1. 1-24 of 458 1 2 3 4 ... 17 18 19 »
    1. Surgical outcome and prognostic factors influencing visual acuity in myopic foveoschisis patients

      Surgical outcome and prognostic factors influencing visual acuity in myopic foveoschisis patients

      Background To analyze the optical coherence tomography (OCT) characteristics and visual outcome of vitrectomy in myopic foveoschisis (MF) patients and identify prognostic factors. Methods This study is a retrospective clinical cohort study in tertiary care hospital. Thirty-two eyes of 32 patients who underwent MF-related vitrectomy in were investigated retrospectively. Best-corrected visual acuity (BCVA) measured at 1 year post surgery and changes in central foveal thickness (CFT) and co-existing macular pathologies, such as foveal detachment (FD), lamellar holes, and macular holes were the main outcome measures. Prognostic factors were identified using multivariate linear regression analysis. Results Average BCVA (in logarithm of ...

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    2. Retinal fingerprints for precision profiling of cardiovascular risk

      Retinal fingerprints for precision profiling of cardiovascular risk

      Retinal microvascular changes are strongly linked to prevalent and incident cardiovascular disease. These changes can now be mapped with unparalleled accuracy using retinal optical coherence tomography. Novel retinal imaging, combined with the power of deep learning, might soon equip clinicians with unique and precise risk-assessment tools that enable truly individualized patient management.

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    3. Ocular biometry and refractive outcomes using two swept-source optical coherence tomography-based biometers with segmental or equivalent refractive indices

      Ocular biometry and refractive outcomes using two swept-source optical coherence tomography-based biometers with segmental or equivalent refractive indices

      This study compared the axial length (AL), central corneal thickness (CCT), anterior chamber depth (ACD), lens thickness (LT), mean anterior corneal radius of curvature (Rm), and postoperative refractive outcomes obtained from two different swept-source optical coherence biometers, the ARGOS (Movu, Nagoya, Japan), which uses the segmental refractive index for each segment, and the IOLMaster 700 (Carl Zeiss Meditec, Jena, Germany), which uses an equivalent refractive index for the entire eye. One hundred and six eyes of 106 patients with cataracts were included. The refractive outcomes using the Barrett Universal II, Haigis, Hoffer Q, and SRK/T formulas were evaluated. The ...

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    4. Line-Field Optical Coherence Tomography as a tool for In vitro characterization of corneal biomechanics under physiological pressures

      Line-Field Optical Coherence Tomography as a tool for In vitro characterization of corneal biomechanics under physiological pressures

      There has been a lot of interest in accurately characterising corneal biomechanical properties under intraocular pressure (IOP) to help better understand ocular pathologies that are associated with elevated IOP. This study investigates the novel use of Line-Field Optical Coherence Tomography (LF-OCT) as an elastographic tool for accurately measuring mechanical properties of porcine corneas based on volumetric deformation following varying IOPs. A custom-built LF-OCT was used to measure geometrical and corneal surface displacement changes in porcine corneas under a range of IOPs, from 0–60 mmHg. Corneal thickness, elastic properties and hysteresis were calculated as a function of pressure. In addition ...

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      Mentions: Yalin Zheng
    5. Optical Coherence Tomography Angiography Compared with Indocyanine Green Angiography in Central Serous Chorioretinopathy

      Optical Coherence Tomography Angiography Compared with Indocyanine Green Angiography in Central Serous Chorioretinopathy

      The purpose of this article is to compare optical coherence tomography angiography (OCTA) and indocyanine green angiography (ICGA) in patients with central serous chorioretinopathy (CSC). OCTA, ICGA and fluorescein angiography (FA) images of all enrolled patients were collected and compared. Abnormal areas were annotated on en face choriocapillaris OCTA and ICGA images and compared with each other. We found three main types of anomalies in choriocapillaris OCTA images: type A, coarse granulated high reflective area (61 eyes [92.4%]); type B, roundish dark halo around Type A (54 eyes [81.8%]); and type C, coarse granulated low reflective area (66 ...

