1. Articles in category: Ophthalmology

    553-576 of 9439 « 1 2 ... 21 22 23 24 25 26 27 ... 392 393 394 »
    1. Investigation into surface interaction between the contact lens, the upper eyelid and cornea using optical coherence tomography

      Investigation into surface interaction between the contact lens, the upper eyelid and cornea using optical coherence tomography

      Background and Aim: Over 50% of the total 125 million contact lens users complain of discomforts due to contact lenses. The aim of the project is to understand the effect of contact lenses on the morphological parameters of cornea and eyelid surfaces. Methods and results: Five volunteers were recruited for this study (3 soft contact lens users and 2 non-users). The volunteers were imaged using a slit lamp and Optical Coherence Tomography (OCT) before and after a period of 6-7 hours. There was a significant increase in epidermal thickness of the eyelid for contact lens users compared to non-users. In ...

      Read Full Article
    2. Graph search: active appearance model based automated segmentation of retinal layers for optic nerve head centered OCT images

      Graph search: active appearance model based automated segmentation of retinal layers for optic nerve head centered OCT images

      In this paper, a novel approach combining the active appearance model (AAM) and graph search is proposed to segment retinal layers for optic nerve head(ONH) centered optical coherence tomography(OCT) images. The method includes two parts: preprocessing and layer segmentation. During the preprocessing phase, images is first filtered for denoising, then the B-scans are flattened. During layer segmentation, the AAM is first used to obtain the coarse segmentation results. Then a multi-resolution GS–AAM algorithm is applied to further refine the results, in which AAM is efficiently integrated into the graph search segmentation process. The proposed method was tested ...

      Read Full Article
    3. Mapping in-vivo optic nerve head strains caused by intraocular and intracranial pressures

      Mapping in-vivo optic nerve head strains caused by intraocular and intracranial pressures

      Although it is well documented that abnormal levels of either intraocular (IOP) or intracranial pressure (ICP) can lead to potentially blinding conditions, such as glaucoma and papilledema, little is known about how the pressures actually affect the eye. Even less is known about potential interplay between their effects, namely how the level of one pressure might alter the effects of the other. Our goal was to measure in-vivo the pressure-induced stretch and compression of the lamina cribrosa due to acute changes of IOP and ICP. The lamina cribrosa is a structure within the optic nerve head, in the back of ...

      Read Full Article
    4. Radial Peripapillary Capillary Density Measurement Using Optical Coherence Tomography Angiography in Early Glaucoma

      Radial Peripapillary Capillary Density Measurement Using Optical Coherence Tomography Angiography in Early Glaucoma

      Purpose: The purpose of the study was to compare radial peripapillary capillary (RPC) density between normal subjects and patients with early primary open-angle glaucoma (POAG) using optical coherence tomography angiography (OCT-A). Materials and Methods: A total of 24 patients with early POAG and age-matched 52 normal subjects underwent scanning with OCT-A imaging (RTVue XR-100, Avanti OCT). The enface angioflow images obtained were analyzed qualitatively for the RPC network, and RPC capillary density (CD) was measured in 8 sectors within a 3.45-mm-diameter circle around the optic disc, using the Bar-Selective Combination of Shifted Filter Responses (B-COSFIRE) method. CD and retinal ...

      Read Full Article
    5. Three-dimensional eye motion correction by Lissajous scan optical coherence tomography

      Three-dimensional eye motion correction by Lissajous scan optical coherence tomography

      A three-dimensional optical coherence tomography imaging method based on Lissajous scanning is presented. This method was designed to correct eye motion in OCT images. A Lissajous scanning pattern, which has a trajectory that frequently overlaps with itself, is adopted as the OCT scanning protocol to obtain measurement data. Eye motion artifacts are then corrected automatically by software. By comparing the images without and with motion correction, we show the effectiveness of our method. We performed an experiment and compared the results obtained by our method with the ground truths to verify its validity. The experimental results showed that our method ...

