All Articles from Tetsuro Oshika -Optical Coherence Tomography News

Articles from Tetsuro Oshika

1-24 of 28 1 2 »
1. Visualization of Anterior Chamber Angle Structures With Scattering- and Polarization-Sensitive Anterior Segment Optical Coherence Tomography
  
  Explore TVST Journal Dec 30 2021 Ophthalmology
  
  Purpose: The purpose of this study was to compare three optical coherence tomography (OCT) modalities in the observation of anterior chamber angle structures; trabecular meshwork (TM), Schlemm's canal (SC), and band of extracanalicular limbal lamina (BELL). Methods: Three OCT modalities were used: (1) 2 × 2 Jones-matrix scattering OCT (S-OCT) representing conventional intensity OCT, (2) polarization-diverse S-OCT that was calculated as summation of all elements of the Jones-matrix to eliminate the influence of artifacts caused by sample birefringence, and (3) polarization-sensitive OCT (PS-OCT) to assess depth-resolved phase retardation. Results: In a total of 97 eyes of 55 subjects, nasal and ...
  Read Full Article
  
  Comment
  
  Mentions: University of Tsukuba
2. Label-free functional and structural imaging of liver microvascular complex in mice by Jones matrix optical coherence tomography
  
  Explore Nature Publishing Group Oct 9 2021 Urology
  
  We demonstrate label-free imaging of the functional and structural properties of microvascular complex in mice liver. The imaging was performed by a custom-built Jones-matrix based polarization sensitive optical coherence tomography (JM-OCT), which is capable of measuring tissue's attenuation coefficient, birefringence, and tiny tissue dynamics. Two longitudinal studies comprising a healthy liver and an early fibrotic liver model were performed. In the healthy liver, we observed distinctive high dynamics beneath the vessel at the initial time point (0 h) and reappearance of high dynamics at 32-h time point. In the early fibrotic liver model, we observed high dynamics signal that ...
  Read Full Article
  
  Comment
  
  Mentions: University of Tsukuba
3. Rotational stability of modified toric intraocular lens
  
  Explore Journals | PLOS Mar 1 2021
  
  We evaluated the rotational stability of a new toric intraocular lens (IOL), HOYA XY-1 toric IOL that is an improved version of HOYA 355 toric IOL, with longer overall length (13.0 mm vs. 12.5 mm), shortened unfolding time, and texture processing of the surface of haptics. Data from 193 eyes of 165 patients (76.4 ± 8.3 years old) with preoperative corneal astigmatism exceeding 0.75 diopters who had undergone phacoemulsification and toric IOL implantation were collected and analyzed. Corneal astigmatism, refractive astigmatism, and uncorrected (UDVA) and corrected distance visual acuity (CDVA) were evaluated before and 1 day ...
  Read Full Article
  
  Comment
  
  Mentions: Carl Zeiss Meditec Tomey Corporation Alcon
4. Optical coherence tomography-based tissue dynamics imaging for longitudinal and drug response evaluation of tumor spheroids
  
  Explore OSA | OSA Publishing Dec 9 2020
  
  We present optical coherence tomography (OCT)-based tissue dynamics imaging method to visualize and quantify tissue dynamics such as subcellular motion based on statistical analysis of rapid-time-sequence OCT signals at the same location. The analyses include logarithmic intensity variance (LIV) method and two types of OCT correlation decay speed analysis (OCDS). LIV is sensitive to the magnitude of the signal fluctuations, while OCDSs including early- and late-OCDS (OCDS e and OCDS l , respectively) are sensitive to the fast and slow tissue dynamics, respectively. These methods were able to visualize and quantify the longitudinal necrotic process of a human breast adenocarcinoma ...
  Read Full Article
  
  Comment
  
  Mentions: University of Tsukuba
5. Influence of pterygium size on corneal higher-order aberration evaluated using anterior-segment optical coherence tomography
  
  Explore BMC Ophthalmology Jul 14 2018 Ophthalmology
  
  Background The prospective observation study aimed to evaluate changes in corneal higher-order aberrations induced by advancement of pterygium using an anterior-segment optical coherence tomography (AS-OCT) and Zernike aberration analysis. Methods The corneal topography of 284 eyes with primary pterygia originating from the nasal region was measured using an AS-OCT (SS-1000, Tomey). With anterior corneal elevation data, Zernike polynomial coefficients were calculated in diameters of 1.0, 3.0, and 5.0 mm, and the coma, spherical, coma-like, spherical-like, and total higher-order aberrations were obtained. Pterygium size was also measured as a ratio of positions of the pterygium end with respect ...
  Read Full Article
  
