1. Christopher Bowd

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    1. Mentioned In 19 Articles

    2. Association of Macular and Circumpapillary Microvasculature with Visual Field Sensitivity in Advanced Glaucoma

      Association of Macular and Circumpapillary Microvasculature with Visual Field Sensitivity in Advanced Glaucoma
      Purpose To evaluate the association between optical coherence tomography angiography (OCTA) macular and circumpapillary vessel density and visual field mean deviation (MD) in advanced primary open angle glaucoma (POAG). Design Cross-sectional study. Methods Macula (superficial layer) and optic nerve head [ONH, with (capillary density :CD) and without (vessel density: VD) automated removal of large vessels] OCTA of 34 eyes (34 patients, MD -10 dB) were investigated as macula whole image ...
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    3. Measurement floors and dynamic ranges of optical coherence tomography and angiography in glaucoma

      Measurement floors and dynamic ranges of optical coherence tomography and angiography in glaucoma
      Purpose To determine if optical coherence tomography angiography (OCTA)derived vessel density measurements can extend the available dynamic range for detecting glaucoma compared to spectral-domain optical coherence tomography (SDOCT)derived thickness measurements. Design Observational, cross-sectional study. Participants A total of 509 eyes from 38 healthy participants, 63 glaucoma suspects and 193 glaucoma patients enrolled in the Diagnostic Innovations in Glaucoma Study. Methods Relative vessel density and tissue thickness measurement floors ...
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    4. Retinal Nerve Fiber Layer Features Identified by Unsupervised Machine Learning on Optical Coherence Tomography Scans Predict Glaucoma Progression

      Retinal Nerve Fiber Layer Features Identified by Unsupervised Machine Learning on Optical Coherence Tomography Scans Predict Glaucoma Progression
      Purpose : To apply computational techniques to wide-angle swept-source optical coherence tomography (SS-OCT) images to identify novel, glaucoma-related structural features and improve detection of glaucoma and prediction of future glaucomatous progression. Methods : Wide-angle SS-OCT, OCT circumpapillary retinal nerve fiber layer (cpRNFL) circle scans spectral-domain (SD)-OCT, standard automated perimetry (SAP), and frequency doubling technology (FDT) visual field tests were completed every 3 months for 2 years from a cohort of 28 ...
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    5. Comparing optical coherence tomography radial and cube scan patterns for measuring Bruch's membrane opening minimum rim width (BMO-MRW) in glaucoma and healthy eyes: cross-sectional and longitudinal analysis

      Comparing optical coherence tomography radial and cube scan patterns for measuring Bruch's membrane opening minimum rim width (BMO-MRW) in glaucoma and healthy eyes: cross-sectional and longitudinal analysis
      Aim To compare the cube and radial scan patterns of the spectral domain optical coherence tomography (SD-OCT) for quantifying the Bruch's membrane opening minimum rim width (BMO-MRW). Methods Sixty healthy eyes and 189 glaucomatous eyes were included. The optic nerve head cube and radial pattern scans were acquired using Spectralis SD-OCT. BMO-MRWs were automatically delineated using the San Diego Automated Layer Segmentation Algorithm. The BMO-MRW diagnostic accuracy for glaucoma ...
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    6. Estimating OCT Structural Measurement Floors to Improve Detection of Progression In Advanced Glaucoma

      Estimating OCT Structural Measurement Floors to Improve Detection of Progression In Advanced Glaucoma
      Purpose Floor effects in retinal imaging are defined as the points at which no further structural loss can be detected. We estimated the measurement floors for spectral-domain optical coherence tomography (SD-OCT) measurements and compared global change over time in advanced glaucoma eyes. Design Validity study to investigate measurement floors. Methods A longitudinal Variability Group of 41 eyes with moderate to advanced glaucoma (SAP MD -8 dB) was used to estimate ...
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    7. A hierarchical framework for estimating neuroretinal rim area using 3D spectral domain optical coherence tomography (SD-OCT) optic nerve head (ONH) images of healthy and glaucoma eyes