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    6. Visualizing flow in an intact CSF network using optical coherence tomography: implications for human congenital hydrocephalus

      Visualizing flow in an intact CSF network using optical coherence tomography: implications for human congenital hydrocephalus

      Cerebrospinal fluid (CSF) flow in the brain ventricles is critical for brain development. Altered CSF flow dynamics have been implicated in congenital hydrocephalus (CH) characterized by the potentially lethal expansion of cerebral ventricles if not treated. CH is the most common neurosurgical indication in children effecting 1 per 1000 infants. Current treatment modalities are limited to antiquated brain surgery techniques, mostly because of our poor understanding of the CH pathophysiology. We lack model systems where the interplay between ependymal cilia, embryonic CSF flow dynamics and brain development can be analyzed in depth. This is in part due to the poor ...

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      Mentions: Yale University
    7. Impact of systemic vascular risk factors on the choriocapillaris using optical coherence tomography angiography in patients with systemic hypertension

      Impact of systemic vascular risk factors on the choriocapillaris using optical coherence tomography angiography in patients with systemic hypertension

      We investigated the characteristics of the choriocapillaris flow voids using optical coherence tomography angiography (OCTA) in 85 patients (164 eyes) with hypertension (mean ± SD age, 56 ± 11 years; 45% women; 20% poorly controlled BP; 16% diabetes) who are without ocular diseases and determined possible correlations with systemic vascular risk factors. Data on 24-hour ambulatory blood pressure (BP), serum creatinine, and urine microalbumin/creatinine ratio (MCR) were collected. Estimated glomerular filtration rate (eGFR) was calculated based on CKD-EPI Creatinine Equation. OCTA imaging (6 × 6 mm scans; AngioVue) with quantitative microvascular analysis of the choriocapillaris was performed. Linear regression was used to ...

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    8. Optical coherence tomography angiography for noninvasive evaluation of angiogenesis in a limb ischemia mouse model

      Optical coherence tomography angiography for noninvasive evaluation of angiogenesis in a limb ischemia mouse model

      We developed an optical coherence tomography angiography technique by improving the speckle contrast algorithm and the imaging process. This technique, which can achieve angiogenesis imaging in vivo without increasing trauma, was used to evaluate the microvasculature in limb ischemia mice. Sixteen left hindlimb ischemia mice were randomly allocated into CuSO 4 and saline groups. Within 7 days after treatment, limb ischemic damage, temperature and histological staining were assessed by traditional methods. In addition, angiogenesis was evaluated using an optical coherence tomography angiography system in vivo . All results were compared. After 7 days of treatment, both the ischemic tissue damage score ...

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    9. Test performance of optical coherence tomography angiography in detecting retinal diseases: a systematic review and meta-analysis

      Test performance of optical coherence tomography angiography in detecting retinal diseases: a systematic review and meta-analysis

      Objective To investigate the diagnostic accuracy of optical coherence tomography angiography (OCTA) in detecting vascular characteristics of chorio-retinal disease. Methods Evidence acquisition: We searched Web of Science, Scopus, and Medline by the citation of references and complemented these electronic searches by checking the list of references of included and review articles. Screening, selection, assessment, and extraction was performed in parallel by two authors. Results Evidence synthesis: Systematic review and exploratory meta-analysis. The ten studies that contributed to the meta-analysis enrolled 440 eyes and allowed constructing ten two-by-two tables. The tables reported on detection of choroidal neovascularization (CNV) in eyes suffering ...

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      Mentions: Pearse A. Keane
    10. Optical coherence tomography angiography of types 1 and 2 choroidal neovascularization in age-related macular degeneration during anti-VEGF therapy: evaluation of a new quantitative method

      Optical coherence tomography angiography of types 1 and 2 choroidal neovascularization in age-related macular degeneration during anti-VEGF therapy: evaluation of a new quantitative method

      Purpose The aim of this pilot study was to test whether mathematical parameters of the vascular morphology of choroidal neovascularization (CNV) can be used as biomarkers and to investigate how these parameters change during anti-vascular endothelial growth factor (VEGF) therapy. Methods Treatment-naive CNV in exudative age-related macular degeneration (AMD) was diagnosed in 28 patients. OCT-angiography (OCT-A) (Avanti/FA Optovue) performed before and after anti-VEGF therapy. The OCT-A data sets were exported to an external image processing program and vessel skeletonization was accomplished by means of edge detection. Based on this technique the total vessel length, the number of segments and ...

