1. 1-24 of 228 1 2 3 4 5 6 7 8 9 10 »
    1. The design and validation of an optical coherence tomography-based classification system for focal vitreomacular traction

      The design and validation of an optical coherence tomography-based classification system for focal vitreomacular traction

      Purpose To develop and validate a classification system for focal vitreomacular traction (VMT) with and without macular hole based on spectral domain optical coherence tomography (SD-OCT), intended to aid in decision-making and prognostication. Methods A panel of retinal specialists convened to develop this system. A literature review followed by discussion on a wide range of cases formed the basis for the proposed classification. Key features on OCT were identified and analysed for their utility in clinical practice. A final classification was devised based on two sequential, independent validation exercises to improve interobserver variability. Results This classification tool pertains to idiopathic ...

      Read Full Article
    2. Is optical coherence tomography an effective device for evaluation of tear film meniscus in patients with acne rosacea?

      Is optical coherence tomography an effective device for evaluation of tear film meniscus in patients with acne rosacea?

      Purpose To investigate the tear meniscus using Fourier-domain optical coherence tomography (FD-OCT) in patients with acne rosacea and to determine the relationship between tear film break-up tests (TBUT), Schirmer test and FD-OCT values and to compare them with that of healthy controls. Methods One hundred and four patients with acne rosacea and 104 body mass index age-sex-matched healthy subjects were enrolled in this prospective case-control study. Tear meniscus height (TMH), tear meniscus depth (TMD), and tear meniscus cross-sectional area (TMA) were measured using FD-OCT (RTVue-100); TBUT, Schirmer test and dry eye questionnaire (OSDI) were evaluated. Correlation was assessed using Spearman ...

      Read Full Article
    3. Persistent subfoveolar fluid following retinal detachment surgery: an SD-OCT guided study on the incidence, aetiological associations, and natural history

      Persistent subfoveolar fluid following retinal detachment surgery: an SD-OCT guided study on the incidence, aetiological associations, and natural history

      Purpose To investigate the incidence and natural history of persistent subfoveolar fluid (PSF) following surgery for macular off rhegmatogenous retinal detachment and the effect of PSF on photoreceptor structure and final visual acuity. Methods Retrospective study of 61 cases with post-operative optical coherence tomography (OCT) performed within 12 weeks of surgery. Based on aetiology, cases were categorized into tractional retinal tears (TRT) group or atrophic round holes and dialyses (RHD) group to investigate the incidence and duration of PSF. A Kaplan–Meier graph was plotted to compare survival time of subfoveolar fluid for both groups. Following secondary reclassification of cases ...

      Read Full Article
    4. Ultrafast optical-ultrasonic system and miniaturized catheter for imaging and characterizing atherosclerotic plaques in vivo

      Ultrafast optical-ultrasonic system and miniaturized catheter for imaging and characterizing atherosclerotic plaques in vivo

      Atherosclerotic coronary artery disease (CAD) is the number one cause of death worldwide. The majority of CAD-induced deaths are due to the rupture of vulnerable plaques. Accurate assessment of plaques is crucial to optimize treatment and prevent death in patients with CAD. Current diagnostic techniques are often limited by either spatial resolution or penetration depth. Several studies have proved that the combined use of optical and ultrasonic imaging techniques increase diagnostic accuracy of vulnerable plaques. Here, we introduce an ultrafast optical-ultrasonic dual-modality imaging system and flexible miniaturized catheter, which enables the translation of this technology into clinical practice. This system ...

      Read Full Article
    5. Intraoperative optical coherence tomography: past, present, and future

      Intraoperative optical coherence tomography: past, present, and future

      To provide an overview of the current state of intraoperative optical coherence tomography (OCT). Literature review of studies pertaining to intraoperative OCT examining both the technology aspects of the imaging platform and the current evidence for patient care. Over the last several years, there have been significant advances in integrative technology for intraoperative OCT. This has resulted in the development of multiple microscope-integrated systems and a rapidly expanding field of image-guided surgical care. Multiple studies have demonstrated the potential role for intraoperative OCT in facilitating surgeon understanding of the surgical environment, tissue configuration, and overall changes to anatomy. In fact ...

