optical Coherence Tomography Factors affecting signal strength in spectral-domain optical coherence tomography New insights from non-invasive imaging: from prospection of skin photodamages to training with mobile application Short-sighted woman assumes debilitating headaches mean she needs new glasses but discovers she has multiple sclerosis