1. Articles from balwantray c. chauhan

    1-13 of 13
    1. OCT-Detected Optic Nerve Head Neural Canal Direction, Obliqueness and Minimum Cross-Sectional Area in Healthy Eyes

      OCT-Detected Optic Nerve Head Neural Canal Direction, Obliqueness and Minimum Cross-Sectional Area in Healthy Eyes

      Purpose To assess anterior scleral canal opening (ASCO) offset relative to Bruch’s membrane opening (BMO) (ASCO/BMO offset) so as to determine neural canal direction, obliqueness, and minimum cross-sectional area (NCMCA) in 362 healthy eyes. Design Cross-sectional study Methods After OCT optic nerve head (ONH) and retinal nerve fiber layer thickness (RNFLT) imaging, BMO and ASCO were manually segmented and planes, centroids, size and shape were calculated. Neural canal direction was defined by projecting the neural canal axis vector (connecting BMO and ASCO centroids) onto the BMO plane. Neural canal obliqueness was defined by the angle between the neural ...

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    2. Optical Coherence Tomography Angiography in Mice: Quantitative Analysis After Experimental Models of Retinal Damage

      Optical Coherence Tomography Angiography in Mice: Quantitative Analysis After Experimental Models of Retinal Damage

      Purpose : We implemented optical coherence tomography angiography (OCT-A) in mice to: (1) develop quantitative parameters from OCT-A images, (2) measure the reproducibility of the parameters, and (3) determine the impact of experimental models of inner and outer retinal damage on OCT-A findings. Methods : OCT-A images were acquired with a customized system (Spectralis Multiline OCT2). To assess reproducibility, imaging was performed five times over 1 month. Inner retinal damage was induced with optic nerve transection, crush, or intravitreal N -methyl-d-aspartic acid injection in transgenic mice with fluorescently labeled retinal ganglion cells (RGCs). Light-induced retinal damage was induced in albino mice. Mice ...

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    3. Factors Influencing Optical Coherence Tomography Peripapillary Choroidal Thickness: A Multicenter Study

      Factors Influencing Optical Coherence Tomography Peripapillary Choroidal Thickness: A Multicenter Study

      Purpose : To quantify peripapillary choroidal thickness (PCT) and the factors that influence it in healthy participants who represent the racial and ethnic composition of the U.S. population. Methods : A total of 362 healthy participants underwent optical coherence tomography (OCT) enhanced depth imaging of the optic nerve head with a 24 radial B-scan pattern aligned to the fovea to Bruch's membrane opening axis. Bruch's membrane, anterior scleral canal opening (ASCO), and the anterior scleral surface were manually segmented. PCT was measured at 100, 300, 500, 700, 900, and 1100 μm from the ASCO globally and within 12 clock-hour ...

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    4. Impact of Head Tilt on Optical Coherence Tomography Image Orientation

      Impact of Head Tilt on Optical Coherence Tomography Image Orientation

      Purpose: Head tilt can have an impact on the orientation of posterior pole images. We conducted this study to determine the effect of head tilt on image orientation measured by the fovea - Bruch’s membrane opening (FoBMO) angle with optical coherence tomography (OCT) imaging. Methods: The study included 56 healthy subjects with mean (range) age of 33 (18-61) years. The dominant eye was first determined. To measure head tilt , a smartphone with a built-in gyroscope was affixed to the subject’s head with adjustable straps. OCT (Spectralis, Heidelberg Engineering) imaging was performed in both eyes (in randomized order) at 0 ...

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    5. Visibility of Optic Nerve Head Structures With Spectral-domain and Swept-source Optical Coherence Tomography

      Visibility of Optic Nerve Head Structures With Spectral-domain and Swept-source Optical Coherence Tomography

      Purpose: To compare the visibility of deep optic nerve head (ONH) structures and the visible area of the anterior surface of the lamina cribrosa (ASLC) with spectral-domain optical coherence tomography (SD-OCT) and swept-source OCT (SS-OCT). Materials and Methods: In total, 33 glaucoma patients were imaged with SD-OCT (Spectralis, 24 radial B-scans centered on the ONH) and SS-OCT (Atlantis, 12 radial and a horizontal and vertical raster scan pattern containing 5 lines each, centered on the ONH). One of the SS-OCT horizontal and vertical scans that was best matching with the horizontal and vertical scan lines with those of SD-OCT was ...