  Comment
  
  Mentions: Tomey Corporation
6. Comparison of intensity, phase retardation, and local birefringence images for filtering blebs using polarization-sensitive optical coherence tomography
  
  Explore Nature Publishing Group May 19 2018
  
  Polarization-sensitive optical coherence tomography (PS-OCT) allows the recording of depth-resolved polarimetric measurements. It has been reported that phase retardation and local birefringence images can noninvasively detect fibrotic area in blebs after glaucoma surgery. Evaluation of scar fibrosis in blebs is important not only for predicting bleb function, but also for planning revision trabeculectomy. Herein, we characterize the intensity, phase retardation, and local birefringence images of blebs using PS-OCT. A total of 85 blebs from 85 patients who had undergone trabeculectomy were examined. Both phase retardation and local birefringence images detected fibrotic changes in blebs after glaucoma surgery. Phase retardation images ...
  Read Full Article
  
  Comment
  
  Mentions: University of Tsukuba
7. Changes In Metamorphopsia And Optical Coherence Tomography Findings After Successful Retinal Detachment Surgery
  
  Explore LWW Online Mar 22 2018 Ophthalmology
  
  Purpose: To investigate changes in metamorphopsia after rhegmatogenous retinal detachment surgery and to evaluate the relationship between metamorphopsia and retinal microstructures assessed with optical coherence tomography . Methods: The study included 47 eyes of 47 patients undergoing retinal detachment surgery. We examined the severity of metamorphopsia using M-CHARTS, best-corrected visual acuity, and optical coherence tomography images. All data were recorded before and 3, 6, and 12 months after surgery, except for M-CHARTS which were recorded only postoperatively. Results: Metamorphopsia scores at 3, 6, and 12 months postoperatively were 0.46 ± 0.51, 0.41 ± 0.44, and 0.28 ± 0.37 ...
  Read Full Article
  
  Comment
8. Quantitative Evaluation of Phase Retardation in Filtering Blebs Using Polarization-Sensitive Optical Coherence Tomography
  
  Explore IOVS Journal Nov 6 2016 Ophthalmology
  
  Purpose : Polarization-sensitive optical coherence tomography (PS-OCT) can detect and evaluate scar fibrosis of the filtering blebs after glaucoma surgery. Although the change in phase retardation reportedly reflects bleb function, quantitative assessment of phase retardation in ocular tissues has not been conducted. We aimed to establish quantitative methods to investigate changes in phase retardation in the blebs after surgery using PS-OCT. Methods : Twenty-two blebs of 22 patients who had undergone glaucoma filtration surgery were consecutively examined for 4 months. Phase retardation was measured by PS-OCT and quantitatively analyzed to evaluate its relationship with bleb function based on intraocular pressure and medication ...
  Read Full Article
  
  Comment
  
  Mentions: University of Tsukuba
9. Objective Evaluation of Functionality of Filtering Bleb Based on Polarization-Sensitive Optical Coherence Tomography
  
  Explore IOVS Journal May 3 2016 Ophthalmology
  
  Purpose : The fibrosis score is a new diagnostic score that we have developed to evaluate the function of bleb structures after glaucoma filtration surgery using polarization-sensitive optical coherence tomography (PS-OCT). This study aims to assess the efficacy of the fibrosis score in discriminating nonfunctional from the functional blebs. Methods : A total of 20 patients who had undergone glaucoma filtration surgery were imaged at different time periods after surgery using PS-OCT. Birefringence tomography of blebs was obtained from PS-OCT, and the fibrosis score was computed for each patient. The fibrosis score is defined as the area of occupation of high birefringence ...
  Read Full Article
  
  Comment
  
  Mentions: University of Tsukuba
10. Repeatability of Corneal Phase Retardation Measurements by Polarization-Sensitive Optical Coherence Tomography
  
  Explore IOVS Journal May 28 2015 Ophthalmology
  
  Purpose. Polarization-sensitive optical coherence tomography (PS-OCT) can evaluate internal tissue structures of the cornea, such as collagen fibers, by phase retardation measurement. In this study, we assessed the repeatability of corneal phase retardation measurements using anterior segment PS-OCT. Methods. A total of 173 eyes of 173 patients were measured using PS-OCT. In total, 58 eyes of young subjects with normal corneas, 28 eyes of old subjects with normal corneas, 26 eyes with corneal dystrophy or degeneration, 37 eyes with corneal transplantation, and 24 eyes with keratoconus were evaluated. The 3-mm diameter average of en face phase retardation of the posterior ...
  Read Full Article
  