      Read Full Article
    6. AGE-RELATED CHANGES IN CHOROIDAL VASCULAR DENSITY OF HEALTHY SUBJECTS BASED ON IMAGE BINARIZATION OF SWEPT-SOURCE OPTICAL COHERENCE TOMOGRAPHY

      AGE-RELATED CHANGES IN CHOROIDAL VASCULAR DENSITY OF HEALTHY SUBJECTS BASED ON IMAGE BINARIZATION OF SWEPT-SOURCE OPTICAL COHERENCE TOMOGRAPHY

      Purpose: To analyze the vascular density of the choroid in a healthy population using swept-source optical coherence tomography. Methods: A cross-sectional, noninterventional study. Inclusion criteria: best-corrected visual acuity between 20/20 and 20/25, spherical equivalent between +/-3 diopters, no systemic or ocular diseases, and ages ranging between 3 and 85 years. One hundred and thirty-six eyes from 136 subjects were analyzed, 86 eyes (63.2%) were from male and 50 eyes (36.8%) from female subjects. The eyes were divided into different age groups to analyze the possible age-related changes. Twelve-millimeter horizontal, fovea-centered B-scans were used. Choroidal stroma and ...

      Read Full Article
    7. Enhanced Diagnostic Capability for Glaucoma of 3-Dimensional Versus 2-Dimensional Neuroretinal Rim Parameters Using Spectral Domain Optical Coherence Tomography

      Enhanced Diagnostic Capability for Glaucoma of 3-Dimensional Versus 2-Dimensional Neuroretinal Rim Parameters Using Spectral Domain Optical Coherence Tomography

      Purpose: To compare the diagnostic capability of 3-dimensional (3D) neuroretinal rim parameters with existing 2-dimensional (2D) neuroretinal and retinal nerve fiber layer (RNFL) thickness rim parameters using spectral domain optical coherence tomography (SD-OCT) volume scans. Materials and Methods: Design: Institutional prospective pilot study. Study population: 65 subjects (35 open-angle glaucoma patients, 30 normal patients). Observation procedures: One eye of each subject was included. SD-OCT was used to obtain 2D RNFL thickness values and 5 neuroretinal rim parameters [ie, 3D minimum distance band (MDB) thickness, 3D Bruch's membrane opening-minimum rim width (BMO-MRW), 3D rim volume, 2D rim area, and 2D ...

      Read Full Article
    8. UC Irvine Receives NIH Grant for Development of Real-Time Optical Coherence Elastography System to Quantify The Mechanical Properties of Retinal Layers In-Vivo

      UC Irvine Receives NIH Grant  for Development of Real-Time Optical Coherence Elastography System to Quantify The Mechanical Properties of Retinal Layers In-Vivo

      University of California at Irvine Receives a 2017 NIH Grant for $43,576 for Development of Real-Time Optical Coherence Elastography System to Quantify The Mechanical Properties of Retinal Layers In-Vivo. The principal investigator is Yueqiao Qu. The program began in 2017 and ends in 2019. Below is a summary of the proposed work. Age-related macular degeneration (AMD) is one of the leading causes of blindness among elderly people in the United States. Standard methods of diagnosis and progression tracking are fundus camera imaging and optical coherence tomography (OCT). Using these modalities, the anatomical changes of the retina during the onset ...

      Read Full Article
    9. Quantifying the effects of UV-A/riboflavin crosslinking on the elastic anisotropy and hysteresis of the porcine cornea by noncontact optical coherence elastography

      Quantifying the effects of UV-A/riboflavin crosslinking on the elastic anisotropy and hysteresis of the porcine cornea by noncontact optical coherence elastography

      The collagen fibril orientation of the cornea can provide critical information about cornea tissue health because diseases such as keratoconus and therapeutic interventions such as UV-A/riboflavin corneal collagen crosslinking (CXL) can alter the ultrastructural arrangement of collagen fibrils. Here, we quantify the elastic anisotropy and hysteresis of in situ porcine corneas as a function of intraocular pressure (IOP) with noncontact optical coherence elastography. Moreover, the effects of UV-A riboflavin corneal collagen crosslinking on the elastic anisotropy and hysteresis were evaluated. The propagation of an air-pulse induced elastic wave was imaged at stepped meridional angles by a home built phasestabilized ...

