1. Articles from Harry A. Quigley

    1-10 of 10
    1. In Vivo Characterization of the Deformation of the Human Optic Nerve Head Using Optical Coherence Tomography and Digital Volume Correlation

      In Vivo Characterization of the Deformation of the Human Optic Nerve Head Using Optical Coherence Tomography and Digital Volume Correlation

      We developed a method to measure the 3-dimensional (3D) strain field in the optic nerve head (ONH) in vivo between two intraocular pressures (IOP). Radial optical coherence tomography (OCT) scans were taken of the ONH of 5 eyes from 5 glaucoma patients before and after IOP-lowering surgery and from 5 eyes from 3 glaucoma suspect patients before and after raising IOP by wearing tight-fitting swimming goggles. Scans taken at higher and lower IOP were compared using a custom digital volume correlation (DVC) algorithm to calculate strains in the anterior lamina cribrosa (ALC), retina, and choroid. Changes in anterior lamina depth ...

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    2. 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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    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. Detection of Age-Related Macular Degeneration by Portable Optical Coherence Tomography Operated by Nonexpert Personnel: Potential Use for Screenings

      Detection of Age-Related Macular Degeneration by Portable Optical Coherence Tomography Operated by Nonexpert Personnel: Potential Use for Screenings

      Purpose: The purpose of this study is to determine the sensitivity and specificity of detecting age-related macular degeneration (AMD) using portable optical coherence tomography (OCT) operated by nonexpert photographers on undilated patients. Methods: In this case-control study, 92 individuals were recruited from the glaucoma and retina clinics at the Wilmer Eye Institute (Johns Hopkins University, Baltimore, MD). Using the portable iVue (Optovue, Inc, Fremont, CA) spectral-domain OCT (SD-OCT), 2 nonexpert photographers acquired retina map scans on undilated eyes of all participants. In total, 33 AMD eyes and 105 control eyes were evaluated and graded by ophthalmologists masked to the diagnoses ...

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    5. Evaluation of Automated Segmentation Algorithms for Optic Nerve Head Structures in Optical Coherence Tomography Images

      Evaluation of Automated Segmentation Algorithms for Optic Nerve Head Structures in Optical Coherence Tomography Images

      Purpose : To compare the identification of optic nerve head (ONH) structures in optical coherence tomography images by observers and automated algorithms. Methods : ONH images in 24 radial scan sets by optical coherence tomography were obtained in 51 eyes of 29 glaucoma patients and suspects. Masked intraobserver and interobserver comparisons were made of marked endpoints of Bruch's membrane opening (BMO) and the anterior lamina cribrosa (LC). BMO and LC positional markings were compared between observer and automated algorithm. Repeated analysis on 20 eyes by the algorithm was compared. Regional ONH data were derived from the algorithms. Results : Intraobserver difference in ...

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    6. Author Response: Biomechanical Responses of Lamina Cribrosa to Intraocular Pressure Change Assessed by Optical Coherence Tomography in Glaucoma Eyes

      Author Response: Biomechanical Responses of Lamina Cribrosa to Intraocular Pressure Change Assessed by Optical Coherence Tomography in Glaucoma Eyes

      Our recent publication 1 noted several features of change in anterior lamina depth (ALD) with change in intraocular pressure (IOP) in glaucoma patients. ALD changed more in the lower ranges of IOP than at higher ranges, which represents the expected increased stiffening of biomaterials in regions of higher stress. Some eyes exhibited movement of the lamina out of the eye at lower IOP—a behavior that is more likely when the peripapillary sclera is more compliant. This was more common in eyes with less glaucoma damage. The regions of the lamina that moved more were in its vertical poles, above ...

