1. Articles from David S. Friedman

    1-25 of 25
    1. Glaucoma screening: where are we and where do we need to go?

      Glaucoma screening: where are we and where do we need to go?

      Purpose of review Current recommendations for glaucoma screening are decidedly neutral. No studies have yet documented improved long-term outcomes for individuals who undergo glaucoma screening versus those who do not. Given the long duration that would be required to detect a benefit, future studies that may answer this question definitively are unlikely. Nevertheless, advances in artificial intelligence and telemedicine will lead to more effective screening at lower cost. With these new technologies, additional research is needed to determine the costs and benefits of screening for glaucoma . Recent findings Using optic disc photographs and/or optical coherence tomography, deep learning systems ...

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    2. Understanding diagnostic disagreement in angle closure assessment between anterior segment optical coherence tomography and gonioscopy

      Understanding diagnostic disagreement in angle closure assessment between anterior segment optical coherence tomography and gonioscopy

      Background/aims Although being a more objective tool for assessment and follow-up of angle closure, reliability studies have reported a moderate diagnostic performance for anterior segment optical coherence tomography (OCT) technologies when comparing with gonioscopy as the reference standard. We aim to determine factors associated with diagnostic disagreement in angle closure when assessed by anterior segment swept source OCT (SS-OCT, CASIA SS-1000; Tomey, Nagoya, Japan) and gonioscopy. Methods Cross-sectional study. A total of 2027 phakic subjects aged ≥50 years, with no relevant previous ophthalmic history, were consecutively recruited from a community polyclinic in Singapore. Gonioscopy and SS-OCT (128 radial scans ...

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    3. 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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    4. Development of a Score and Probability Estimate for Detecting Angle Closure Based on Anterior Segment Optical Coherence Tomography

      Development of a Score and Probability Estimate for Detecting Angle Closure Based on Anterior Segment Optical Coherence Tomography

      Purpose To develop a score along with an estimated probability of disease for detecting angle closure based on anterior segment optical coherence tomography (AS OCT) imaging. Design Cross-sectional study. Methods A total of 2047 subjects 50 years of age and older were recruited from a community polyclinic in Singapore. All subjects underwent standardized ocular examination including gonioscopy and imaging by AS OCT (Carl Zeiss Meditec). Customized software (Zhongshan Angle Assessment Program) was used to measure AS OCT parameters. Complete data were available for 1368 subjects. Data from the right eyes were used for analysis. A stepwise logistic regression model with ...

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    5. Subgrouping of Primary Angle-Closure Suspects Based on Anterior Segment Optical Coherence Tomography Parameters

      Subgrouping of Primary Angle-Closure Suspects Based on Anterior Segment Optical Coherence Tomography Parameters

      Purpose To identify subgroups of primary angle-closure suspects (PACS) based on anterior segment optical coherence tomography (AS-OCT) and biometric parameters. Design Cross-sectional study. Participants We evaluated 243 PACS subjects in the primary group and 165 subjects in the validation group. Methods Participants underwent gonioscopy and AS-OCT (Carl Zeiss Meditec, Dublin, CA). Customized software (Zhongshan Angle Assessment Program, Guangzhou, China) was used to measure AS-OCT parameters. An agglomerative hierarchical clustering method was first used to determine the optimum number of parameters to be included in the determination of subgroups. The best number of subgroups was then determined using Akaike Information Criterion ...

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    6. Assessment of Circumferential Angle-Closure by the Iris–Trabecular Contact Index with Swept-Source Optical Coherence Tomography

      Assessment of Circumferential Angle-Closure by the Iris–Trabecular Contact Index with Swept-Source Optical Coherence Tomography

      Purpose To evaluate the diagnostic performance 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) in comparison with gonioscopy. Design Prospective observational study. Participants A total of 108 normal subjects and 32 subjects with angle-closure. Methods The SSOCT 3-dimensional angle scans, which obtain radial scans for the entire circumference of the angle, were performed under dark conditions and analyzed using customized software by a single examiner masked to the subjects' clinical details. The ITC index was calculated as a percentage of the angle ...