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      Mentions: Optovue
    11. Automated drosophila heartbeat counting based on image segmentation technique on optical coherence tomography

      Automated drosophila heartbeat counting based on image segmentation technique on optical coherence tomography

      Drosophila and human cardiac genes are very similar. Biological parametric studies on drosophila cardiac have improved our understanding of human cardiovascular disease. Drosophila cardiac consist of five circular chambers: a conical chamber (CC) and four ostia sections (O1–O4). Due to noise and grayscale discontinuity on optical coherence tomography (OCT) images, previous researches used manual counting or M-mode to analyze heartbeats, which are inefficient and time-consuming. An automated drosophila heartbeat counting algorithm based on the chamber segmentation is developed for OCT in this study. This algorithm has two parts: automated chamber segmentation and heartbeat counting. In addition, this study proposes ...

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    12. Optical coherence tomography evidence of macular ganglion cell-inner plexiform layer thinning in eyes with subretinal drusenoid deposits

      Optical coherence tomography evidence of macular ganglion cell-inner plexiform layer thinning in eyes with subretinal drusenoid deposits

      Background/Objectives The purpose of this study was to evaluate macular ganglion cell layer-inner plexiform layer (GCL-IPL) and choroidal thickness in early age-related macular degeneration (AMD) in eyes with subretinal drusenoid deposits (SDD). Subjects/Methods Comprehensive ophthalmological examination was performed. Near infrared reflectance and raster images using enhanced depth imaging were acquired with spectral domain optical coherence tomography. Drusen and SDD were diagnosed based on raster scans and near infrared reflectance. GCL-IPL maps were generated with automated segmentation and choroidal thickness maps were obtained by manually delineating the choroid-scleral boundary. Results Forty-eight eyes from 48 patients (mean age 77.5 ...

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    13. Foveal and parafoveal choroidal thickness pattern measuring by swept source optical coherence tomography

      Foveal and parafoveal choroidal thickness pattern measuring by swept source optical coherence tomography

      Objective To evaluate the choroidal thickness (CT) in foveal and parafoveal regions in Thai adults using swept-source optical coherence tomography (SS-OCT). Methods We enrolled healthy volunteers ≥18 years of age from King Chulalongkorn Memorial Hospital, Thailand, during September 2015 to March 2016. Optical coherence tomography (OCT) of the macula was performed, and subfoveal CT was measured manually using a line scan. Average thicknesses of retinal and choroidal layers in regions of the Early Treatment Diabetic Retinopathy Study grid were measured automatically. A multivariate analysis was conducted to determine correlations between CTs in the foveal and parafoveal regions and retinal layers ...

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    14. Partially coherent radar unties range resolution from bandwidth limitations

      Partially coherent radar unties range resolution from bandwidth limitations

      It is widely believed that range resolution, the ability to distinguish between two closely situated targets, depends inversely on the bandwidth of the transmitted radar signal. Here we demonstrate a different type of ranging system, which possesses superior range resolution that is almost completely free of bandwidth limitations. By sweeping over the coherence length of the transmitted signal, the partially coherent radar experimentally demonstrates an improvement of over an order of magnitude in resolving targets, compared to standard coherent radars with the same bandwidth. A theoretical framework is developed to show that the resolution could be further improved without a ...

