1. Articles in category: Ophthalmology

    1-24 of 8826 1 2 3 4 ... 366 367 368 »
    1. Early microvascular retinal changes in optical coherence tomography angiography in patients with type 1 diabetes mellitus

      Early microvascular retinal changes in optical coherence tomography angiography in patients with type 1 diabetes mellitus

      Purpose Diabetic retinopathy (DR) can lead to significant vision loss and blindness and has a particularly high prevalence in patients with type 1 diabetes (DM1). In this study, we investigate quantitative differences in optical coherence tomography angiography (OCTA) data between DM1 patients with no or mild signs of retinopathy and non-diabetic subjects. Methods Optical coherence tomography angiography (OCTA) imaging was performed on DM1 patients with no or mild nonproliferative diabetic retinopathy and healthy, age-matched controls. Parafoveal vessel density and foveal avascular zone (FAZ) area in the deep capillary plexus (DCP) and superficial capillary plexus (SCP) were calculated with automated quantification ...

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    2. OCT imaging of retina useful in detecting glaucoma ‘masqueraders’

      OCT imaging of retina useful in detecting glaucoma ‘masqueraders’

      Optic nerve and macular optical coherence tomography can be helpful in distinguishing between glaucoma and glaucoma masqueraders, according to researchers. Researchers reported a case series of 4 patients and their spectral-domain OCT findings with retinal disease or nonglaucomatous optic neuropathy, who presented with suspected or previously diagnosed normal-tension glaucoma. The first patient was found to have marked diffuse retinal nerve fiber layer (RNFL) and macular thinning on OCT due to cancer-associated retinopathy, researchers wrote. The 76-year-old woman was referred after cataract surgery failed to relieve her symptoms of progressive vision loss. The second patient showed deep focal inferotemporal RNFL loss ...

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    3. History of Intraoperative OCT

      History of Intraoperative OCT

      Pars plana vitrectomy is almost a half-century old, and the earliest probes were powered by batteries, said Cynthia A. Toth, MD, the Joseph A.C. Wadsworth professor of ophthalmology at Duke University Medical Center. OCT imaging has “revolutionized our pre- and postoperative assessment,” she said, “but while our tools have advanced, our microscopes have not.” Although OCT granted surgeons the ability to visualize anatomical abnormalities in the retina, surgeons returned to en face OCT-free views during surgery. Dr. Toth noted there are “three staged developments in OCT – stage A was intraoperative OCT,” where a two-dimensional view outside the microscope gave ...

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    4. Retinal structure assessed by OCT as a biomarker of brain development in children born small for gestational age

      Retinal structure assessed by OCT as a biomarker of brain development in children born small for gestational age

      Purpose To identify differences in neuronal tissue from retinal and brain structures in children born small for gestational age (SGA) with no abnormality in neonatal brain ultrasonography and no previous neurological impairment, and to evaluate the relationship between retinal structure and brain changes in school-age children born SGA. Methods Two cohorts of children were recruited: 25 children born SGA and 25 children born with an appropriate birth weight according to gestational age. All the children underwent an ophthalmic examination, which included retinal imaging using spectral-domain optical coherence tomography, and a brain MRI. MRI images were automatically segmented and global and ...

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    5. Automated feature extraction for retinal vascular biometry in zebrafish using OCT angiography

      Automated feature extraction for retinal vascular biometry in zebrafish using OCT angiography

      Zebrafish have been identified as an ideal model for angiogenesis because of anatomical and functional similarities with other vertebrates. The scale and complexity of zebrafish assays are limited by the need to manually treat and serially screen animals, and recent technological advances have focused on automation and improving throughput. Here, we use optical coherence tomography (OCT) and OCT angiography (OCT-A) to perform noninvasive, in vivo imaging of retinal vasculature in zebrafish. OCT-A summed voxel projections were low pass filtered and skeletonized to create an en face vascular map prior to connectivity analysis. Vascular segmentation was referenced to the optic nerve ...

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    6. Semiautomated segmentation and analysis of retinal layers in three-dimensional spectral-domain optical coherence tomography images of patients with atrophic age-related macular degeneration

      Semiautomated segmentation and analysis of retinal layers in three-dimensional spectral-domain optical coherence tomography images of patients with atrophic age-related macular degeneration

      Historically, regular drusen and geographic atrophy (GA) have been recognized as the hallmarks of nonneovascular age-related macular degeneration (AMD). Recent imaging developments have revealed another distinct nonneovascular AMD phenotype, reticular pseudodrusen (RPD). We develop an approach to semiautomatically quantify retinal surfaces associated with various AMD lesions (i.e., regular drusen, RPD, and GA) in spectral domain (SD) optical coherence tomography (OCT) images. More specifically, a graph-based algorithm was used to segment multiple retinal layers in SD-OCT volumes. Varying surface feasibility constraints based on the presegmentation were applied on the double-surface graph search to refine the surface segmentation. The thicknesses of ...