      A hierarchical framework for estimating neuroretinal rim area using 3D spectral domain optical coherence tomography (SD-OCT) optic nerve head (ONH) images of healthy and glaucoma eyes
      Glaucoma is a chronic neurodegenerative disease characterized by loss of retinal ganglion cells, resulting in distinctive changes in the optic nerve head (ONH) and retinal nerve fiber layer (RNFL). Important advances in technology for non-invasive imaging of the eye have been made providing quantitative tools to measure structural changes in ONH topography, a crucial step in diagnosing and monitoring glaucoma. 3D spectral domain optical coherence tomography (SD-OCT), an optical imaging ...
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    8. Pattern electroretinogram association with spectral domain-OCT structural measurements in glaucoma

      Pattern electroretinogram association with spectral domain-OCT structural measurements in glaucoma
      Purpose To describe the association between pattern electroretinogram (PERG) amplitude and spectral domain-optical coherence tomography (SD-OCT) macular thickness, retinal nerve fibre layer (RNFL) thickness and optic disc topography measurements. Subjects and methods Both eyes (n=132) of 66 glaucoma patients (mean age=67.9 years) enroled in the University of California, San Diego, CA, USA, Diagnostic Innovations in Glaucoma Study (DIGS) were included. Eyes were tested with PERG (Glaid PERGLA ...
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    9. Agreement Among Spectral-Domain Optical Coherence Tomography Instruments for Assessing Retinal Nerve Fiber Layer Thickness

      Agreement Among Spectral-Domain Optical Coherence Tomography Instruments for Assessing Retinal Nerve Fiber Layer Thickness
      Purpose:: To assess the agreement of parapapillary retinal nerve fiber layer (RNFL) thickness measurements among 3 spectral-domain optical coherence tomography (SD-OCT) instruments.Design:: Observational, cross-sectional study.Methods:: Three hundred thirty eyes (88 with glaucoma, 206 glaucoma suspects, 36 healthy) from 208 individuals enrolled in the Diagnostic Innovations in Glaucoma Study (DIGS) were imaged using RTVue, Spectralis and Cirrus in a single visit. Agreement among RNFL thickness measurements was assessed using ...
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    10. Agreement between spectral-domain and time-domain OCT for measuring RNFL thickness

      Background/aims: To evaluate spectral-domain (SD) optical coherence tomography (OCT) reproducibility and assess the agreement between SD-OCT and Time-Domain (TD) OCT retinal nerve fibre layer (RNFL) measurements. Methods: Three Cirrus-SD-OCT scans and one Stratus-TD-OCT scan were obtained from Diagnostic Innovations in Glaucoma Study (DIGS) healthy participants and glaucoma patients on the same day. Repeatability was evaluated using Sw (within-subject standard deviation), CV (coefficient of variation) and ICC (intraclass correlation coefficient ...
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    11. Effect of Signal Strength and Improper Alignment on the Variability of Stratus Optical Coherence Tomography Retinal Nerve Fiber Layer Thickness Measurements

      Purpose To evaluate the effect of signal strength and improper scan alignment on retinal nerve fiber layer (RNFL) thickness measurement variability. Design Retrospective, longitudinal clinical study. Methods All eyes of healthy subjects with at least 2 fast RNFL scan sessions were selected from the Diagnostic Innovations in Glaucoma Study. The chronological first scan was considered to be the baseline. Absolute differences in signal strength and RNFL thickness measurements between baseline ...
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    12. Reproducibility of RTVue Retinal Nerve Fiber Layer Thickness and Optic Disc Measurements and Agreement with Stratus Optical Coherence Tomography Measurements

      Purpose: To evaluate RTVue spectral-domain optical coherence tomography (OCT) (Optovue Inc, Fremont, California, USA) reproducibility and to assess agreement with Stratus time-domain OCT (Carl Zeiss Meditec, Dublin, California, USA) measurements.Design: Observational clinical study.Methods: Scans were obtained from both eyes of all participants 3 times using the RTVue nerve head map 4-mm diameter protocol and once using Stratus OCT within the same session. RTVue reproducibility and agreement with Stratus ...
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    13. 1-15 of 19 1 2 »
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  2. About Christopher Bowd

    Christopher Bowd

    Christoper Bowd is Associate Research Scientist at the Hamilton Glaucoma Center, Department of Ophthalmology, University of California, San Diego in La Jolla, Calif. His research interests include development and evaluation of optical imaging techniques for the early detection and monitoring of glaucoma, and machine learning classifier analysis of imaging and psychophysical testing data.