      Read Full Article
    6. Intraoperative optical coherence tomography in macula involving rhegmatogenous retinal detachment repair with pars plana vitrectomy and perfluoron

      Intraoperative optical coherence tomography in macula involving rhegmatogenous retinal detachment repair with pars plana vitrectomy and perfluoron

      Purpose To investigate microanatomical relationships during surgical repair of macula involving retinal detachment with pars plana vitrectomy (PPV) and perfluoron (PFO) with a microscope-integrated intraoperative optical coherence tomography (iOCT) device. Patients and methods This consecutive case series included nine eyes of nine patients with macula involving retinal detachment operated by a single surgeon at the Cincinnati Eye Institute. All patients underwent PPV, PFO injection, endolaser, and air–fluid exchange. The macula was imaged with iOCT before PFO injection, after PFO injection, and after air–fluid exchange in all eyes. Results iOCT imaging was ergonomically easy to obtain in all eyes ...

      Read Full Article
    7. 0.54 μm resolution two-photon interference with dispersion cancellation for quantum optical coherence tomography

      0.54 μm resolution two-photon interference with dispersion cancellation for quantum optical coherence tomography

      Quantum information technologies harness the intrinsic nature of quantum theory to beat the limitations of the classical methods for information processing and communication. Recently, the application of quantum features to metrology has attracted much attention. Quantum optical coherence tomography (QOCT), which utilizes two-photon interference between entangled photon pairs, is a promising approach to overcome the problem with optical coherence tomography (OCT): As the resolution of OCT becomes higher, degradation of the resolution due to dispersion within the medium becomes more critical. Here we report on the realization of 0.54  μ m resolution two-photon interference, which surpasses the current record resolution ...

      Read Full Article
    8. Optical coherence tomography-guided laser microsurgery for blood coagulation with continuous-wave laser diode

      Optical coherence tomography-guided laser microsurgery for blood coagulation with continuous-wave laser diode

      Blood coagulation is the clotting and subsequent dissolution of the clot following repair to the damaged tissue. However, inducing blood coagulation is difficult for some patients with homeostasis dysfunction or during surgery. In this study, we proposed a method to develop an integrated system that combines optical coherence tomography (OCT) and laser microsurgery for blood coagulation. Also, an algorithm for positioning of the treatment location from OCT images was developed. With OCT scanning, 2D/3D OCT images and angiography of tissue can be obtained simultaneously, enabling to noninvasively reconstruct the morphological and microvascular structures for real-time monitoring of changes in ...

      Read Full Article
    9. Depth evaluation of intended vs actual intacs intrastromal ring segments using optical coherence tomography

      Depth evaluation of intended vs actual intacs intrastromal ring segments using optical coherence tomography

      Purpose Evaluation of actual vs intended intrastromal corneal ring segments (ICRS) implantation depth as measured by anterior segment optical coherence tomography (OCT) Methods Prospective study evaluating 30 Intacs segments implanted manually in 19 eyes of 15 patients suffering from keratoconus. Segment depth evaluation was performed using anterior segment OCT. Measurements were performed above and below the segment at 3 points in relation to the incision site. Statistical analysis was performed using the SAS software for ANOVA, matched t-test, and GLIMMIX procedure. Results Intacs segment depth was 153-μm shallower than intended (58 % vs 80 % ). Segment layout demonstrated the proximal and ...

      Read Full Article
    10. Retinal vessel structure measurement using spectral-domain optical coherence tomography

      Retinal vessel structure measurement using spectral-domain optical coherence tomography

      Purpose To assess the reliability and validity of spectral-domain optical coherence tomography (SD-OCT) measurements of retinal vessel lumen diameters and wall thicknesses. Methods SD-OCT was used to characterize the circular region around the optic disc of 40 eyes (20 subjects). The inner and outer sides (vitreal and choroidal sides) of the vessel wall and the luminal diameter were measured using intensity graphs. Results Mean arterial and venous luminal diameters were 95.1±16.1 and 132.6±17.8   μm, respectively. The wall thicknesses of inner and outer sides of the artery were 23.9±4.9 and 21.2 ...