  Comment
  
  Mentions: University of Tsukuba
11. Noninvasive Evaluation of Phase Retardation in Blebs after Glaucoma Surgery Using Anterior Segment Polarization-Sensitive Optical Coherence Tomography
  
  Explore iovs.org Jul 31 2014 Ophthalmology
  
  Purpose: Evaluation of bleb morphology using anterior segment optical coherence tomography (OCT) can offer important information regarding bleb function after glaucoma surgery. However, analysis of tissue properties, such as scar fibrosis of blebs, is difficult with conventional OCT. The birefringence of the blebs as susceptible measure of fibrosis scar was evaluated using polarization-sensitive OCT (PS-OCT) and its relation with bleb function was assessed. Methods: One hundred and fifty-three blebs of 122 patients that had undergone trabeculectomy or an Ex-Press tube shunt were examined. Also, in 14 blebs of 12 patients, consecutive measurements were performed for 2 months after surgery. The ...
  Read Full Article
  
  Comment
  
  Mentions: University of Tsukuba
12. Bayesian maximum likelihood estimator of phase retardation for quantitative polarization-sensitive optical coherence tomography
  
  Explore opticsinfobase.org Jun 26 2014
  
  This paper presents the theory and numerical implementation of a maximum likelihood estimator for local phase retardation (i.e., birefringence) measured using Jones-matrix-based polarization sensitive optical coherence tomography. Previous studies have shown conventional mean estimations of phase retardation and birefringence are significantly biased in the presence of system noise. Our estimator design is based on a Bayes’ rule that relates the distributions of the measured birefringence under a particular true birefringence and the true birefringence under a particular measured birefringence. We used a Monte-Carlo method to calculate the likelihood function that describes the relationship between the distributions and numerically implement ...
  Read Full Article
  
  Comment
  
  Mentions: Institute of Applied Physics University of Tsukuba
13. Scleral birefringence as measured by polarization-sensitive optical coherence tomography and ocular biometric parameters of human eyes in vivo
  
  Explore opticsinfobase.org Apr 3 2014 Ophthalmology
  
  The relationship between scleral birefringence and biometric parameters of human eyes in vivo is investigated. Scleral birefringence near the limbus of 21 healthy human eyes was measured using polarization-sensitive optical coherence tomography. Spherical equivalent refractive error, axial eye length, and intraocular pressure (IOP) were measured in all subjects. IOP and scleral birefringence of human eyes in vivo was found to have statistically significant correlations ( r = −0.63, P = 0.002). The slope of linear regression was −2.4 × 10 −2 deg/μm/mmHg. Neither spherical equivalent refractive error nor axial eye length had significant correlations with scleral birefringence. To evaluate ...
  Read Full Article
  
  Comment
  
  Mentions: Osaka University University of Tsukuba Tokyo Medical University
14. Metamorphopsia and Optical Coherence Tomography Findings After Rhegmatogenous Retinal Detachment Surgery
  
  Explore American Journal of Ophthalmology Oct 8 2013 Ophthalmology
  
  Purpose To investigate the relationship between metamorphopsia and macular morphologic changes after successful repair of rhegmatogenous retinal detachment (RD). Design Prospective, interventional, consecutive study. Methods The study included 129 eyes of 129 patients who had undergone successful retinal reattachment surgery. The severity of metamorphopsia was recorded using M-CHARTS and foveal microstructure was assessed with spectral-domain optical coherence tomography (OCT) at 6-12 months postoperatively. Results The mean metamorphopsia score was 0.30 ± 0.46, and 50 of 129 patients (39%) had metamorphopsia. Metamorphopsia was more severe in eyes with macula-off rhegmatogenous RD than those with macula-on ( P < .001). Eighteen of 50 ...
  Read Full Article
  
  Comment
  
  Mentions: University of Tsukuba
15. Comparison of three-dimensional optical coherence tomography and combining a rotating Scheimpflug camera with a Placido topography system for forme fruste keratoconus diagnosis
  
  Explore BJO Online Oct 2 2013 Ophthalmology
  
  Objective To evaluate the ability of parameters measured by three-dimensional (3D) corneal and anterior segment optical coherence tomography (CAS-OCT) and a rotating Scheimpflug camera combined with a Placido topography system (Scheimpflug camera with topography) to discriminate between normal eyes and forme fruste keratoconus. Methods Forty-eight eyes of 48 patients with keratoconus, 25 eyes of 25 patients with forme fruste keratoconus and 128 eyes of 128 normal subjects were evaluated. Anterior and posterior keratometric parameters (steep K, flat K, average K), elevation, topographic parameters, regular and irregular astigmatism (spherical, asymmetry, regular and higher-order astigmatism) and five pachymetric parameters (minimum, minimum–median ...
  Read Full Article
  