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    15. Automated classification platform for the identification of otitis media using optical coherence tomography

      Automated classification platform for the identification of otitis media using optical coherence tomography

      The diagnosis and treatment of otitis media (OM), a common childhood infection, is a significant burden on the healthcare system. Diagnosis relies on observer experience via otoscopy, although for non-specialists or inexperienced users, accurate diagnosis can be difficult. In past studies, optical coherence tomography (OCT) has been used to quantitatively characterize disease states of OM, although with the involvement of experts to interpret and correlate image-based indicators of infection with clinical information. In this paper, a flexible and comprehensive framework is presented that automatically extracts features from OCT images, classifies data, and presents clinically relevant results in a user-friendly platform ...

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    16. Myopic traction maculopathy biomarkers on optical coherence tomography angiography—An overlooked mechanism of visual acuity correction in myopic eyes

      Myopic traction maculopathy biomarkers on optical coherence tomography angiography—An overlooked mechanism of visual acuity correction in myopic eyes

      Background/objectives Myopic traction maculopathy of the retinoschisis type is a unique entity that has been frequently overlooked in refraction correction in daily practice in myopic eyes. The objective of this study was to describe the imaging characteristics of myopic traction maculopathy (MTM) seen on optical coherence tomography angiography (OCTA) and to detect biomarkers of the associated functional changes. Subjects/methods We performed OCTA on eyes with MTM and retinoschisis (RS group; n  = 27) and highly myopic eyes without MTM (control group; n  = 27). The RS group was further divided into a dome-shaped macula (DSM) group and a non-DSM group ...

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    17. Membrane patterns in eyes with choroidal neovascularization on optical coherence tomography angiography

      Membrane patterns in eyes with choroidal neovascularization on optical coherence tomography angiography

      Background To evaluate morphologic patterns of choroidal neovascular membranes using optical coherence tomography angiography (OCTA) in patients with treatment-naive, continuously treated, and previously treated exudative age-related macular degeneration (AMD). Subjects We assessed retrospectively 184 eyes of 153 patients diagnosed with type 1, type 2, and mixed-type neovascularization associated with AMD. The type of neovascularization and clinical activity were assessed by clinical examination and spectral domain optical coherence tomography (SD-OCT). Morphological patterns of neovascular membranes were categorized using en face images on the AngioVue (Optovue) OCTA system. Results The mean age of patients was 77.9 ± 8.6 years (range, 52 ...

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      Mentions: Optovue
    18. Postdoc in Fabrication of MEMS Tuneable VCSELs

      Postdoc in Fabrication of MEMS Tuneable VCSELs

      The Nanophotonic Devices Group manufactures and characterizes optoelectronic and photonic devices for applications in communication and medical imaging. Fabrication is done in DTU Nanolab where facilities for silicon, GaAs and InP devices are available. Our optical labs are in the new building of DTU Fotonik. The work have enabled a number of high profile results on nanoscale lasers, nonlinear integrated photonics and a spinout company on lasers for optical coherence tomography ( OCT ). Microelectromechanical tuneable vertical cavity surface emitting lasers ( MEMS tuneable VCSELs) have shown remarkable performance for optical coherence tomography where fast wavelength sweep and a large dynamic coherence have ...

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    19. Macular OCT-angiography parameters to predict the clinical stage of nonproliferative diabetic retinopathy: an exploratory analysis

      Macular OCT-angiography parameters to predict the clinical stage of nonproliferative diabetic retinopathy: an exploratory analysis

      Background To test whether a single or a composite set of macular vascular density parameters, evaluated with optical coherence tomography angiography (OCTA), are able to predict nonproliferative diabetic retinopathy (NPDR) staging according to the gold-standard ETDRS-grading scheme. Methods Prospectively defined, cross-sectional study in which macular structural and vascular parameters of diabetic eyes with nonproliferative DR (up to ETDRS Level 53) were evaluated with OCTA (Avanti RTVue-XR 100, Optovue Inc, Fremont, CA). Seven-field photographs of the fundus were taken for DR staging according to the ETDRS-grading scheme. The vessel density in the superficial and deep capillary plexus (SCP and DCP, respectively ...