      Read Full Article
    11. Visible light optical coherence tomography measures retinal oxygen metabolic response to systemic oxygenation

      Visible light optical coherence tomography measures retinal oxygen metabolic response to systemic oxygenation

      The lack of capability to quantify oxygen metabolism noninvasively impedes both fundamental investigation and clinical diagnosis of a wide spectrum of diseases including all the major blinding diseases such as age-related macular degeneration, diabetic retinopathy, and glaucoma. Using visible light optical coherence tomography (vis-OCT), we demonstrated accurate and robust measurement of retinal oxygen metabolic rate (rMRO 2 ) noninvasively in rat eyes. We continuously monitored the regulatory response of oxygen consumption to a progressive hypoxic challenge. We found that both oxygen delivery, and rMRO 2 increased from the highly regulated retinal circulation (RC) under hypoxia, by 0.28 ± 0.08 µL ...

      Read Full Article
    12. Spectral domain ocular coherence tomography findings pre- and post vitrectomy with fibrovascular membrane delamination for proliferative diabetic retinopathy

      Spectral domain ocular coherence tomography findings pre- and post vitrectomy with fibrovascular membrane delamination for proliferative diabetic retinopathy

      Purpose To describe the intraretinal microstructure using serial spectral domain optical coherence tomography (SD-OCT) preceding and following pars plana vitrectomy and delamination of fibrovascular membranes in patients with proliferative diabetic retinopathy (PDR). Methods This retrospective, interventional case series includes 28 eyes. Outcome measures included LogMAR distance best-corrected visual acuity (BCVA), SD-OCT integrity of photoreceptor inner and outer segments junction (IS / OS), and integrity of external limiting membrane (ELM). Results Pre-operative central macular thickness (CMT) was significantly correlated with the final post-operative LogMAR BCVA (Pearson’s coefficient r = 0.89; P = 0.001). The eyes were categorised into three groups based ...

      Read Full Article
    13. PhD Scholarship in Nano-Imprinting on Chalcogenide MIR-Fiber End-Facets to Reduce Coupling Losses

      PhD Scholarship in Nano-Imprinting on Chalcogenide MIR-Fiber End-Facets to Reduce Coupling Losses

      The strategic research project ShapeOCT will establish a strong Danish research environment in the development and application of ultra-high resolution OCT (optical coherence tomography) imaging equipment for rapid contactless studies of skin cancer in an international collaboration between the Technical University of Denmark, Bispebjerg Hospital and the company NKT Photonics, as well as several strong international partners, such as Harvard Medical School in USA . The system uses as a light source a supercontinuum laser whose enormous spectral bandwidth and high intensity means that an axial resolution of only 2 micron can be achieved. The PhD studentship will be part of ...

      Read Full Article
    14. Laser optomechanics

      Laser optomechanics

      Cavity optomechanics explores the interaction between optical field and mechanical motion. So far, this interaction has relied on the detuning between a passive optical resonator and an external pump laser. Here, we report a new scheme with mutual coupling between a mechanical oscillator supporting the mirror of a laser and the optical field generated by the laser itself. The optically active cavity greatly enhances the light-matter energy transfer. In this work, we use an electrically-pumped vertical-cavity surface-emitting laser (VCSEL) with an ultra-light-weight (130 pg) high-contrast-grating (HCG) mirror, whose reflectivity spectrum is designed to facilitate strong optomechanical coupling, to demonstrate optomechanically-induced ...