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    7. 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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    8. 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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    9. Classification Algorithms Based on Anterior Segment Optical Coherence Tomography Measurements for Detection of Angle Closure

      Classification Algorithms Based on Anterior Segment Optical Coherence Tomography Measurements for Detection of Angle Closure

      Objective: A recent study found that a combination of 6 anterior segment optical coherence tomography (ASOCT) parameters (anterior chamber area, volume, and width [ACA, ACV, ACW], lens vault [LV], iris thickness at 750 μm from the scleral spur, and iris cross-sectional area) explain >80% of the variability in angle width. The aim of this study was to evaluate classification algorithms based on ASOCT measurements for the detection of gonioscopic angle closure.Design: Cross-sectional study.Participants: We included 2047 subjects aged ≥50 years.Methods: Participants underwent gonioscopy and ASOCT (Carl Zeiss Meditec, Dublin, CA). Customized software (Zhongshan Angle Assessment Program, Guangzhou ...

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    10. 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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    11. Comparison of EyeCam and anterior segment optical coherence tomography in detecting angle closure

      Comparison of EyeCam and anterior segment optical coherence tomography in detecting angle closure

      Purpose:  To compare the diagnostic performance of EyeCam (Clarity Medical Systems, Pleasanton, CA, USA) and anterior segment optical coherence tomography (ASOCT, Visante; Carl Zeiss Meditec, Dublin, CA, USA) in detecting angle closure, using gonioscopy as the reference standard. Methods:  Ninety-eight phakic patients, recruited from a glaucoma clinic, underwent gonioscopy by a single examiner, and EyeCam and ASOCT imaging by another examiner. Another observer, masked to gonioscopy findings, graded EyeCam and ASOCT images. For both gonioscopy and EyeCam, a closed angle in a particular quadrant was defined if the posterior trabecular meshwork was not visible. For ASOCT, angle closure was defined ...

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    12. Changes in Anterior Segment Morphology after Laser Peripheral Iridotomy: An Anterior Segment Optical Coherence Tomography Study

      Changes in Anterior Segment Morphology after Laser Peripheral Iridotomy: An Anterior Segment Optical Coherence Tomography Study

      Purpose Novel anterior segment optical coherence tomography (ASOCT) parameters associated with angle closure include anterior chamber area (ACA), anterior chamber volume (ACV), anterior chamber width (ACW), lens vault (LV), iris thickness (IT), iris area (I-area), and iris curvature (I-curv). We aimed to investigate changes in these parameters after laser peripheral iridotomy (LPI) in a cohort of primary angle-closure suspects (PACS). Design Prospective observational study. Participants and Controls A total of 176 PACS aged ≥50 years who underwent LPI in 1 eye. Methods We analyzed ASOCT images (Visante, Carl Zeiss Meditec, Dublin, CA) from all subjects using customized software before and ...

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    13. Association of Narrow Angles With Anterior Chamber Area and Volume Measured With Anterior-Segment Optical Coherence Tomography]

      Association of Narrow Angles With Anterior Chamber Area and Volume Measured With Anterior-Segment Optical Coherence Tomography]
      Objectives To describe the measurement of anterior chamber area and anterior chamber volume by anterior-segment optical coherence tomography and to investigate the association of these parameters with the presence of narrow angles. Methods This was a cross-sectional study of subjects aged at least 50 years without ophthalmic symptoms recruited from a community clinic. All participants underwent standardized ocular examination and anterior-segment optical coherence tomography. Customized software was used to measure anterior chamber area (cross-sectional area bounded by the corneal endothelium, anterior surface of iris, and lens within the pupil) and anterior chamber volume (calculated by rotating the anterior chamber area ...
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    14. Choroidal Thickness Measured by Spectral Domain Optical Coherence Tomography: Factors Affecting Thickness in Glaucoma Patients

      Choroidal Thickness Measured by Spectral Domain Optical Coherence Tomography: Factors Affecting Thickness in Glaucoma Patients
      Purpose: To measure choroidal thickness and to determine parameters associated with it.Design: Cross-sectional study.Participants: Seventy-four glaucoma patients and glaucoma suspects.Methods: Spectral domain optical coherence tomography (SD-OCT) scans were obtained to estimate average choroidal thickness in a group of glaucoma suspects and glaucoma patients. The average thickness was calculated from enhanced depth SD-OCT images and manually analyzed with Image J software. Open-angle glaucoma, open-angle glaucoma suspect, primary angle-closure glaucoma, primary angle closure, and primary angle-closure suspect were defined by published criteria. Glaucoma suspects had normal visual fields bilaterally. Glaucoma was defined by specific criteria for optic disc damage ...
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    15. Single versus sequential testing with scanning peripheral anterior chamber depth analyser, IOLMaster and anterior segment optical coherence tomography for the detection of narrow angles