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    20. Assessment of the anterior segment of patients with primary congenital glaucoma using handheld optical coherence tomography

      Assessment of the anterior segment of patients with primary congenital glaucoma using handheld optical coherence tomography

      Purpose To investigate the potential of handheld optical coherence tomography (HH-OCT) in assessing the anterior segment of the eye in patients with primary congenital glaucoma. Design A prospective, case-controlled observational study. Participants Twenty-two patients with primary congenital glaucoma (PCG, 9 females and 13 males; mean age 4.36 ± 3.4 years) and age-, gender- and ethnicity-matched healthy participants. Methods Anterior OCT was performed in all participants using a high-resolution HH SD-OCT device (Envisu 2300, Leica Microsystems, Germany) without anaesthesia or sedation. Results Anterior HH-OCT in PCG visualised Haab’s striae in 14.3%, uneven internal cornea in 9.5% and ...

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    21. Focus Tracking System for Femtosecond Laser Machining using Low Coherence Interferometry

      Focus Tracking System for Femtosecond Laser Machining using Low Coherence Interferometry

      We designed a real time, single-laser focus tracking system using low coherence properties of the machining femtosecond laser itself in order to monitor and correct the sample position relative to the focal plane. Using a Michelson Interferometer, the system collects data arising from part of the beam backscattered at the ablation spot. The data is analyzed by a custom software for position correction (employing an XYZ automated translation stage). With the focus tracking enabled we were able to etch channels with a stable cross-section profile on a bovine tooth with relief amplitude tens of times greater than the Rayleigh length ...

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      Mentions: Marcus P. Raele
    22. Investigating spontaneous retinal venous pulsation using Doppler optical coherence tomography

      Investigating spontaneous retinal venous pulsation using Doppler optical coherence tomography

      We demonstrate the advantages of optical coherence tomography (OCT) imaging for investigation of spontaneous retinal venous pulsation (SRVP). The pulsatile changes in venous vessel caliber are analyzed qualitatively and quantitatively using conventional intensity-based OCT as well as the functional extension Doppler OCT (DOCT). Single-channel and double-channel line scanning protocols of our multi-channel OCT prototype are employed to investigate venous pulsatile caliber oscillations as well as venous flow pulsatility in the eyes of healthy volunteers. A comparison to recordings of scanning laser ophthalmoscopy (SLO) – a standard en-face imaging modality for evaluation of SRVP – is provided, emphasizing the advantages of tomographic image ...

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    23. Quantitative reconstruction of time-varying 3D cell forces with traction force optical coherence microscopy

      Quantitative reconstruction of time-varying 3D cell forces with traction force optical coherence microscopy

      Cellular traction forces (CTFs) play an integral role in both physiological processes and disease, and are a topic of interest in mechanobiology. Traction force microscopy (TFM) is a family of methods used to quantify CTFs in a variety of settings. State-of-the-art 3D TFM methods typically rely on confocal fluorescence microscopy, which can impose limitations on acquisition speed, volumetric coverage, and temporal sampling or coverage. In this report, we present the first quantitative implementation of a new TFM technique: traction force optical coherence microscopy (TF-OCM). TF-OCM leverages the capabilities of optical coherence microscopy and computational adaptive optics (CAO) to enable the ...

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    24. 3-Dimensional characterization of cortical bone microdamage following placement of orthodontic microimplants using Optical Coherence Tomography

      3-Dimensional characterization of cortical bone microdamage following placement of orthodontic microimplants using Optical Coherence Tomography

      Microimplants are being used extensively in clinical practice to achieve absolute anchorage. Success of microimplant mainly depend on its primary stability onto the cortical bone surface and the associated Microdamage of the cortical bone during insertion procedure leads to many a microimplants to fail and dislodge from the cortical bone leading to its failure. Even though, previous studies showed occurrence of microdamage in the cortical bone, they were mainly 2-dimension studies or studies that were invasive to the host. In the present study, we used a non-invasive, non-ionizing imaging technique- Optical Coherence Tomography (OCT), to image and analyze the presence ...

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    1-24 of 458 1 2 3 4 ... 17 18 19 »
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