      Read Full Article
    15. Peripheral lamina cribrosa depth in primary open-angle glaucoma: a swept-source optical coherence tomography study of lamina cribrosa

      Peripheral lamina cribrosa depth in primary open-angle glaucoma: a swept-source optical coherence tomography study of lamina cribrosa

      Purpose To investigate peripheral lamina cribrosa depth (PLCD) and its vertical-horizontal difference in eyes with primary open-angle glaucoma (POAG). Methods Patients with POAG (n = 90 eyes) and age-matched healthy individuals (n = 90 eyes) underwent swept-source optical coherence tomography (SS-OCT) scans centered at the optic discs. The PLCD was defined as the vertical distance between the most peripheral visible end of anterior lamina cribrosa (LC) surface and the reference plane connecting the Bruch’s membrane openings. The PLCD in each quadrant region and the vertical-horizontal PLCD difference were compared between the POAG and healthy eyes. The clinical factors associated with increased ...

      Read Full Article
    16. Micro-heterogeneity of flow in a mouse model of chronic cerebral hypoperfusion revealed by longitudinal Doppler optical coherence tomography and angiography

      Micro-heterogeneity of flow in a mouse model of chronic cerebral hypoperfusion revealed by longitudinal Doppler optical coherence tomography and angiography

      Although microvascular dysfunction accompanies cognitive decline in aging, vascular dementia, and Alzheimer’s disease, tools to study microvasculature longitudinally in vivo are lacking. Here, we use Doppler optical coherence tomography (OCT) and angiography for noninvasive, longitudinal imaging of mice with chronic cerebral hypoperfusion for up to 1 month. In particular, we optimized the OCT angiography method to selectively image red blood cell (RBC)-perfused capillaries, leading to a novel way of assessing capillary supply heterogeneity in vivo. After bilateral common carotid artery stenosis (BCAS), cortical blood flow measured by Doppler OCT dropped to half of baseline throughout the imaged tissue ...

      Read Full Article
    17. Effect of laser suture lysis on filtration openings: a prospective three-dimensional anterior segment optical coherence tomography study

      Effect of laser suture lysis on filtration openings: a prospective three-dimensional anterior segment optical coherence tomography study

      Purpose To investigate the effects of laser suture lysis (LSL) on filtration openings after trabeculectomy. Methods Prospective study analyzing the changes in the location and width of filtration openings, fluid cavity height, total bleb height, bleb wall thickness, and bleb wall intensity before and after LSL using three-dimensional anterior segment optical coherence tomography (3D AS-OCT). Results Fourteen patients had clear scleral flap image analysis. As five patients underwent LSL twice and two patients underwent LSL thrice, 23 comparison studies were possible. After LSL the intraocular pressure (IOP) decreased (P = 0.0015) from 20.5±5.3 to 14.9±6 ...

      Read Full Article
    18. Prediction of spontaneous closure of traumatic macular hole with spectral domain optical coherence tomography

      Prediction of spontaneous closure of traumatic macular hole with spectral domain optical coherence tomography

      It has been known that some traumatic macular holes can close spontaneously. However, knowledge about the types of macular hole that can close spontaneously is limited. In this retrospective study, we investigated patients with traumatic macular hole who were followed-up for at least 6 months without any surgical intervention. Clinical data and spectral domain optical coherence tomography (SD-OCT) images were compared between groups with and without macular hole closure. Overall, 27 eyes were included. Spontaneous closure of macular hole was observed in 10 (37.0%) eyes. The holes with spontaneous closure had smaller minimum diameter (244.9 ± 114.4 vs ...

      Read Full Article
    19. Spectral-domain optical coherence tomography analysis of persistent subretinal fluid after scleral buckling surgery for macula-off retinal detachment

      Spectral-domain optical coherence tomography analysis of persistent subretinal fluid after scleral buckling surgery for macula-off retinal detachment

      Purpose To determine the predictive value of markers for persistent subretinal fluid (SRF) absorption and the influence of subfoveal fluid on visual outcome after scleral buckle (SB) surgery for rhegmatogenous retinal detachment (RRD). Patients and methods This was a retrospective, observational study. We reviewed the medical records of 64 eyes of 64 patients who underwent SB surgery for macula-off RRD. Patients underwent clinical examination and spectral-domain optical coherence tomography before surgery, at 1 month and every 3 months postoperatively. The height and width of SRF bleb(s) were measured over time. Results Persistent SRF at 1 month was observed in ...