      Single versus sequential testing with scanning peripheral anterior chamber depth analyser, IOLMaster and anterior segment optical coherence tomography for the detection of narrow angles
      Background Scanning peripheral anterior chamber depth analyser (SPAC), IOLMaster and anterior segment optical coherence tomography (AS-OCT) are devices that can screen non-invasively for narrow angles (NAs) and may reduce the need for gonioscopy, especially where the availability of ophthalmologists is limited. When used individually to detect NAs, neither SPAC, AS-OCT nor IOLMaster were able to achieve both high sensitivity and specificity when using gonioscopy as a gold standard. Aims To assess whether sequential testing improves discrimination of NAs over single testing. Methods In a prospective community-based cross-sectional study in Singapore, 2047 phakic right eyes underwent SPAC, IOLMaster and AS-OCT. NA ...
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    16. Diagnostic Performance of Anterior Chamber Angle Measurements for Detecting Eyes With Narrow Angles: An Anterior Segment OCT Study: An Anterior Segment OCT Study

      Diagnostic Performance of Anterior Chamber Angle Measurements for Detecting Eyes With Narrow Angles: An Anterior Segment OCT Study: An Anterior Segment OCT Study

      Objective  To assess the diagnostic performance of angle measurements from anterior segment optical coherence tomography (AS-OCT) images for identifying eyes with narrow angles. Methods  We conducted a community-based cross-sectional study of individuals 50 years or older who had phakic eyes and who underwent AS-OCT imaging in the dark by a single operator and gonioscopy by an ophthalmologist masked to AS-OCT findings. An eye was considered to have narrow angles if the posterior pigmented trabecular meshwork was not visible for at least 180° on gonioscopy. Horizontal AS-OCT images were analyzed for the following measurements using customized software: angle opening distance (AOD ...

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    17. Normal Macular Thickness Measurements Using Optical Coherence Tomography in Healthy Eyes of Adult Chinese Persons: The Handan Eye Study

      Normal Macular Thickness Measurements Using Optical Coherence Tomography in Healthy Eyes of Adult Chinese Persons: The Handan Eye Study

      Purpose: To describe macular thickness measured by optical coherence tomography (OCT) in healthy eyes of adult Chinese persons.Design: Population-based cross-sectional study.Participants: Chinese adults aged 30+ years who were residents of Handan, North China.Methods: The Handan Eye Study is a population-based study of eye disease in Chinese persons. Eligible residents underwent a comprehensive ophthalmic examination including OCT (Stratus OCT, Carl Zeiss Meditec Inc., Jena, Germany). Fast macular thickness scans were performed over maculae within 6 mm in diameter, divided into 3 regions (central, inner, and outer, with a diameter of 1, 3, and 6 mm, respectively) and 9 ...

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    18. Evaluation of Scanning Protocols for Imaging the Anterior Chamber Angle With Anterior Segment-Optical Coherence Tomography

      Purpose: To evaluate different anterior segment-optical coherence tomography (AS-OCT) scanning protocols for detecting eyes with angle closure. Methods: This cross-sectional study enrolled 2104 subjects from a community clinic in Singapore. All participants underwent AS-OCT imaging in the dark (Visante, Carl-Zeiss, Meditec, Dublin, CA), and gonioscopy with a Goldmann 2-mirror and a Sussman lens by an experienced examiner. The anterior chamber angle in a particular quadrant was considered closed on gonioscopy if the posterior trabecular meshwork could not be seen; and on AS-OCT by the presence of contact between the iris and angle wall anterior to the scleral spur. Protocols using ...
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    19. High-Definition Optical Coherence Tomography Imaging of the Iridocorneal Angle of the Eye

      Objective To assess the ability of high-definition optical coherence tomography (HD-OCT) to image the anterior chamber angle. Methods Forty-five consecutive subjects with phakic eyes underwent gonioscopy and anterior chamber angle imaging with HD-OCT adapted with a 60-diopter aspheric lens mounted over the imaging aperture. The patients' fixation was directed to the side using an external fixation light, and scans were taken of the temporal and nasal quadrants. The visibility of angle structures was assessed and the diagnosis of angle closure using HD-OCT was compared with that of gonioscopy. Results The majority of subjects were Chinese (91.1%) and female (62 ...
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    20. Screening for Narrow Angles in the Singapore Population: Evaluation of New Noncontact Screening Methods