  Comment
  
  Mentions: University of Tsukuba Tomey Corporation
16. Comparison of three-dimensional optical coherence tomography and combining a rotating Scheimpflug camera with a Placido topography system for forme fruste keratoconus diagnosis
  
  Explore BJO Online Sep 30 2013 Ophthalmology
  
  Objective To evaluate the ability of parameters measured by three-dimensional (3D) corneal and anterior segment optical coherence tomography (CAS-OCT) and a rotating Scheimpflug camera combined with a Placido topography system (Scheimpflug camera with topography) to discriminate between normal eyes and forme fruste keratoconus. Methods Forty-eight eyes of 48 patients with keratoconus, 25 eyes of 25 patients with forme fruste keratoconus and 128 eyes of 128 normal subjects were evaluated. Anterior and posterior keratometric parameters (steep K, flat K, average K), elevation, topographic parameters, regular and irregular astigmatism (spherical, asymmetry, regular and higher-order astigmatism) and five pachymetric parameters (minimum, minimum–median ...
  Read Full Article
  
  Comment
  
  Mentions: University of Tsukuba
17. Keratoconus diagnosis using anterior segment polarization-sensitive optical coherence tomography
  
  Explore iovs.org Jan 25 2013 Ophthalmology
  
  Purpose: To investigate the tissue properties of keratoconic corneas and normal control in vivo by using polarization-sensitive optical coherence tomography (PS-OCT) and evaluate early keratoconus by the area under the receiver-operating curve and Mahalanobis distances analysis. Methods: Thirty one eyes of 20 patients with keratoconus, seven eyes of four patients with keratoconus suspect, and 25 eyes of 25 normal subjects were investigated by PS-OCT and corneal and anterior segment (CAS)-OCT. Average of en face phase retardation of the posterior surface of the cornea, curvature, videokeratographic parameters, regular and irregular astigmatism, pachymetry map, and elevation were measured. The AROC of ...
  Read Full Article
  
  Comment
  
  Mentions: University of Tsukuba
18. Optical Rheology of Porcine Sclera by Birefringence Imaging
  
  Explore PLoS ONE Sep 6 2012
  
  Purpose To investigate a relationship between birefringence and elasticity of porcine sclera ex vivo using polarization-sensitive optical coherence tomography (PS-OCT). Methods Elastic parameters and birefringence of 19 porcine eyes were measured. Four pieces of scleral strips which were parallel to the limbus, with a width of 4 mm, were dissected from the optic nerve head to the temporal side of each porcine eye. Birefringence of the sclera was measured with a prototype PS-OCT. The strain and force were measured with a uniaxial material tester as the sample was stretched with a speed of 1.8 mm/min after preconditioning. A ...
  Read Full Article
  
  Comment
  
  Mentions: University of Tsukuba Tokyo Medical University
19. Birefringence measurement of cornea and anterior segment by office-based polarization-sensitive optical coherence tomography
  
  Explore opticsinfobase.org Jul 27 2011 Ophthalmology
  
  We present a case series of cornea and anterior segment disorders investigated by an office-based polarization-sensitive optical coherence tomography (PS-OCT). Blebs of glaucoma patients treated by trabeculectomy, and corneas of keratoconus and keratoplasty patients were measured by PS-OCT. Birefringence formations in trabeculectomy bleb were measured in 1 control eye and 3 eyes of trabeculectomy model rabbits. Polarization insensitive scattering OCT and the depth-resolved birefringence were measured simultaneously by PS-OCT. Abnormal birefringence was observed in keratoconus cases with advanced thinning and with a rupture of Descemet’s membrane. The graft-host interface of the keratoplasty case showed abnormal birefringence. The appearance of ...
  Read Full Article
  
  Comment
  
  Mentions: University of Tsukuba
20. Repeatability and reproducibility of anterior chamber volume measurements using 3-dimensional corneal and anterior segment optical coherence tomography
  
