1. 1-24 of 301 1 2 3 4 ... 11 12 13 »
    1. Vulnerability Zone of Glaucoma Progression in Combined Wide-field Optical Coherence Tomography Event-based Progression Analysis

      Vulnerability Zone of Glaucoma Progression in Combined Wide-field Optical Coherence Tomography Event-based Progression Analysis

      Purpose : To investigate the spatial characteristics and patterns of structural progression using the combined retinal nerve fiber layer (RNFL) and ganglion cell–inner plexiform layer event-based progression analysis feature provided by the Guided Progression Analysis (GPA) software of spectral-domain optical coherence tomography. Methods : In this retrospective observational study, we evaluated 89 patients with open-angle glaucoma showing clinically confirmed structural progression within a minimum follow-up period of 3 years. For each eye, the RNFL and ganglion cell–inner plexiform layer GPA data were extracted from serial spectral-domain optical coherence tomography (HD-OCT 4000, Carl Zeiss Meditec, Inc., Dublin, CA) data from 2012 ...

      Read Full Article
    2. Segmented Macular Layer Volumes from Spectral Domain Optical Coherence Tomography in 184 Adult Twins: Associations With Age and Heritability

      Segmented Macular Layer Volumes from Spectral Domain Optical Coherence Tomography in 184 Adult Twins: Associations With Age and Heritability

      Purpose : To investigate segmented macular layer volumes from a healthy adult twin cohort (TwinsUK), exploring changes with age and heritability. Methods : Macular spectral domain optical coherence tomography images were acquired from monozygotic (MZ) and dizygotic (DZ) twins in a cross-sectional study. The following layer volumes were derived for circles of 3 and 6 mm diameter around the foveal center, using automated segmentation software: retinal nerve fiber layer (RNFL), ganglion cell–inner plexiform layer (GCIPL), inner nuclear layer (INL), outer plexiform layer (OPL), outer nuclear layer (ONL), photoreceptors (PR), retinal pigment epithelium (RPE), and total retinal volume (TRV). Correlation coefficients (intereye ...

      Read Full Article
    3. Identifying Microvascular and Neural Parameters Related to the Severity of Diabetic Retinopathy Using Optical Coherence Tomography Angiography

      Identifying Microvascular and Neural Parameters Related to the Severity of Diabetic Retinopathy Using Optical Coherence Tomography Angiography

      Purpose : To identify microvascular and neural parameters related to the severity of diabetic retinopathy (DR) by using optical coherence tomography angiography in patients with type 2 diabetes. Methods : This cross-sectional study included 110 eyes (63 patients) with no DR, 46 eyes (33 patients) with mild nonproliferative DR, 36 eyes (23 patients) with moderate nonproliferative DR, 36 eyes (22 patients) with severe nonproliferative DR, and 31 eyes (19 patients) with proliferative DR. The optical coherence tomography angiography images were processed to quantify the foveal avascular zone parameters, macular vessel density (VD), retinal thickness, peripapillary VD, retinal nerve fiber layer thickness, and ...

      Read Full Article
    4. Morphologic Features of Crystalline Lens in Patients with Primary Angle Closure Disease Observed by CASIA 2 Optical Coherence Tomography

      Morphologic Features of Crystalline Lens in Patients with Primary Angle Closure Disease Observed by CASIA 2 Optical Coherence Tomography

      Purpose : To investigate the morphologic features of crystalline lens in primary angle closure disease (PACD) by the swept-source anterior segment optical coherence tomography. Methods : This cross-sectional observational study included 125 consecutive eyes from 125 patients who underwent anterior segment optical coherence tomography (CASIA 2, Tomey, Nagoya, Japan) examination, including 38 eyes of normal controls, 57 eyes of PAC suspects (PACS), and 30 eyes with PAC or PAC glaucoma (PACG). Crystalline lens parameters were compared among the three groups. Spearman correlation analysis and multiple linear regression models were performed to evaluate the relationships between the lens parameters and related factors. Results ...

      Read Full Article
    5. Acute Hyperglycemia Reverses Neurovascular Coupling During Dark to Light Adaptation in Healthy Subjects on Optical Coherence Tomography Angiography

      Acute Hyperglycemia Reverses Neurovascular Coupling During Dark to Light Adaptation in Healthy Subjects on Optical Coherence Tomography Angiography

      Purpose : To test the hypothesis that hyperglycemia perturbs neurovascular\ coupling and compromises retinal vascular response during transition from dark to light in healthy subjects using optical coherence tomography angiography (OCTA). Methods : Ten eyes of 10 healthy subjects were tested, first during fasting and then after receiving a 75-g oral glucose solution. In both sessions, OCTA imaging was done in the dark-adapted state and at 50 seconds, 2 minutes, 5 minutes, and 15 minutes of ambient light. Parafoveal vessel density (VD) and adjusted flow index (AFI) were calculated for the superficial capillary plexus (SCP), middle capillary plexus (MCP), and deep capillary ...