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    6. Diagnostic Accuracy of Optical Coherence Tomography and Scanning Laser Tomography for Identifying Glaucoma in Myopic Eyes

      Diagnostic Accuracy of Optical Coherence Tomography and Scanning Laser Tomography for Identifying Glaucoma in Myopic Eyes

      Purpose Ruling out glaucoma in myopic eyes often poses a diagnostic challenge because of atypical optic disc morphology and visual field defects that can mimic glaucoma. We determined whether neuroretinal rim assessment based on Bruch's membrane opening (BMO), rather than conventional optic disc margin (DM)-based assessment or retinal nerve fiber layer (RNFL) thickness, yielded higher diagnostic accuracy in myopic patients with glaucoma. Design Case-control, cross-sectional study. Participants Myopic patients with glaucoma (n = 56) and myopic normal controls (n = 74). Methods Myopic subjects with refraction error greater than −2 diopters (D) (spherical equivalent) and typical myopic optic disc morphology ...

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    7. Imaging of the Temporal Raphe with Optical Coherence Tomography

      Imaging of the Temporal Raphe with Optical Coherence Tomography

      There has been considerable debate about the arrangement and composition of the temporal raphe in the human retina. In postmortem studies, Vrabec 1 showed that axons of retinal ganglion cells temporal to the fovea are forced to take an arched course above and below the papillomacular bundle and that the temporal raphe generally represents a watershed midline. However, there is scarce published literature on the relationship between the orientation of the papillomacular bundle and the temporal raphe.

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    8. Automated Segmentation of Optic Nerve Head Structures with Optical Coherence Tomography

      Automated Segmentation of Optic Nerve Head Structures with Optical Coherence Tomography

      Purpose: To quantify and characterise the difference between automated and manual segmentation of optic nerve head structures with spectral domain-optical coherence tomography (SD-OCT). Methods: Optic nerve head radial scans in 107 glaucoma patients and 48 healthy controls were conducted with SD-OCT. Independent segmentations of the internal limiting membrane (ILM) and Bruch's membrane opening (BMO) were performed manually with custom software and with an automated algorithm in each radial scan. The minimum distance between BMO and ILM, termed BMO-minimum rim width (BMO-MRW) was calculated with each segmentation method. Absolute differences between automated and manual segmentations of ILM (ΔILM) and BMO ...

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    9. Enhanced Detection of Open-angle Glaucoma with an Anatomically Accurate Optical Coherence Tomography–Derived Neuroretinal Rim Parameter

      Enhanced Detection of Open-angle Glaucoma with an Anatomically Accurate Optical Coherence Tomography–Derived Neuroretinal Rim Parameter

      Objective Neuroretinal rim assessment based on the clinical optic disc margin (DM) lacks a sound anatomic basis for 2 reasons: (1) The DM is not reliable as the outer border of rim tissue because of clinically and photographically invisible extensions of Bruch's membrane (BM) inside the DM and (2) nonaccountability of rim tissue orientation in the optic nerve head (ONH). The BM opening-minimum rim width (BMO-MRW) is a parameter that quantifies the rim from its true anatomic outer border, BMO, and accounts for its variable orientation. We report the diagnostic capability of BMO-MRW. Design Case control. Participants Patients with ...

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    10. Laminar Displacement and Prelaminar Tissue Thickness Change after Glaucoma Surgery Imaged with Optical Coherence Tomography

      Laminar Displacement and Prelaminar Tissue Thickness Change after Glaucoma Surgery Imaged with Optical Coherence Tomography

      Purpose: To study changes in lamina cribrosa position and prelaminar tissue thickness (PTT) after surgical intraocular pressure (IOP) reduction in glaucoma patients. Methods: Twenty-two patients (mean age, 71.4 years) were imaged with spectral domain optical coherence tomography (SD-OCT, 24 radial B-scans centered on the optic nerve head) before trabeculectomy or tube shunt implantation. Follow-up images were acquired 1 week, 1 month, 3 and 6 months post-surgery. Bruch's membrane opening (BMO), the internal limiting membrane (ILM) and the anterior laminar surface (ALS) were segmented with custom software. Surfaces were fitted to the ILM and ALS with the extracted 3D ...