      Read Full Article
    10. Multiparameter thermo-mechanical OCT-based characterization of laser-induced cornea reshaping

      Multiparameter thermo-mechanical OCT-based characterization of laser-induced cornea reshaping

      Phase-sensitive optical coherence tomography (OCT) is used for visualizing dynamic and cumulative strains and corneashape changes during laser-produced tissue heating. Such non-destructive (non-ablative) cornea reshaping can be used as a basis of emerging technologies of laser vision correction. In experiments with cartilaginous samples, polyacrilamide phantoms and excised rabbit eyes we demonstrate ability of the developed OCT system to simultaneously characterize transient and cumulated strain distributions, surface displacements, scattering tissue properties and possibility of temperature estimation via thermal-expansion measurements. The proposed approach can be implemented in perspective real-time OCT systems for ensuring safety of new methods of laser reshaping of cornea.

      Read Full Article
    11. Applanation optical coherence elastography: noncontact measurement of intraocular pressure, corneal biomechanical properties, and corneal geometry with a single instrument

      Applanation optical coherence elastography: noncontact measurement of intraocular pressure, corneal biomechanical properties, and corneal geometry with a single instrument

      Current clinical tools provide critical information about ocular health such as intraocular pressure (IOP). However, they lack the ability to quantify tissue material properties, which are potent markers for ocular tissue health and integrity. We describe a single instrument to measure the eye-globe IOP, quantify corneal biomechanical properties, and measure corneal geometry with a technique termed applanation optical coherence elastography (Appl-OCE). An ultrafast OCT system enabled visualization of corneal dynamics during noncontact applanation tonometry and direct measurement of micro air-pulse induced elastic wave propagation. Our preliminary results show that the proposed Appl-OCE system can be used to quantify IOP, corneal ...

      Read Full Article
    12. Deep Learning Is Effective for Classifying Normal versus Age-Related Macular Degeneration Optical Coherence Tomography Images

      Deep Learning Is Effective for Classifying Normal versus Age-Related Macular Degeneration Optical Coherence Tomography Images

      Purpose The advent of electronic medical records (EMRs) with large electronic imaging databases along with advances in deep neural networks with machine learning has provided a unique opportunity to achieve milestones in automated image analysis. Optical coherence tomography (OCT) is the most common imaging modality in ophthalmology and represents a dense and rich data set when combined with labels derived from the EMR. We sought to determine whether deep learning could be utilized to distinguish normal OCT images from images from patients with age-related macular degeneration (AMD). Design EMR and OCT database study. Subjects Normal and AMD patients who underwent ...

      Read Full Article
    13. Wide-Field En Face Swept-Source Optical Coherence Tomography Features of Extrafoveal Retinoschisis in Highly Myopic Eyes

      Wide-Field En Face Swept-Source Optical Coherence Tomography Features of Extrafoveal Retinoschisis in Highly Myopic Eyes

      Purpose : To evaluate the features of extrafoveal retinoschisis (EFRS) in highly myopic eyes detected by swept-source optical coherence tomography (SS-OCT). Methods : In this retrospective case series, 89 eyes of 65 patients with high myopia and coexisting EFRS were included. The participants underwent a comprehensive ophthalmologic examination, including visual acuity, ocular biometry, refraction, and perimetry. Three-dimensional wide-field scans were obtained with SS-OCT, and en face images were reconstructed with custom software. En face OCT features of EFRS were determined by two ophthalmologists masked to clinical characteristics. The associations of EFRS subtypes with ocular biometry and other OCT changes were evaluated as ...

