1. Masahiro Akiba

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    1. Mentioned In 24 Articles

    2. Repeatability and Reproducibility of Retinal Blood Flow Measurement Using a Doppler Optical Coherence Tomography Flowmeter in Healthy Subjects

      Repeatability and Reproducibility of Retinal Blood Flow Measurement Using a Doppler Optical Coherence Tomography Flowmeter in Healthy Subjects
      Purpose : To evaluate the repeatability and reproducibility of retinal blood flow (RBF) measurements in humans by using new auto-alignment and measurement software in a commercially available Doppler optical coherence tomography (DOCT) system. Methods : The DOCT flowmeter assessed the intrasession repeatability and the intersession and interobserver reproducibility of the RBF measurements. For intrasession repeatability, the coefficients of variation (CVs) of five repeated RBF measurements were calculated at the retinal arteries and ...
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    3. Speckle Reduction in 3D Optical Coherence Tomography of Retina by A-Scan Reconstruction

      Speckle Reduction in 3D Optical Coherence Tomography of Retina by A-Scan Reconstruction
      Optical coherence tomography (OCT) is a micrometer-scale, cross-sectional imaging modality for biological tissue. It has been widely used for retinal imaging in ophthalmology. Speckle noise is problematic in OCT. A raw OCT image/volume usually has very poor image quality due to speckle noise, which often obscures the retinal structures. Overlapping scan is often used for speckle reduction in a 2D line-scan. However, it leads to an increase of the ...
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    4. Clinical Factors Associated with Lamina Cribrosa Thickness in Patients with Glaucoma, as Measured with Swept Source Optical Coherence Tomography

      Clinical Factors Associated with Lamina Cribrosa Thickness in Patients with Glaucoma, as Measured with Swept Source Optical Coherence Tomography
      Purpose To investigate the influence of various risk factors on thinning of the lamina cribrosa (LC), as measured with swept-source optical coherence tomography (SS-OCT; Topcon). Methods This retrospective study comprised 150 eyes of 150 patients: 22 normal subjects, 28 preperimetric glaucoma (PPG) patients, and 100 open-angle glaucoma patients. Average LC thickness was determined in a 3 x 3 mm cube scan of the optic disc, over which a 4 x ...
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    5. Analysis of Peripapillary Geometric Characters in High Myopia Using Swept-Source Optical Coherence Tomography

      Analysis of Peripapillary Geometric Characters in High Myopia Using Swept-Source Optical Coherence Tomography
      Purpose : We measured the three-dimensional geometric profile around the optic nerve head (ONH) using swept-source optical coherence tomography (SS-OCT) in highly myopic eyes. Methods : We studied 114 highly myopic eyes (6.0 diopters [D]) of 114 patients without glaucoma. Eyes were examined using the prototype SS-OCT. The retinal pigment epithelium (RPE) and chorioscleral interface were traced, and the mean y -axis coordinates of 24 sectors were calculated in circular peripapillary ...
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    6. 3D Evaluation of the Lamina Cribrosa with Swept-Source Optical Coherence Tomography in Normal Tension Glaucoma

      3D Evaluation of the Lamina Cribrosa with Swept-Source Optical Coherence Tomography in Normal Tension Glaucoma
      Purpose Although the lamina cribrosa (LC) is the primary site of axonal damage in glaucoma, adequate methods to image and measure it are currently lacking. Here, we describe a noninvasive, in vivo method of evaluating the LC, based on swept-source optical coherence tomography (SS-OCT), and determine this methods ability to quantify LC thickness. Methods This study comprised 54 eyes, including normal (n = 18), preperimetric glaucoma (PPG; n = 18), and normal ...
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    7. Analysis of Retinal Nonperfusion Using Depth-Integrated Optical Coherence Tomography Images in Eyes with Branch Retinal Vein Occlusion

      Analysis of Retinal Nonperfusion Using Depth-Integrated Optical Coherence Tomography Images in Eyes with Branch Retinal Vein Occlusion
      PURPOSE: To assess the morphology of areas of complete retinal nonperfusion in eyes with branch retinal vein occlusion (BRVO) by enface images of optical coherence tomography (OCT). METHODS: Forty-six eyes with BRVO which underwent swept-source OCT (SS-OCT) and fluorescein angiography were enrolled. Depth-integrated images of the neural retina delineated by automated segmentation algorithm were obtained using SS-OCT. The findings in a 6 x 6-mm area on enface SS-OCT scans at ...
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    8. Speckle reduction in optical coherence tomography by matrix completion using bilateral random projection

      Speckle reduction in optical coherence tomography by matrix completion using bilateral random projection
      Speckle noise is problematic in optical coherence tomography (OCT) and often obscures the structure details. In this paper, we propose a new method to reduce speckle noise from multiply scanned OCT slices. The proposed method registers the OCT scans using a global alignment followed by a local alignment based on global and local motion estimation. Then low rank matrix completion using bilateral random projection is utilized to estimate the noise ...
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    9. Ophthalmological Imaging Apparatus And Ophthalmological Image Display Device