      Read Full Article
    6. Caffeine Delays Retinal Neurovascular Coupling during Dark to Light Adaptation in Healthy Eyes Revealed by Optical Coherence Tomography Angiography

      Caffeine Delays Retinal Neurovascular Coupling during Dark to Light Adaptation in Healthy Eyes Revealed by Optical Coherence Tomography Angiography

      Purpose : The purpose of this study was to investigate the acute effects of caffeine on retinal hemodynamics during dark to light adaptation using optical coherence tomography angiography (OCTA). Methods : Thirteen healthy individuals (13 eyes) underwent OCTA imaging after dark adaptation and at repeated intervals during the transition to ambient light in two imaging sessions: control and after ingesting 200 mg of caffeine. We analyzed the parafoveal vessel density (VD) and adjusted flow index (AFI) of the superficial capillary plexus (SCP), middle capillary plexus (MCP), and deep capillary plexus (DCP), as well as the vessel length density (VLD) of the SCP ...

      Read Full Article
    7. Optical Coherence Tomography Angiography of Perilimbal Vasculature in Port-Wine Stain and Sturge-Weber Syndrome Patients

      Optical Coherence Tomography Angiography of Perilimbal Vasculature in Port-Wine Stain and Sturge-Weber Syndrome Patients

      Purpose : To evaluate episcleral vasculature in corneal limbus with optical coherence tomography angiography (OCTA) in normal controls, port-wine stain (PWS) patients, and Sturge-Weber syndrome (SWS) patients. Methods : Unilateral eyes from 18 normal controls (25.41 ± 4.00 years), 16 PWS patients (21.35 ± 11.05 years), and 8 SWS patients with ipsilateral late-onset glaucoma (22.13 ± 7.82 years). Each subject underwent slit-lamp examination, applanation tonometry, and OCTA. All OCTA scans were performed using an OCTA system operating at a wavelength of 1050-nm in four quadrants (superior, inferior, nasal, and temporal). The scans were delineated into conjunctival and episcleral layers ...

      Read Full Article
    8. Features of the Choroidal Structures in Myopic Children Based on Image Binarization of Optical Coherence Tomography

      Features of the Choroidal Structures in Myopic Children Based on Image Binarization of Optical Coherence Tomography

      Purpose : To evaluate the features of the choroidal structures in the eyes of myopic children obtained by enhanced depth imaging optical coherence tomography (EDI-OCT). Methods : Ninety-six myopic children with low to moderate myopia (spherical equivalent refractive error [SER], –5.75 to –1.00 diopter) were included in this cross-sectional study. Ocular biometrics were measured using an optical low-coherence reflectometry device. Data of the choroidal structures extracted from a 7500-µm cross-sectional arc of the choroid extending from the temporal optic disc margin, including the total choroidal area, luminal area, stromal area, and choroidal vascularity index, were determined by image binarization ...

      Read Full Article
    9. Association Between Clinical Biomarkers and Optical Coherence Tomography Angiography Parameters in Type 2 Diabetes Mellitus

      Association Between Clinical Biomarkers and Optical Coherence Tomography Angiography Parameters in Type 2 Diabetes Mellitus

      Purpose : To investigate the clinical significance of the changes in the macular microvasculature in patients with diabetes mellitus type 2 without diabetic retinopathy. Methods : Fifty-five patients with diabetes mellitus type 2 without diabetic retinopathy and 48 healthy individuals were enrolled in a prospective cross-sectional study. We identified the changes of optical coherence tomography angiography parameters (foveal avascular zone [FAZ] area and circularity, vessel density, and perfusion index) of the 6 × 6-mm macular scan. Correlation and multiple regression analyses were performed between optical coherence tomography angiography parameters and previously known diabetes mellitus type 2-related demographic and systemic characteristics, and serum biochemical ...