      Read Full Article
    14. VISUALIZATION OF THE MACULA IN GAS-FILLED EYES: Spectral Domain Optical Coherence Tomography Versus Swept-Source Optical Coherence Tomography

      VISUALIZATION OF THE MACULA IN GAS-FILLED EYES: Spectral Domain Optical Coherence Tomography Versus Swept-Source Optical Coherence Tomography

      Purpose: To compare the visualization of the macula between spectral domain optical coherence tomography (SD-OCT) and swept-source OCT (SS-OCT) in gas-filled eyes. Methods: Sixty-one patients with common indications of gas tamponade, including 27 with macular holes and 34 with rhegmatogenous retinal detachment, who were treated with vitrectomy and gas tamponade were imaged using both SD-OCT (3D-OCT 2000, Topcon, Tokyo, Japan) and SS-OCT (DRI-OCT, Topcon) at 1, 3, and 7 days after the surgery. Good visualization of the macular area was defined as 1) visible foveal contour and discriminable status of hole (open or closed) for macular hole and 2) visible ...

      Read Full Article
    15. Optical coherence tomography angiography of iris microhemangiomatosis

      Optical coherence tomography angiography of iris microhemangiomatosis

      Purpose To report optical coherence tomography angiography (OCTA) of iris microhemangiomatosis. Observations A 75-year-old asymptomatic Caucasian man was found to have bilateral pupillary vascular lesions during cataract evaluation. Visual acuity was counting fingers in the right eye (OD) and 20/40 in the left eye (OS) with normal intraocular pressures in both eyes (OU). In each eye there were multifocal, round, dark red, pinpoint vascular tufts at the pupillary margin, randomly distributed and numbering 1 in OD and 7 in OS, each measuring 0.2–0.3 mm in diameter and without active bleeding or hyphema. Fundus examination OU was ...

      Read Full Article
    16. CHOROIDAL THICKNESS IN DIABETIC RETINOPATHY ASSESSED WITH SWEPT-SOURCE OPTICAL COHERENCE TOMOGRAPHY

      CHOROIDAL THICKNESS IN DIABETIC RETINOPATHY ASSESSED WITH SWEPT-SOURCE OPTICAL COHERENCE TOMOGRAPHY

      Purpose: To compare the choroidal thickness (CT) of diabetic eyes (different stages of disease) with controls, using swept-source optical coherence tomography. Methods: A multicenter, prospective, cross-sectional study of diabetic and nondiabetic subjects using swept-source optical coherence tomography imaging. Choroidal thickness maps, according to the nine Early Treatment Diabetic Retinopathy Study (ETDRS) subfields, were obtained using automated software. Mean CT was calculated as the mean value within the ETDRS grid, and central CT as the mean in the central 1 mm. Diabetic eyes were divided into four groups: no diabetic retinopathy (No DR), nonproliferative DR (NPDR), NPDR with diabetic macular edema ...

      Read Full Article
    17. QUANTIFICATION OF INTRARETINAL HARD EXUDATES IN EYES WITH DIABETIC RETINOPATHY BY OPTICAL COHERENCE TOMOGRAPHY

      QUANTIFICATION OF INTRARETINAL HARD EXUDATES IN EYES WITH DIABETIC RETINOPATHY BY OPTICAL COHERENCE TOMOGRAPHY

      Purpose: To evaluate the reproducibility of intraretinal hard exudate (HE) quantification from spectral domain optical coherence tomography (SD-OCT) images of eyes with diabetic retinopathy (DR). Methods: Cases with diabetic macular edema were enrolled. The area of HE obtained by B-scan segmentation was compared with the area obtained by en face segmentation. Results: The mean +/- SD for the HE area was 1.78 +/- 1.37 mm2 with B-scan segmentation and 0.72 +/- 0.82 mm2 with the automated en face analysis tool; the absolute difference was 1.01 +/- 0.64 mm2. There was excellent correlation in total HE area between the ...