  Explore Journal of Cataract & Refractive Surgery Feb 28 2011 Ophthalmology
  
  Purpose: To evaluate the repeatability and reproducibility of anterior chamber volume (ACV) measurements using swept-source 3-dimensional corneal and anterior segment optical coherence tomography (CAS-OCT) and dual Scheimpflug imaging.Setting: Department of Ophthalmology, Institute of Clinical Medicine, University of Tsukuba, Ibaraki, Japan.Design: Nonrandomized clinical trial.Methods: Measurements were taken in normal eyes (subject group) and in eyes with primary angle closure (PAC) (patient group). In the subject group, the entire ACV and the central 8.0 mm diameter ACV were measured using CAS-OCT and dual Scheimpflug imaging. In the patient group, the entire ACV and 8.0 mm ACV were ...
  Read Full Article
  
  Comment
  
  Mentions: University of Tsukuba
21. Wound Architecture of Clear Corneal Incision With or Without Stromal Hydration Observed With 3-Dimensional Optical Coherence Tomography
  
  Explore American Journal of Ophthalmology Jan 12 2011 Ophthalmology
  
  Purpose To evaluate wound architectures of a clear corneal incision and the duration of stromal edema caused by intentional hydration in cataract surgery using 3-dimensional (3-D) cornea and anterior segment optical coherence tomography (OCT). Design Prospective, randomized study. Methods On 30 eyes of 23 patients, cataract surgery was performed through a clear corneal incision created with a 2.4-mm blade. After confirming the water tightness of the clear corneal incision at the end of surgery, 15 randomly selected eyes received stromal hydration, and the remaining 15 eyes did not. Using the 3-D cornea and anterior segment optical coherence tomography, wound ...
  Read Full Article
  
  Comment
  
  Mentions: University of Tsukuba
22. Visibility of trabecular meshwork by standard and polarization-sensitive optical coherence tomography
  
  Explore SPIE Digital Library Dec 23 2010 Ophthalmology
  
  Polarization-sensitive optical coherence tomography (PS-OCT) is known to be advantageous because of its additional tissue-specific contrast of the anterior eye. So far, this advantage has been shown only qualitatively. We evaluate the improved visibility afforded by 3-D PS corneal and anterior eye segment OCT (PS-CAS-OCT) in visualizing the trabecular meshwork (TM) based on statistical evidences. A total of 31 normal subjects participated in this study. The anterior eye segments of both the eyes of the subjects are scanned using a custom-made PS-CAS-OCT and the standard-scattering OCT (S-OCT) and polarization-sensitive phase-retardation OCT (P-OCT) images are obtained. Three graders grade the visibility ...
  Read Full Article
  
  Comment
  
  Mentions: Carl Zeiss Meditec University of Tsukuba
23. Repeatability and reproducibility of anterior ocular biometric measurements with 2-dimensional and 3-dimensional optical coherence tomography
  
  Explore Journal of Cataract & Refractive Surgery Oct 28 2010 Ophthalmology
  
  Purpose To evaluate the repeatability and reproducibility of central corneal thickness (CCT), anterior chamber depth (ACD), and anterior chamber width (ACW) measurements using 3-dimensional (3-D) corneal and anterior segment optical coherence tomography (CAS-OCT) and 2-dimensional (2-D) anterior segment OCT (AS-OCT). Setting Department of Ophthalmology, Institute of Clinical Medicine, University of Tsukuba, Ibaraki, Japan. Design Nonrandomized clinical trial. Methods The CCT, ACD, and ACW were measured in normal eyes using a prototype 3-D swept-source CAS-OCT device and a 2-D time-domain AS-OCT device (Visante). The coefficient of repeatability and reproducibility and the intraclass correlation coefficient (ICC) were calculated to evaluate the repeatability ...
  Read Full Article
  
  Comment
  
  Mentions: Carl Zeiss Meditec University of Tsukuba
24. Investigation of multifocal choroiditis with panuveitis by three-dimensional high-penetration optical coherence tomography
  
  Explore www3.interscience.wiley.com Jul 2 2009 Ophthalmology
  
  A single case of multifocal choroiditis with panuveitis (MFCPU) was investigated by a three-dimensional (3-D) high-penetration optical coherence tomography. The HP-OCT is based on a swept-source OCT technology, uses a probe beam with a center wavelength of 1060 nm, and possesses a depth resolution of 10.4 [mu] min tissue. Two eyes of an MFCPU patient were involved in this study. The eyes were also examined by color fundus photograph, fluorescein angiography (FA), and indocyanine green angiography (ICGA). Findings in these four modalities are comparatively discussed. The OCT scans revealed the following characteristic properties of the lesion sites. Thinning of ...
  Read Full Article
  
  Comment
  
  Mentions: University of Tsukuba
1-24 of 28 1 2 »