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    7. Omega Sign: A Distinct Optical Coherence Tomography Finding in Macular Combined Hamartoma of Retina and Retinal Pigment Epithelium

      Omega Sign: A Distinct Optical Coherence Tomography Finding in Macular Combined Hamartoma of Retina and Retinal Pigment Epithelium

      BACKGROUND AND OBJECTIVE: To report a distinct optical coherence tomography (OCT) appearance of macular combined hamartoma of retina and retinal pigment epithelium (CHRRPE). \ PATIENTS AND METHODS: This is a retrospective case series of four eyes of four patients with macular CHRRPE who were assessed with the help of color fundus photographs, swept-source OCT (SS-OCT), and fundus fluorescein angiography wherever required. RESULTS: All four patients presented with decreased visual acuity. SS-OCT in all patients showed adherent epiretinal membrane (ERM) and localized thickening of underlying retina. An omega-shaped disorganization of inner retinal layers was seen bounded posteriorly by the outer plexiform layer ...

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    8. Optical Coherence Tomography Angiography of Paracentral Acute Middle Maculopathy Associated With Primary Antiphospholipid Syndrome

      Optical Coherence Tomography Angiography of Paracentral Acute Middle Maculopathy Associated With Primary Antiphospholipid Syndrome

      The authors present the first case of paracentral acute middle maculopathy as a manifestation of primary antiphospholipid syndrome (APS) with multimodal imaging, including optical coherence tomography angiography (OCTA). The association between APS and ophthalmic sequela is well-known. Recent advances in multimodal imaging, specifically OCTA, allow for better characterization of the mechanism and extent by which retinal arterial thrombosis can cause vision loss. Using advanced imaging modalities, the authors provide a comprehensive assessment of retinal ischemia, which showed not only localized capillary occlusion, but also ischemia of the deep retinal capillary plexus.

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    9. Four-dimensional Microscope-Integrated Optical Coherence Tomography to Visualize Suture Depth in Strabismus Surgery

      Four-dimensional Microscope-Integrated Optical Coherence Tomography to Visualize Suture Depth in Strabismus Surgery

      The authors report the use of swept-source microscope-integrated optical coherence tomography (SS-MIOCT), capable of live four-dimensional (three-dimensional across time) intraoperative imaging, to directly visualize suture depth during lateral rectus resection. Key surgical steps visualized in this report included needle depth during partial and full-thickness muscle passes along with scleral passes.

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    10. Detection of Minimally Visible Recurrent Retinoblastoma by Hand-held Spectral-Domain Optical Coherence Tomography

      Detection of Minimally Visible Recurrent Retinoblastoma by Hand-held Spectral-Domain Optical Coherence Tomography

      A 2-month-old male infant with bilateral familial retinoblastoma was treated with intravenous chemotherapy and focal adjuvant therapy. At 5 months of follow-up, fundus examination and ultrasonography disclosed no recurrence; however, hand-held spectral-domain optical coherence tomography (SD-OCT) demonstrated subclinical recurrence within a previous regression scar. Subsequent treatment led to flat scar. Hand-held SD-OCT can be a useful tool for detection of subclinical recurrent retinoblastoma.

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    11. Using OCT with your diabetes patients

      Using OCT with your diabetes patients

      Patients with diabetes may present a variety of interesting findings best unveiled by use of spectral domain optical coherence tomography (SD-OCT). OCT is one of the best way to assess patients for the presence of diabetic macular edema (DME). It is extremely useful for monitoring responses to treatments such as anti-VEGF injections, grid or focal laser, intravitreal steroids, or any combination thereof in patients with DME involving or threatening the fovea (center-involved DME). However, detecting and monitoring increased retinal thickness associated with diabetes is not the only relevant anatomical feature best visualized and appreciated with OCT. Let’s consider a ...

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    12. Master/slave based optical coherence tomography for in-vivo, real-time, long axial imaging range of the anterior segment

      Master/slave based optical coherence tomography for in-vivo, real-time, long axial imaging range of the anterior segment

      In this report, we demonstrate that in a coherence revival (CR) based swept source optical coherence tomography (SSOCT) set-up, real-time cross-sectional long-range images can be produced via the Master Slave (MS) method. The total tolerance of the MS method to nonlinear tuning, to dispersion in the interferometer and to dispersion due to the laser cavity, makes the MS ideally suited to the practice of coherence revival. In addition, enhanced versatility is allowed by the MS method in displaying shorter axial range images than that determined by the digital sampling of the data. This brings an immediate improvement in the speed ...