      Read Full Article
    18. Vitreomacular Hyaloid Attachment: A Normal Optical Coherence Tomography Finding

      Vitreomacular Hyaloid Attachment: A Normal Optical Coherence Tomography Finding

      Dear Editor, We would like to comment on the excellent article by Sahni, Stanga, Wong, and Harding [1]. In their paper, a number of descriptive terms for optical coherence tomography (OCT) analysis are defined in age-related macular degeneration (AMD) patients with subfoveal choroidal neovascularization undergoing treatment with photodynamic therapy. One term, “vitreomacular hyaloid attachment (VMHA),” was used to refer to incomplete separation of the posterior hyaloid with attachment at the macula. Twenty of 56 patients (35.7%) included in the study had VMHA on OCT. We would like to point out that this vitreomacular configuration is identical to that described ...

      Read Full Article
    19. Effect of Surgical Intraocular Pressure Lowering on Peripapillary and Macular Vessel Density in Glaucoma Patients: An Optical Coherence Tomography Angiography Study

      Effect of Surgical Intraocular Pressure Lowering on Peripapillary and Macular Vessel Density in Glaucoma Patients: An Optical Coherence Tomography Angiography Study

      Purpose: To measure the influence of surgically induced intraocular pressure lowering on peripapillary and macular vessel density in glaucoma patients using optical coherence tomography angiography. Methods: Twenty-one eyes of 21 patients with open-angle glaucoma scheduled for filtering surgery were enrolled prospectively. Using optical coherence tomography angiography, vessel density was quantified within the peripapillary and macular regions, before and 1 month after filtering surgery. Change in vessel density was calculated for all analyzed areas. Results: One month after surgery, the mean intraocular pressure reduction was 44.2%+/-4.8% (range, 15.2% to 77.1%). The mean change in vessel density ...

      Read Full Article
    20. Optical coherence tomography angiography in chorioretinal disorders

      Optical coherence tomography angiography in chorioretinal disorders

      Optical coherence tomography angiography (OCTA) is a novel imaging modality that incorporates blood motion contrast to create angiograms of the retinal vasculature in a noninvasive manner, without the use of dye. It is a safe procedure and can be repeated as frequently as desired. The use of OCTA for delineation of choroidal neovascular membranes, for the study of microvascular abnormalities in diabetic patients, to assess nonperfused areas in retinal occlusions and vascular changes in macular telangiectasia are some of the potential OCTA applications. However, it is not free of drawbacks. Major limitations include the small field of view and its ...

      Read Full Article
    21. How Will Optometry Respond to Technological Evolution?

      How Will Optometry Respond to Technological Evolution?

      I recently visited the Computer History Museum in Mountain View, California, in the heart of Silicon Valley. This museum chronicles the evolution of computing technology from slide rules to self-driving cars. Their exhibits showcase fascinating stories of what the power of the human mind can achieve. The tangible manifestations of these achievements on display played important parts in ending wars (the ENIGMA cipher machine or the Manhattan Project), walking on the moon, computer animation, the world-wide web, and today’s smartphones. These achievements required advances in engineering, math, sciences, art, language, and culture. However, the real stories behind the innovations ...

      Read Full Article
      Mentions: Michael D. Twa
    22. SD-OCT and Adaptive Optics Imaging of Outer Retinal Tubulation

      SD-OCT and Adaptive Optics Imaging of Outer Retinal Tubulation

      Typically, it is thought that the atrophy of the retinal pigmented epithelium and choroid leads to a complete loss of the overlying photoreceptors. 1 Thus, in atrophic outer retinal disorders, such as geographic atrophy, the photoreceptors are often assumed to be absent. This assumption has come into question with the recognition of outer retinal tubulation by Zweifel et al. 2 Outer retinal tubulations are tubular structures that are visualized on spectral domain optical coherence tomography (SD-OCT) in single B-scans as nonedematous circular or ovoid structures at the level of the outer nuclear layer found near or overlying outer retinal atrophy ...