      Read Full Article
    10. Longitudinal Changes in Retinal Blood Flow in a Feline Retinal Vein Occlusion Model as Measured by Doppler Optical Coherence Tomography and Optical Coherence Tomography Angiography

      Longitudinal Changes in Retinal Blood Flow in a Feline Retinal Vein Occlusion Model as Measured by Doppler Optical Coherence Tomography and Optical Coherence Tomography Angiography

      Purpose : We aimed to observe longitudinal changes in retinal blood flow (RBF) and structural transformations in capillaries using Doppler optical coherence tomography (DOCT) and optical coherence tomography angiography (OCTA) in a feline retinal blood occlusion (RVO) model. Methods : RVO was induced by argon green laser photocoagulation (PC) in six eyes of six cats. RBF was measured at a first-order retinal artery and vein by a DOCT flowmeter, and structural changes in the capillaries around the occluded vessels (12 × 12 and 3 × 3 mm) were assessed by OCTA before (at baseline); immediately after PC; and on days 1, 4, 7, and ...

      Read Full Article
    11. Changes in Retinal Blood Flow in Response to an Experimental Increase in IOP in Healthy Participants as Assessed With Doppler Optical Coherence Tomography

      Changes in Retinal Blood Flow in Response to an Experimental Increase in IOP in Healthy Participants as Assessed With Doppler Optical Coherence Tomography

      Purpose : Blood flow autoregulation is an intrinsic mechanism of the healthy retinal vasculature to keep blood flow constant when ocular perfusion pressure (OPP) is changed. In the present study, we set out to investigate retinal blood flow in response to an experimental decrease in OPP in healthy participants using Doppler optical coherence tomography. Methods : Fifteen healthy participants aged between 22 and 31 years (mean, 27 ± 3 years) were included in the present open study. IOP was increased stepwise via the suction cup method to induce a decrease in OPP. Retinal blood flow in arteries and veins was assessed using a ...

      Read Full Article
    12. In Vivo Imaging of Schlemm's Canal and Limbal Vascular Network in Mouse Using Visible-Light OCT

      In Vivo Imaging of Schlemm's Canal and Limbal Vascular Network in Mouse Using Visible-Light OCT

      Purpose : To validate the ability of visible-light optical coherence tomography (vis-OCT) in imaging the full Schlemm's canal (SC) and its surrounding limbal vascular network in mice in vivo through a compound circumlimbal scan. Methods : We developed an anterior segment vis-OCT system and a compound circumlimbal scanning method, which montages eight rotated raster scans. We calibrated the circumlimbal scan geometry using a three-dimensional printed phantom eyeball before imaging wild-type C57BL/6J mice. We measured SC size by segmenting SC cross sections from vis-OCT B-scan images and imaged the limbal microvascular network using vis-OCT angiography (vis-OCTA). To introduce changes in SC ...

      Read Full Article
    13. Angiographic Risk Features of Branch Retinal Vein Occlusion Onset as Determined by Optical Coherence Tomography Angiography

      Angiographic Risk Features of Branch Retinal Vein Occlusion Onset as Determined by Optical Coherence Tomography Angiography

      Purpose : Examine associations between the vasculature at arteriovenous (AV) crossings and the onset of branch retinal vein occlusion (BRVO). Methods : We included 78 patients with major BRVO, 35 patients with macular BRVO, and 110 controls without BRVO and determined the vessel positions at AV crossings, where the first- or second-order branches of the retinal veins associate, using a viewing angle of 12 × 12 mm 2 in optical coherence tomography angiography (OCTA). Results : We reviewed 1349 and 1276 AV crossings in BRVO patients and control subjects, respectively. The proportions of venous overcrossing were 26.5%, 28.6%, and 26.8% at ...

      Read Full Article
    14. Global Analysis of Macular Choriocapillaris Perfusion in Dry Age-Related Macular Degeneration using Swept-Source Optical Coherence Tomography Angiography

      Global Analysis of Macular Choriocapillaris Perfusion in Dry Age-Related Macular Degeneration using Swept-Source Optical Coherence Tomography Angiography

      Purpose : Swept-source optical coherence tomography angiography (SS-OCTA) was used to investigate if the clinical stage of dry age-related macular degeneration (AMD) was correlated with global and regional macular choriocapillaris (CC) perfusion. Methods : In this retrospective, cross-sectional study, 6 × 6-mm SS-OCTA images from eyes with early, intermediate, and advanced dry AMD (56 eyes, 41 patients) were analyzed using algorithms described in the literature to assess regional flow deficit percentage (FD%) and average flow deficit size. Regions were defined by concentric areas centered on the fovea: a 1-mm-diameter area, 3-mm-diameter ring, 5-mm-diameter area, 5-mm-diameter ring, and 6 × 6-mm whole image. Data were ...