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    13. Motion-corrected en face optical coherence tomography angiography imaging based on the modified Lissajous scanning pattern

      Motion-corrected en face optical coherence tomography angiography imaging based on the modified Lissajous scanning pattern

      A motion - corrected en face optical coherence tomography angiography (OCT - A) imaging method is presented in this paper. This method was designed to correct eye motion artifacts in en face OCT - A images automatically using a software. A modified Lissajous scanning pattern, which is compatible with OCT - A, was adopted as the scanning protocol for the optical coherence tomography (OCT) machine to obtain the OCT - A data. The OCT - A data was then processed using motion correction algorithm that was tailored for the modified Lissajous scanning pattern to correct the eye motion artifacts in the en face plane. The OCT ...

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    14. Modular multimodal swept-source spectrally encoded scanning laser ophthalmoscopy and optical coherence tomography scan-head for surgical microscope-integrated and slit-lamp imaging

      Modular multimodal swept-source spectrally encoded scanning laser ophthalmoscopy and optical coherence tomography scan-head for surgical microscope-integrated and slit-lamp imaging

      anning laser ophthalmoscopy (SLO) and optical coherence tomography (OCT) enable noninvasive in vivo diagnostic imaging and provide complementary en face and depth-resolved visualization of ophthalmic structures, respectively. We previously demonstrated concurrent multimodal swept-source spectrally encoded scanning laser ophthalmoscopy and OCT (SS-SESLO-OCT) at 1060 nm using a swept-source and double clad fiber coupler. Here, we present system enhancements and novel designs for a modular SS-SESLO-OCT scan-head that can be coupled to ophthalmic surgical microscope-integrated and slit-lamp imaging optics. Multimodal SS-SESLO-OCT was demonstrated using a custom-built swept-source OCT engine with a 200 kHz 1060 nm source that was optically buffered for concurrent ...

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    15. Quantitative optical coherence tomography angiography of the peripapillary circulation in glaucoma

      Quantitative optical coherence tomography angiography of the peripapillary circulation in glaucoma

      The cause of glaucoma, a disease defined by degeneration of retinal ganglion cells associated with cupping of the optic nerve head (ONH) and progressive vision loss, continues to be debated despite numerous advances in ophthalmic imaging and diagnostics. Although elevated intraocular pressure is often implicated, many studies, using a variety of imaging techniques including plain fundus photography, fluorescein angiography, laser Doppler flowmetry, and color Doppler ultrasound (1-4), have suggested that insufficiencies of ONH circulation may play a role in glaucoma pathogenesis. While all of these imaging modalities have been informative, each has a set of limitations, including low spatial resolution ...

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    16. Detailed Vascular Anatomy of the Human Retina by Projection-Resolved Optical Coherence Tomography Angiography

      Detailed Vascular Anatomy of the Human Retina by Projection-Resolved Optical Coherence Tomography Angiography

      Optical coherence tomography angiography (OCTA) is a noninvasive method of 3D imaging of the retinal and choroidal circulations. However, vascular depth discrimination is limited by superficial vessels projecting flow signal artifact onto deeper layers. The projection-resolved (PR) OCTA algorithm improves depth resolution by removing projection artifact while retaining in-situ flow signal from real blood vessels in deeper layers. This novel technology allowed us to study the normal retinal vasculature in vivo with better depth resolution than previously possible. Our investigation in normal human volunteers revealed the presence of 2 to 4 distinct vascular plexuses in the retina, depending on location ...

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    17. Evaluation of macular vascular abnormalities identified by optical coherence tomography angiography in sickle cell disease

      Evaluation of macular vascular abnormalities identified by optical coherence tomography angiography in sickle cell disease

      Purpose To evaluate macular vascular flow abnormalities identified by optical coherence tomography angiography (OCT-A) in patients with various sickle cell genotypes. Design Prospective, observational case series. Methods This is a single institution case series of adult patients with various sickle cell genotypes. All patients underwent macular OCT-A (Avanti RTVue XR, Optovue Inc, Fremont, CA). Images were analyzed qualitatively for areas of flow loss and quantitatively for measures of foveal avascular area, parafoveal flow, and vascular density. The findings were compared by sickle cell genotype and retinopathy stage and correlated to retinal thickness and visual acuity. Results OCT-A scans of 82 ...

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    18. Optical coherence tomography segmentation analysis in relapsing remitting versus progressive multiple sclerosis

      Optical coherence tomography segmentation analysis in relapsing remitting versus progressive multiple sclerosis

      Introduction Optical coherence tomography (OCT) with retinal segmentation analysis is a valuable tool in assessing axonal loss and neuro-degeneration in multiple sclerosis (MS) by in-vivo imaging, delineation and quantification of retinal layers. There is evidence of deep retinal involvement in MS beyond the inner retinal layers. The ultra-structural retinal changes in MS in different MS phenotypes can reflect differences in the pathophysiologic mechanisms. There is limited data on the pattern of deeper retinal layer involvement in progressive MS (PMS) versus relapsing remitting MS (RRMS). We have compared the OCT segmentation analysis in patients with relapsing-remitting MS and progressive MS. Methods ...