      Read Full Article
    23. Four-dimensional microscope- integrated optical coherence tomography to enhance visualization in glaucoma surgeries

      Four-dimensional microscope- integrated optical coherence tomography to enhance visualization in glaucoma surgeries

      We report the first use of swept-source microscope-integrated optical coherence tomography (SS-MIOCT) capable of live four-dimensional (4D) (three-dimensional across time) imaging intraoperatively to directly visualize tube shunt placement and trabeculectomy surgeries in two patients with severe open-angle glaucoma and elevated intraocular pressure (IOP) that was not adequately managed by medical intervention or prior surgery. We performed tube shunt placement and trabeculectomy surgery and used SS-MIOCT to visualize and record surgical steps that benefitted from the enhanced visualization. In the case of tube shunt placement, SS-MIOCT successfully visualized the scleral tunneling, tube shunt positioning in the anterior chamber, and tube shunt ...

      Read Full Article
    24. Intraoperative optical coherence tomography in anterior segment surgeries

      Intraoperative optical coherence tomography in anterior segment surgeries

      Intraoperative optical coherence tomography (iOCT) is a noninvasive imaging modality that provides a real-time dynamic feedback of the various surgical steps. Comprehensive literature search was performed in MEDLINE using “intraoperative optical coherence tomography” and “iOCT” as keywords. The use of iOCT as an aid to decision-making has been successfully reported in cases undergoing keratoplasty, implantable Collamer lens (ICL) implantation as well as cataract surgery. iOCT helps to assess the graft-host relationship in penetrating keratoplasty. It helps confirm the presence of a big bubble, detect subclinical big bubbles and guide layer by layer stromal dissection in cases of deep anterior lamellar ...

      Read Full Article
    553-576 of 9439 « 1 2 ... 21 22 23 24 25 26 27 ... 392 393 394 »
  1. Categories

    1. Applications:

      Art, Cardiology, Dentistry, Dermatology, Developmental Biology, Gastroenterology, Gynecology, Microscopy, NDE/NDT, Neurology, Oncology, Ophthalmology, Other Non-Medical, Otolaryngology, Pulmonology, Urology
    2. Business News:

      Acquisition, Clinical Trials, Funding, Other Business News, Partnership, Patents
    3. Technology:

      Broadband Sources, Probes, Tunable Sources
    4. Miscellaneous:

      Jobs & Studentships, Student Theses, Textbooks
  2. Popular Articles

  3. Organizations in the News

    1. (7 articles) National Institutes of Health
    2. (4 articles) Oregon Health & Science University
    3. (4 articles) Tufts University
    4. (4 articles) University of Washington
    5. (3 articles) Center for Ophthalmic Optics and Lasers
    6. (3 articles) UCSD
    7. (3 articles) FDA
    8. (3 articles) Cleveland Clinic
    9. (3 articles) Medical University of Vienna
    10. (3 articles) Singapore Eye Research Institute
    11. (2 articles) National University of Singapore
    12. (2 articles) Fudan University
  4. People in the News

    1. (4 articles) Justis P. Ehlers
    2. (4 articles) Robert N. Weinreb
    3. (3 articles) David Huang
    4. (3 articles) Nadia K. Waheed
    5. (2 articles) Sunil K. Srivastava
    6. (2 articles) Tien Yin Wong
    7. (2 articles) Jay S. Duker
    8. (2 articles) Yali Jia
    9. (2 articles) Ruikang K. Wang
    10. (2 articles) Giovanni Staurenghi
    11. (2 articles) Peter K. Kaiser
    12. (2 articles) Susanne Binder
  5. OCT Companies in the News

    1. (12 articles) Optovue
    2. (7 articles) Carl Zeiss Meditec
    3. (5 articles) Topcon Medical Systems
    4. (4 articles) Heidelberg Engineering
    5. (3 articles) Bioptigen
    6. (1 articles) Leica
    7. (1 articles) Basler
    8. (1 articles) Haag-Streit
    9. (1 articles) Notal Vision
    10. (1 articles) Optos