      Purpose: To assess the screening effectiveness of 3 new noncontact devices, the scanning peripheral anterior chamber depth analyzer (SPAC) (Takagi, Nagano, Japan), which measures peripheral anterior chamber depth (ACD); IOLMaster (Carl Zeiss Meditec, Jena, Germany), which measures central ACD; and Visante anterior segment optical coherence tomography (AS-OCT) (Visante, Carl Zeiss Meditec, Dublin, CA), which images the angles, and to compare these instruments with gonioscopy in identifying people with narrow angles (NAs).Design: Cross-sectional, observational, community-based study.Participants: Phakic subjects aged ≥50 years without ophthalmic symptoms who were recruited from a community polyclinic in Singapore.Methods: All subjects underwent examination with ...

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    21. 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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    22. Quantitative Analysis of Anterior Segment Optical Coherence Tomography Images: the Zhongshan Angle Assessment Program

      Purpose: To describe a new image analysis method and software for anterior chamber images obtained by the anterior-segment optical coherence tomography (AS-OCT).and to assess its intraobserver and interobserver measurement reproducibility. Methods: Twenty 8-bit grayscale 600 x 300 AS-OCT images with apparent wide angles and twenty images with apparent narrow angles were consecutively selected from a database. Two glaucoma fellowship-trained ophthalmologists used proprietary image analysis software to analyze the images twice. Algorithms defined the borders and curvatures of anterior chamber (AC) structures and measured AC parameters using scleral spur location as the only observer input. Intraobserver and interobserver reproducibility of ...
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    23. Anterior Chamber Angle Assessment Techniques

      Angle-closure glaucoma is a leading cause of irreversible blindness. Diagnosis and treatment are intricately related to angle assessment techniques. This article reviews the literature on angle assessment and provides recommendations about optimal techniques based on the published evidence. Specifically, we review gonioscopy, ultrasound biomicroscopy, and anterior segment optical coherence tomography, all of which can be used to assess the anterior chamber angle directly. In addition, we discuss surrogate approaches to measuring the angle configuration, including limbal anterior chamber depth measurement, scanning peripheral anterior chamber depth measurement, and Scheimpflug photography.
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    24. Assessment of the Scleral Spur in Anterior Segment Optical Coherence Tomography Images

      Objective  To assess visibility of the scleral spur in anterior segment optical coherence tomography (AS-OCT) images. Methods  This cross-sectional observational study included 502 participants aged 50 years or older who had no previous ophthalmic problems and were recruited from a community clinic in Singapore. All participants underwent gonioscopy and AS-OCT (Visante; Carl Zeiss Meditec, Dublin, California). Scleral spur location was assessed in AS-OCT images by 2 examiners with glaucoma subspecialty training and was defined as the point where there was an inward protrusion of the sclera with a change in curvature of its inner surface. Results  Scleral spur location could ...

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    25. 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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    1-25 of 25
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    1. (24 articles) David S. Friedman
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    Normal Macular Thickness Measurements Using Optical Coherence Tomography in Healthy Eyes of Adult Chinese Persons: The Handan Eye Study Diagnostic Performance of Anterior Chamber Angle Measurements for Detecting Eyes With Narrow Angles: An Anterior Segment OCT Study: An Anterior Segment OCT Study Choroidal Thickness Measured by Spectral Domain Optical Coherence Tomography: Factors Affecting Thickness in Glaucoma Patients Association of Narrow Angles With Anterior Chamber Area and Volume Measured With Anterior-Segment Optical Coherence Tomography] Medical treatment of inflammatory punctual stenosis monitored by anterior segment optical coherence tomography Development and Validation of a Deep Learning System for Diagnosing Glaucoma Using Optical Coherence Tomography Methylene blue-filled biodegradable polymer particles as a contrast agent for optical coherence tomography Optical coherence tomography for thyroid pathology: 3D analysis of tissue microstructure Mathematical Analysis of Texture Indicators for the Segmentation of Optical Coherence Tomography Images Comparison of Current Optical Coherence Tomography Angiography Methods in Imaging Retinal Hemangioblastomas New findings useful for clinical practice using swept-source optical coherence tomography angiography in the follow-up of active ocular toxoplasmosis Comparison of two measurements for the lower lid margin thickness: vernier micrometer and anterior segment optical coherence tomography