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    7. Comparison of Dynamic Changes in Anterior Ocular Structures Examined with Anterior Segment Optical Coherence Tomography in a Cohort of Various Origins

      Comparison of Dynamic Changes in Anterior Ocular Structures Examined with Anterior Segment Optical Coherence Tomography in a Cohort of Various Origins

      Purpose: To identify risk factors for angle closure from iris and angle anterior segment optical coherence tomography (ASOCT) measurements and to determine if these differ by geographic origin. Methods: ASOCT images from 267 clinic-based persons were compared between bright and dark conditions. An automated program quantified angle and iris parameters. Results: Iris area in bright light was larger with increasing age (univariate regression, p=0.0005), and largest in European and African-derived and smallest in Korean and Chinese eyes (multivariable regression, p=0.0001). Iris area was significantly larger in AC groups compared to normal and open angle glaucoma groups ...

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    8. The Effect of Scleral Spur Identification Methods on Structural Measurements by Anterior Segment Optical Coherence Tomography

      The Effect of Scleral Spur Identification Methods on Structural Measurements by Anterior Segment Optical Coherence Tomography

      Purpose: To assess methods for and variations in identifying the scleral spur (SS) position in anterior segment optical coherence tomography. Methods: In images of 51 eyes (patients) with open and closed anterior chamber angles, we compared the success rate and the variability of 3 approaches for identifying the SS: the ciliary muscle (CM), bump, and Schwalbe line (SL) methods using mixed effects regression models. The effect of incremental variation in SS position on anterior chamber parameters using the Anterior Segment Analysis Program (ASAP) was analyzed in 8 images. Automated ASAP measurements were compared with manual ImageJ measurements in 46 images ...

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    9. Choroidal Thickness Change after Water Drinking Is Greater in Angle Closure than in Open Angle Eyes [Glaucoma]

      Choroidal Thickness Change after Water Drinking Is Greater in Angle Closure than in Open Angle Eyes [Glaucoma]

      Purpose. To study change in choroidal thickness (CT) after water drinking test (WDT), comparing angle closure (AC) to open angle (OA) eyes.

      Methods. Before and 30 minutes after drinking 1 L of water, 88 glaucoma subjects underwent measurements of CT by spectral domain-optical coherence tomography, IOP, blood pressure (BP), axial length (AL), and anterior chamber depth (ACD).

      Results. Baseline CT was significantly greater in AC than in OA eyes (P = 0.002). After WDT, BP, IOP, and AL increased significantly (all P ≤ 0.0001). Mean CT increased significantly in the AC group (5.6 μm, P = 0.04, n = 40 ...

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    10. 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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    1-10 of 10
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    1. (10 articles) Johns Hopkins University
    2. (2 articles) Devers Eye Institute
    3. (2 articles) University of Alabama
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    6. (2 articles) Jeffrey M. Liebmann
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    Choroidal Thickness Measured by Spectral Domain Optical Coherence Tomography: Factors Affecting Thickness in Glaucoma Patients Choroidal Thickness Change after Water Drinking Is Greater in Angle Closure than in Open Angle Eyes [Glaucoma] The Effect of Scleral Spur Identification Methods on Structural Measurements by Anterior Segment Optical Coherence Tomography Comparison of Dynamic Changes in Anterior Ocular Structures Examined with Anterior Segment Optical Coherence Tomography in a Cohort of Various Origins Author Response: Biomechanical Responses of Lamina Cribrosa to Intraocular Pressure Change Assessed by Optical Coherence Tomography in Glaucoma Eyes Evaluation of Automated Segmentation Algorithms for Optic Nerve Head Structures in Optical Coherence Tomography Images Detection of Age-Related Macular Degeneration by Portable Optical Coherence Tomography Operated by Nonexpert Personnel: Potential Use for Screenings Factors Influencing Optical Coherence Tomography Peripapillary Choroidal Thickness: A Multicenter Study OCT-Detected Optic Nerve Head Neural Canal Direction, Obliqueness and Minimum Cross-Sectional Area in Healthy Eyes In Vivo Characterization of the Deformation of the Human Optic Nerve Head Using Optical Coherence Tomography and Digital Volume Correlation RAG-FW: A hybrid convolutional framework for the automated extraction of retinal lesions and lesion-influenced grading of human retinal pathology Self-aligned micro-optic integrated photonic platform