1. Articles from Lisandro M. Sakata

    1-14 of 14
    1. 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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    2. 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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    3. Relationship Between Intraocular Pressure and Angle Configuration: An Anterior Segment OCT Study

      Relationship Between Intraocular Pressure and Angle Configuration: An Anterior Segment OCT Study

      Purpose: To assess the relationship between intra-ocular pressure (IOP) and anterior chamber angle (ACA) configuration as assessed by gonioscopy and anterior segment optical coherence tomography (AS-OCT). Methods: 2045 subjects aged 50 years and over, recruited from a community clinic, underwent AS-OCT, Goldmann applanation tonometry, and gonioscopy. A quadrant was classified as closed on gonioscopy if the posterior trabecular meshwork could not be seen. A closed quadrant on AS-OCT was defined by the presence of any contact between the iris and angle wall anterior to the scleral spur. Customized software (Zhongshan Angle Assessment Program, Guangzhou, China) was used to measure AS-OCT ...

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    4. 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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    5. 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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    6. 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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    7. 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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    8. 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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    9. Comparison of Slitlamp Optical Coherence Tomography and Scanning Peripheral Anterior Chamber Depth Analyzer to Evaluate Angle Closure in Asian Eyes

      Objective To evaluate the effectiveness of slitlamp optical coherence tomography (SL-OCT) and Scanning Peripheral Anterior Chamber depth analyzer (SPAC) in detecting angle closure, using gonioscopy as the reference standard. Methods A total of 153 subjects underwent gonioscopy, SL-OCT, and SPAC. The anterior chamber angle (ACA) was classified as closed on gonioscopy if the posterior trabecular meshwork could not be seen; with SL-OCT, closure was determined by contact between the iris and angle wall anterior to the scleral spur; and with SPAC by a numerical grade of 5 or fewer and/or a categorical grade of suspect or potential. Results A ...
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    10. Optical coherence tomography of the retina and optic nerve – a review

      Optical coherence tomography (OCT) is a rapid non-contact method that allows in vivo imaging of the retina, optic nerve head and retinal nerve fibre layer (RNFL). Since its introduction in Ophthalmology approximately a decade ago, the use of this technology has disseminated into the clinical practice. OCT has proven to be a useful ancillary tool for assessing retinal diseases because of its capability to provide cross-sectional images of the retina, and also to perform quantitative analysis of retinal morphology. In glaucoma, the OCT represents one of the methods capable of documenting and analysing optic disc and RNFL morphology in attempt ...
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    11. 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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    12. 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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    13. 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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    14. 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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    1-14 of 14
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    1. (13 articles) Tin Aung
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