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    19. Detailed Phenotyping and Characterization of Choroidal Morphological and Vascular Features in Young Men with High Myopia Using Spectral-Domain Optical Coherence Tomography

      Detailed Phenotyping and Characterization of Choroidal Morphological and Vascular Features in Young Men with High Myopia Using Spectral-Domain Optical Coherence Tomography

      Purpose To describe detailed morphological and vascular features of the choroid in eyes with high myopia. Design Cross-sectional study. Methods 515 eyes of young men (mean age 21.59±1.15) years) with high myopia (defined as -6.0 D or worse, mean spherical equivalent -8.66±2.00 D) and 88 controls with emmetropia in both eyes underwent choroidal imaging using spectral domain optical coherence tomography with enhanced depth imaging (EDI-OCT). Raw OCT images were loaded on a custom-written application on MATLAB that enabled delineation for detailed morphological and vascular analyses, including the distance of thickest point from the ...

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    20. Spectral Domain Optical Coherence Tomography Angiography in Stargardt's Macular Dystrophy

      Spectral Domain Optical Coherence Tomography Angiography in Stargardt's Macular Dystrophy

      Stargardt's macular dystrophy (SMD) is the most common form of hereditary recessive macular dystrophy, seen in approximately 1 in 10 000 people, and accounts for 7% of all retinal degenerations. 1 The pathophysiology is a well-described mutation in the ABCA4 gene, resulting in the accumulation of lipofuscin (modified residues of incompletely digested photoreceptor outer segments), retinal pigment epithelium (RPE) cell death, and irreversible progressive atrophy in the macula. 2 Optical coherence tomography angiography (OCTA) is a unique imaging technique that provides high-resolution imaging of capillary networks and allows for segmentation of different layers of retinal and choroidal vasculature. 3 ...

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    21. Involuntary Eye Motion Correction in Retinal Optical Coherence Tomography: Hardware or Software Solution?

      Involuntary Eye Motion Correction in Retinal Optical Coherence Tomography: Hardware or Software Solution?

      In this paper, we review state-of-the-art techniques to correct eye motion artifacts in Optical Coherence Tomography (OCT) imaging. The methods for eye motion artifact reduction can be categorized into two major classes: 1) hardware-based techniques and 2) software-based techniques. In the first class, additional hardware is mounted onto the OCT scanner to gather information about the eye motion patterns during OCT data acquisition. This information is later processed and applied to the OCT data for creating an anatomically correct representation of the retina, either in an offline or online manner. In software based techniques, the motion patterns are approximated either ...

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    22. PREDICTIVE FACTORS FOR DEVELOPMENT OF NEOVASCULAR AGE-RELATED MACULAR DEGENERATION: A Spectral-Domain Optical Coherence Tomography Study

      PREDICTIVE FACTORS FOR DEVELOPMENT OF NEOVASCULAR AGE-RELATED MACULAR DEGENERATION: A Spectral-Domain Optical Coherence Tomography Study

      Purpose: To investigate the risk factors predictive for the development of neovascular age-related macular degeneration (NVAMD) by means of spectral-domain optical coherence tomography. Methods: Retrospective study of 73 eyes graded Stage 2 and Stage 3 according to the AMD International Grading System with minimum follow-up of 24 months. Drusenoid pigment epithelial detachment, hyperreflective foci, external limiting membrane, inner ellipsoid band, and retinal pigment epithelium integrity were analyzed at baseline and last follow-up. Binary logistic regression model analyzed significant predictors of neovascular conversion. Results: The discontinuity of external limiting membrane, inner ellipsoid band, and retinal pigment epithelium bands were significantly more ...

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    23. Choroidal Vessel Diameters in Pseudoexfoliation and Pseudoexfoliation Glaucoma Analyzed Using Spectral-Domain Optical Coherence Tomography

      Choroidal Vessel Diameters in Pseudoexfoliation and Pseudoexfoliation Glaucoma Analyzed Using Spectral-Domain Optical Coherence Tomography

      Abstract Purpose of the Study: The purpose of the study was to analyze choroidal vessel diameters in pseudoexfoliation (PXF) and pseudoexfoliation glaucoma (PXFG) using spectral-domain optical coherence tomography (SD-OCT). Materials and Methods: Fifty patients (100 eyes) with PXF and PXFG who underwent high-definition 1-line raster SD-OCT imaging at New England Eye Center, Boston, were retrospectively identified and divided into unilateral PXFG (26 patients, 52 eyes), unilateral PXF (4 patients, 8 eyes), bilateral PXFG (4 patients, 8 eyes), and bilateral PXF (16 patients, 32 eyes). Eyes with concomitant chorioretinal pathology, history of shunting/filtering for glaucoma, and significant anisometropia were excluded ...

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