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    11. Optic Disc Margin Anatomy in Patients with Glaucoma and Normal Controls with Spectral Domain Optical Coherence Tomography

      Optic Disc Margin Anatomy in Patients with Glaucoma and Normal Controls with Spectral Domain Optical Coherence Tomography

      Objective To characterize optic nerve head (ONH) anatomy related to the clinical optic disc margin with spectral domain-optical coherence tomography (SD-OCT). Design Cross-sectional study. Participants Patients with open-angle glaucoma with focal, diffuse, and sclerotic optic disc damage, and age-matched normal controls. Methods High-resolution radial SD-OCT B-scans centered on the ONH were analyzed at each clock hour. For each scan, the border tissue of Elschnig was classified for obliqueness (internally oblique, externally oblique, or nonoblique) and the presence of Bruch's membrane overhanging the border tissue. Optic disc stereophotographs were co-localized to SD-OCT data with customized software. The frequency with which ...

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    12. Progressive Optic Disc Change: Implications for Clinical Practice and Trial Design

      Ocular hypertensive patients without convincing evidence of glaucomatous visual field defects with standard automated perimetry often present a dilemma for clinicians. After 5 years of follow-up the Ocular Hypertension Treatment Study showed that while reducing intraocular pressure (IOP) halved the relative risk of developing glaucoma (from 9.5% to 4.4%), the absolute risk reduction was only 5%, with around 90% of the subjects randomized to only observation not developing glaucoma.1 The Ocular Hypertension Treatment Study demonstrated the potent role of IOP in the development of glaucoma, yet it also highlighted that risk profiling for factors in addition to ...

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    13. Comparison between confocal scanning laser tomography, scanning laser polarimetry and optical coherence tomography on the ability to detect localized retinal nerve fiber layer defects in glaucoma patients

      Background/Aim: To compare the ability of confocal scanning laser tomography (CSLT), scanning laser polarimetry (SLP) and optical coherence tomography (OCT) in recognizing localized retinal nerve fiber layer (RNFL) defects. Methods: 51 eyes from 43 patients with glaucoma were identified by two observers as having RNFL defects visible on optic disc photographs. 51 eyes of 32 normal subjects were used as controls. Three masked observers evaluated CSLT, SLP and OCT images to determine subjectively the presence of localized RNFL defects. Results: Interobserver agreement was highest with OCT, followed by SLP and CSLT (mean kappa: 0.83, 0.69 and 0 ...

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    1-13 of 13
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  2. Topics in the News

    1. (12 articles) Balwantray C. Chauhan
    2. (11 articles) Dalhousie University
    3. (8 articles) Glen P. Sharpe
    4. (6 articles) Marcelo T. Nicolela
    5. (4 articles) Devers Eye Institute
    6. (4 articles) Claude F. Burgoyne
    7. (4 articles) Hongli Yang
    8. (3 articles) University of São Paulo
    9. (3 articles) Alexandre S. C. Reis
    10. (2 articles) University of Heidelberg
    11. (1 articles) Harvard University
    12. (1 articles) Massachusetts General Hospital
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    15. (1 articles) Robert A. Huber
    16. (1 articles) Gijs van Soest
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    Optic Disc Margin Anatomy in Patients with Glaucoma and Normal Controls with Spectral Domain Optical Coherence Tomography Laminar Displacement and Prelaminar Tissue Thickness Change after Glaucoma Surgery Imaged with Optical Coherence Tomography Enhanced Detection of Open-angle Glaucoma with an Anatomically Accurate Optical Coherence Tomography–Derived Neuroretinal Rim Parameter Automated Segmentation of Optic Nerve Head Structures with Optical Coherence Tomography Imaging of the Temporal Raphe with Optical Coherence Tomography Diagnostic Accuracy of Optical Coherence Tomography and Scanning Laser Tomography for Identifying Glaucoma in Myopic Eyes Visibility of Optic Nerve Head Structures With Spectral-domain and Swept-source Optical Coherence Tomography Impact of Head Tilt on Optical Coherence Tomography Image Orientation AI-Assisted In Situ Detection of Human Glioma Infiltration Using a Novel Computational Method for Optical Coherence Tomography Motorized capsule for shadow-free OCT imaging and synchronous beam control Notal Vision Diagnostic Clinic reports completion of 6 million ForeseeHome AMD home-monitoring tests Monitoring retinal responses to acute intraocular pressure elevation in rats with visible light optical coherence tomography