      Read Full Article
    20. Computational high-resolution optical imaging of the living human retina

      Computational high-resolution optical imaging of the living human retina

      High-resolution in vivo imaging is of great importance for the fields of biology and medicine. The introduction of hardware-based adaptive optics (HAO) has pushed the limits of optical imaging, enabling high-resolution near diffraction-limited imaging of previously unresolvable structures 1 , 2 . In ophthalmology, when combined with optical coherence tomography, HAO has enabled a detailed three-dimensional visualization of photoreceptor distributions 3 , 4 and individual nerve fibre bundles 5 in the living human retina. However, the introduction of HAO hardware and supporting software adds considerable complexity and cost to an imaging system, limiting the number of researchers and medical professionals who could benefit ...

      Read Full Article
    21. A novel imaging approach to periocular basal cell carcinoma: in vivo optical coherence tomography and histological correlates

      A novel imaging approach to periocular basal cell carcinoma: in vivo optical coherence tomography and histological correlates

      Purpose Optical coherence tomography (OCT) is a non-invasive imaging method widely used in ophthalmology. Recent developments have produced OCT devices for imaging the skin. The purpose of this study was to investigate Fourier Domain OCT morphological features of periocular basal cell carcinoma (BCC) in correlation with conventional histopathology. Methods Consecutive patients with periocular nodular BCC were prospectively examined with VivoSight OCT (Michelson Ltd) prior to surgical excision. OCT slice mode images were analysed using criteria defined for conventional and HD-OCT; the images were correlated to haematoxylin and eosin stained histology sections. Results A total of 15 patients with periocular BCC ...

      Read Full Article
    22. In vivo quantification of cochlin in glaucomatous DBA/2J mice using optical coherence tomography

      In vivo quantification of cochlin in glaucomatous DBA/2J mice using optical coherence tomography

      The expression of cochlin in the trabecular meshwork (TM) precedes the clinical glaucoma symptoms in DBA/2J mice. The ability to quantify cochlin in the local tissue (TM) offers potential diagnostic and prognostic values. We present two (spectroscopic and magnetomotive) optical coherence tomography (OCT) approaches for in vivo cochlin quantification in a periodic manner. The cochlin-antibody OCT signal remains stable for up to 24 hours as seen at 3.5 hours after injection allowing for repeated quantification in the living mouse eyes.

      Read Full Article
    23. Combined Optical Coherence and Fluorescence Microscopy to assess dynamics and specificity of pancreatic beta-cell tracers

      Combined Optical Coherence and Fluorescence Microscopy to assess dynamics and specificity of pancreatic beta-cell tracers

      The identification of a beta-cell tracer is a major quest in diabetes research. However, since MRI, PET and SPECT cannot resolve individual islets, optical techniques are required to assess the specificity of these tracers. We propose to combine Optical Coherence Microscopy (OCM) with fluorescence detection in a single optical platform to facilitate these initial screening steps from cell culture up to living rodents. OCM can image islets and vascularization without any labeling. Thereby, it alleviates the need of both genetically modified mice to detect islets and injection of external dye to reveal vascularization. We characterized Cy5.5-exendin-3, an agonist of ...

      Read Full Article
    24. OCT angiography and sequential quantitative analysis of type 2 neovascularization after ranibizumab therapy

      OCT angiography and sequential quantitative analysis of type 2 neovascularization after ranibizumab therapy

      Purpose To study the precise structural aspects of a type 2 neovascular membrane in a patient with age-related macular degeneration (AMD) using optical coherence tomography (OCT) angiography and perform sequential quantitative analysis of the membrane after ranibizumab therapy. Patients and methods Split-spectrum amplitude-decorrelation (SSADA) OCT angiography macular cubes (3 × 3   mm) were acquired with a light source centered at 840   nm, a bandwidth of 45   nm, and an A-scan-rate of 70   000 scans per second. Visible pathologic vessels were outlined manually on average intensity projection en face images, and the area of the lesion and the vessel density were measured ...

      Read Full Article
    1-24 of 228 1 2 3 4 5 6 7 8 9 10 »
  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