      Read Full Article
    15. The Relationship Between Ambient Atmospheric Fine Particulate Matter (PM2.5) and Glaucoma in a Large Community Cohort

      The Relationship Between Ambient Atmospheric Fine Particulate Matter (PM2.5) and Glaucoma in a Large Community Cohort

      Purpose : Glaucoma is more common in urban populations than in others. Ninety percent of the world's population are exposed to air pollution above World Health Organization (WHO) recommended limits. Few studies have examined the association between air pollution and glaucoma. Methods : Questionnaire data, ophthalmic measures, and ambient residential area air quality data for 111,370 UK Biobank participants were analyzed. Particulate matter with an aerodynamic diameter < 2.5 μm (PM 2.5 ) was selected as the air quality exposure of interest. Eye measures included self-reported glaucoma, intraocular pressure (IOP), and average thickness of macular ganglion cell–inner plexiform layer ...

      Read Full Article
    16. Retinal and Choroidal Perfusion Status in the Area of Laser Scars Assessed With Swept-Source Optical Coherence Tomography Angiography

      Retinal and Choroidal Perfusion Status in the Area of Laser Scars Assessed With Swept-Source Optical Coherence Tomography Angiography

      Purpose : To evaluate the perfusion status of the retina and choriocapillaris in the area of laser scars on swept-source optical coherence tomography angiography (OCTA) images of eyes previously treated with panretinal photocoagulation (PRP). Methods : Cross-sectional exploratory analysis of swept-source OCTA images, which were retrospectively reviewed for laser scars. The appearance of the capillary networks in the area of previous laser were evaluated following a three-step grading system (normal/sparse/missing capillary network). The superficial and deep capillary plexus of the retina and the choriocapillaris were graded separately. Results : A total of 3140 laser scars in 54 eyes of 31 patients ...

      Read Full Article
    17. Characteristics of Posterior Precortical Vitreous Pockets and Cloquet's Canal in Patients with Myopia by Swept-Source Optical Coherence Tomography

      Characteristics of Posterior Precortical Vitreous Pockets and Cloquet's Canal in Patients with Myopia by Swept-Source Optical Coherence Tomography

      Purpose : To describe the morphological features of posterior precortical vitreous pockets (PPVP) and Cloquet's Canal in patients with myopia using swept-source optical coherence tomography (SS OCT). Methods : A total of 96 eyes of 51 volunteers (range, 5–18 years) were enrolled in this study, and all individuals underwent OCT (Optovue Inc., Fremont, CA, USA) examinations. From the collected PPVPs images, the widths and heights of the PPVPs were measured, and connections between PPVPs and Cloquet's Canal were identified. The PPVPs widths and heights, width:height ratios and proportions of connections were compared among different age (5–8, 9 ...

      Read Full Article
    18. Macular Vessel Density Measured With Optical Coherence Tomography Angiography and Its Associations in a Large Population-Based Study

      Macular Vessel Density Measured With Optical Coherence Tomography Angiography and Its Associations in a Large Population-Based Study

      Purpose : We investigate macular perfusion and the systemic and ocular associations in a population-based setting. Methods : In this cross-sectional study, 2018 adults residing in Hong Kong underwent detailed ophthalmic examinations after consenting to participate. Macular perfusion was measured with optical coherence tomography angiography (OCTA) using the split-spectrum amplitude decorrelation angiography algorithm. The parafoveal flow index and vessel area density were quantified using automated custom-built software. Results : Of the 2018 participants, the OCTA measurements were available for 1940, and 1631 (84.1%) had good quality scans. The right eyes of these 1631 participants (43.1% men) were included for final analysis ...

      Read Full Article
    19. Association Between Perifoveal Drusen Burden Determined by OCT and Genetic Risk in Early and Intermediate Age-Related Macular Degeneration

      Association Between Perifoveal Drusen Burden Determined by OCT and Genetic Risk in Early and Intermediate Age-Related Macular Degeneration

      Purpose : The purpose of this study was to determine associations between macular drusen parameters derived from an automatic optical coherence tomography (OCT) algorithm, nonadvanced age-related macular degeneration (AMD) stage, and genetic variants. Methods : Eyes classified as early or intermediate AMD with OCT imaging and genetic data were selected ( n = 239 eyes). Drusen area and volume measurements were estimated using the Zeiss Cirrus advanced retinal pigment epithelium analysis algorithm in a perifoveal zone centered on the fovea. Associations between drusen measurements and common genetic variants in the complement and high-density lipoprotein (HDL) lipid pathways and the ARMS2/HTRA1 variant were calculated ...