      Ophthalmological Imaging Apparatus And Ophthalmological Image Display Device
      Provided is a novel technique for ophthalmological image diagnosis. The ophthalmological imaging apparatus according to an embodiment comprises: an acquisition unit for acquiring three dimensional image data for an eye being tested using optical coherence tomography; a designating section for designating partial image data, which is a portion of the three dimensional image data that corresponds to a specified region of the eye being tested; a modifying section for generating ...
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    10. Speckle Reduction in Optical Coherence Tomography by Image Registration and Matrix Completion

      Speckle Reduction in Optical Coherence Tomography by Image Registration and Matrix Completion
      Speckle noise is problematic in optical coherence tomography (OCT). With the fast scan rate, swept source OCT scans the same position in the retina for multiple times rapidly and computes an average image from the multiple scans for speckle reduction. However, the eye movement poses some challenges. In this paper, we propose a new method for speckle reduction from multiply-scanned OCT slices. The proposed method applies a preliminary speckle reduction ...
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    11. En-face high-penetration optical coherence tomography imaging in polypoidal choroidal vasculopathy

      En-face high-penetration optical coherence tomography imaging in polypoidal choroidal vasculopathy
      Aim To observe the choroidal microstructure in polypoidal choroidal vasculopathy (PCV) using high-penetration optical coherence tomography (HP-OCT) with a long-wavelength light source that visualises tissue beneath the retinal pigment epithelium (RPE) and deep choroid, and to compare the findings with those of indocyanine green angiography (ICGA). Methods In this retrospective, non-invasive, observational case series, 19 eyes (18 patients) with PCV were observed using HP-OCT (swept source, 100 000 A-scans/s ...
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    12. Evaluation of congenital optic disc pits and optic disc colobomas by swept-source optical coherence tomography

      Evaluation of congenital optic disc pits and optic disc colobomas by swept-source optical coherence tomography
      Purpose:To investigate the structural abnormalities of optic disc pits and colobomas by swept-source optical coherence tomography (OCT). Methods: Sixteen eyes with congenital optic disc pits, and 7 eyes with optic disc colobomas were studied. Papillary and peripapillary areas were examined with swept-source OCT. The entire course of the pit or cavity and the spatial relationship between pits and retrobulbar subarachnoid space (SAS) were examined. Results: OCT images showed the ...
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    13. Comparison of spectral-domain and high-penetration OCT for observing morphologic changes in age-related macular degeneration and polypoidal choroidal vasculopathy

      Comparison of spectral-domain and high-penetration OCT for observing morphologic changes in age-related macular degeneration and polypoidal choroidal vasculopathy
      Background We compared the visibility of retinal and choroidal pathologies using high-penetration optical coherence tomography (HP-OCT) with a long-wavelength light source (1,050 nm) and conventional spectral-domain OCT (SD-OCT) in age-related macular degeneration (AMD). Methods One hundred and forty-six eyes were included: 63 eyes with AMD, 79 eyes with polypoidal choroidal vasculopathy (PCV), and four eyes with retinal angiomatous proliferation. The SD-OCT and HP-OCT images were compared using the grading ...
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    14. Age- and Hypertension-Dependent Changes in Retinal Vessel Diameter and Wall Thickness: An Optical Coherence Tomography Study

      Age- and Hypertension-Dependent Changes in Retinal Vessel Diameter and Wall Thickness: An Optical Coherence Tomography Study
      ...partment of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Kyoto, Japan , * Masahiro Akiba Affiliations + Topcon Corporation, Tokyo, Japan , * Ken Ogino Affiliations + Department of Opht...
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    15. Peripapillary Scleral Deformation and Retinal Nerve Fiber Damage in High Myopia Assessed With Swept-Source Optical Coherence Tomography

      Peripapillary Scleral Deformation and Retinal Nerve Fiber Damage in High Myopia Assessed With Swept-Source Optical Coherence Tomography
      Purpose To study peripapillary morphologic changes in highly myopic eyes using swept-source optical coherence tomography at a longer wavelength. Design Prospective cross-sectional study. Methods Peripapillary regions of 196 eyes of 107 patients with high myopia (refractive error, 8.0 diopters or axial length, 26.0 mm) were analyzed quantitatively and qualitatively with an swept-source optical coherence tomography prototype system that uses a tunable laser light source operated at a 100 ...
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    16. Macular choroidal thickness in normal pediatric population measured by Swept-Source Optical Coherence Tomography

      Macular choroidal thickness in normal pediatric population measured by Swept-Source Optical Coherence Tomography
      Purpose: To evaluate choroidal thickness in healthy pediatric population by swept-source longer-wavelength optical coherence tomography (SS-OCT). Methods: Cross-sectional comparative, non-interventional study. The macular area of 83 eyes from 43 pediatric patients (18 years) was studied with an SS-OCT prototype system. Macular choroidal thickness was manually determined at 750 m intervals by measuring the perpendicular distance from the posterior edge of retinal pigment epithelium (RPE) to the choroid/sclera junction, along ...
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  2. About Masahiro Akiba

    Masahiro Akiba is a Researcher at the Yamagata Promotional Organization for Industrial Technology, 2-2-1, Matsuei, Yamagata 990-2473, Japan.