      Read Full Article
    20. Analysis of Hyperreflective Dots Within the Central Fovea in Healthy Eyes Using En Face Optical Coherence Tomography

      Analysis of Hyperreflective Dots Within the Central Fovea in Healthy Eyes Using En Face Optical Coherence Tomography

      Purpose : The purpose of this retrospective study was to describe and quantify superficial hyperreflective dots within the central fovea and correlate them with age, using en face and cross-sectional B-scan optical coherence tomography (OCT). Methods : Healthy eyes, evaluated with a spectral domain instrument (primary cohort) at the Stein Eye Institute (UCLA) and with a swept source instrument (secondary cohort) at the Vitreous Retina Macula Consultants of New York, were included in this study. En face OCT images (3 × 3 mm) segmented at the level of the superior vascular plexus were acquired, and hyperreflective dots in the foveal avascular zone were ...

      Read Full Article
    21. Retinal Nonperfusion Relationship to Arteries or Veins Observed on Widefield Optical Coherence Tomography Angiography in Diabetic Retinopathy

      Retinal Nonperfusion Relationship to Arteries or Veins Observed on Widefield Optical Coherence Tomography Angiography in Diabetic Retinopathy

      Purpose : To evaluate whether retinal capillary nonperfusion is found predominantly adjacent to arteries or veins in eyes with diabetic retinopathy (DR). Methods : Sixty-three eyes from 44 patients with proliferative DR (PDR) or non-PDR (NPDR) were included. Images (12 × 12-mm) foveal-centered optical coherence tomography (OCT) angiography (OCTA) images were taken using the Zeiss Plex Elite 9000. In 37 eyes, widefield montages with five fixation points were also obtained. A semiautomatic algorithm that detects nonperfusion in full-retina OCT slabs was developed, and the percentages of capillary nonperfusion within the total image area were calculated. Retinal arteries and veins were manually traced. Based ...

      Read Full Article
    22. Effect of Choroidal Vessel Density on the Ellipsoid Zone and Visual Function in Retinitis Pigmentosa Using Optical Coherence Tomography Angiography

      Effect of Choroidal Vessel Density on the Ellipsoid Zone and Visual Function in Retinitis Pigmentosa Using Optical Coherence Tomography Angiography

      Purpose : We evaluate the effect of choroidal vessel density on the residual length of the ellipsoid zone (EZ) and visual function in patients with retinitis pigmentosa (RP) using optical coherence tomography angiography (OCTA). Methods : Fifty-three patients with RP ( n = 101 eyes) and 53 normal participants ( n = 76 eyes) were enrolled in this study. Patients with RP were assigned to three groups according to their best-corrected visual acuity (BCVA). All patients underwent ophthalmologic examinations, including BCVA, fundus examination performed with a slit-lamp using an indirect 90 diopter (D) lens, OCTA, full-field electroretinogram (ERG), and visual field. The choroidal vessel density in ...

      Read Full Article
    23. Histologic Correlation of Pig Retina Radial Stratification with Ultrahigh-Resolution Optical Coherence Tomography

      Histologic Correlation of Pig Retina Radial Stratification with Ultrahigh-Resolution Optical Coherence Tomography

      purpose. To compare ultrahigh-resolution optical coherence tomography (OCT) cross-sectional images of the pig retina with histology, to evaluate the potential of ultrahigh-resolution OCT for enhanced visualization of intra- and subretinal structures. methods. Ultrahigh-resolution OCT images were acquired with 1.4-μm axial × 3-μm transverse resolution from in vitro posterior eyecup preparations of the domestic pig. Frozen sections were obtained in precise alignment with OCT tomograms, by using major blood vessels as orientation markers and were counterstained with cresyl violet or unstained and examined by differential interference contrast microscopy. Micrographs from histologic sections were linearly scaled to correct for tissue ...

      Read Full Article
    24. A Pilot Optical Coherence Tomography Angiography Study on Superficial and Deep Capillary Plexus Foveal Avascular Zone in Patients With Beta-Thalassemia Major

      A Pilot Optical Coherence Tomography Angiography Study on Superficial and Deep Capillary Plexus Foveal Avascular Zone in Patients With Beta-Thalassemia Major

      Purpose : To investigate foveal avascular zone (FAZ) changes in the superficial (SCP) and deep (DCP) capillary plexuses in beta-thalassemia major (BTM) patients, as shown in optical coherence tomography angiography. Methods : Nonrandomized, comparative case series of 54 eyes of 27 BTM patients and 46 eyes of 23 healthy controls, utilizing an automated FAZ detection algorithm. Measurements included FAZ area and FAZ shape descriptors (convexity, circularity, and contour temperature). Results were compared between the two groups, and correlated to iron load and chelation therapy parameters. Results : SCP and DCP FAZ area were not significantly different between the control and BTM groups ( P ...

      Read Full Article
    1-24 of 301 1 2 3 4 ... 11 12 13 »
  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