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    1. Reliability and validity of Cirrus and Spectralis optical coherence tomography for detecting retinal atrophy in Alzheimer’s disease

      Reliability and validity of Cirrus and Spectralis optical coherence tomography for detecting retinal atrophy in Alzheimer’s disease

      Background To evaluate and compare the ability of two Fourier-domain optical coherence tomography (OCT) devices to detect retinal and retinal nerve fibre layer (RNFL) atrophy in patients with Alzheimer’s disease (AD) compared with healthy subjects; to test the intra-session reliability of two OCT devices in AD patients and healthy subjects. Methods AD patients (n = 75) and age-matched healthy subjects (n = 75) underwent three Macular Cube 200 × 200 protocols using the Cirrus and Spectralis OCT devices and three 360° circular scans centred on the optic disc using the Cirrus OCT device, the classic glaucoma application, and the new Nsite Axonal ...

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    2. Association between cystoid spaces on indocyanine green hyperfluorescence and optical coherence tomography after vitrectomy for diabetic macular oedema

      Association between cystoid spaces on indocyanine green hyperfluorescence and optical coherence tomography after vitrectomy for diabetic macular oedema

      Purpose To study retrospectively the characteristics of residual indocyanine green (ICG) fluorescence after ICG-assisted vitrectomy and the association with spectral-domain optical coherence tomography (SD-OCT) findings in diabetic macular oedema (DMO). Methods Thirteen consecutive eyes of 12 patients for whom fundus near-infrared fluorescence and 20° retinal sectional images were obtained using HRA2 and Spectralis OCT, respectively, 5 days after vitrectomy combined with ICG-assisted inner limiting membrane peeling for DMO. The relationship between the characteristics of the ICG hyperfluorescence and the cystoid spaces in the outer plexiform layer (OPL) on SD-OCT images was evaluated. Results A total of 390 well-demarcated areas of ...

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    3. Comparison of spectral domain and swept-source optical coherence tomography in pathological myopia

      Comparison of spectral domain and swept-source optical coherence tomography in pathological myopia

      Purpose To compare optical coherence tomography (OCT) images obtained with swept-source OCT (SS-OCT) and spectral domain OCT (SD-OCT) in pathological myopia. Methods This is a comparative observational cases series. Five patients with pathological myopia underwent SD-OCT and SS-OCT imaging. SS-OCT was performed using a prototype system (Topcon Medical Systems). SD-OCT was performed using enhanced depth imaging on the Heidelberg Spectralis OCT. The closest corresponding scans from the central subfield were compared. Results Eight eyes of five patients with pathological myopia were included (mean spherical equivalent: −16.00±4.70   D). Overall, SS-OCT better visualized retino-choroidal structures. The choroid, inner segment ...

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    4. Retinal and choroidal thickness evaluation by SD-OCT in adults with obstructive sleep apnea-hypopnea syndrome (OSAS)

      Retinal and choroidal thickness evaluation by SD-OCT in adults with obstructive sleep apnea-hypopnea syndrome (OSAS)

      Objective To assess the macular retina and choroidal thickness change in patients with obstructive sleep apnea-hypopnea syndrome (OSAS) with no significant symptoms and pathological changes in the fundus using spectral domain-optical coherence tomography. Methods This prospective, observational case–control study consisted of 53 eyes of 53 patients with OSAS and 12 eyes of 12 age-matched controls. Macular and choroidal thicknesses were measured by optical coherence tomography. Results The foveal and nasal macular thicknesses were significantly different between four groups (P = 0.001, P = 0.016). The foveal thickness of the control group was significantly thinner than that of the severe ...

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    5. Macular thickness measurements with frequency domain-OCT for quantification of axonal loss in chronic papilledema from pseudotumor cerebri syndrome

      Macular thickness measurements with frequency domain-OCT for quantification of axonal loss in chronic papilledema from pseudotumor cerebri syndrome

      Purpose To evaluate the ability of frequency domain-optical coherence tomography (FD-OCT)-measured macular thickness parameters to differentiate between eyes with resolved chronic papilledema and healthy eyes and to evaluate the correlation between FD-OCT measures and visual field (VF) loss on standard automated perimetry (SAP). Methods Fifty-two eyes from 29 patients suffering from pseudotumor cerebri syndrome (PTC) and 62 eyes from 31 normal controls underwent FD-OCT scanning and ophthalmic evaluation including VF with SAP. All patients had previously been submitted to treatment of PTC and had clinically resolved papilledema and stable VF for at least 6 months before the study. Macular ...

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    6. Anterior segment OCT imaging in mucopolysaccharidosestype I, II, and VI

      Anterior segment OCT imaging in mucopolysaccharidosestype I, II, and VI

      Purpose To describe the anterior segment optical coherence tomography (AS-OCT) characteristics of patients with ocular manifestations of mucopolysaccharidoses type I (Hurler), II (Hunter), and VI (Maroteaux–Lamy). Methods Prospective, observational study of nine consecutive patients with variants of mucopolysaccharidosis (MPS) attending the Paediatric Ophthalmology service at Manchester Royal Eye Hospital, UK. All patients underwent Visante AS-OCT imaging as part of their ophthalmic assessment. Results Ocular involvement tended to be symmetrical. Angle-to-angle distance was significantly lower in MPS VI than in MPS I (P = 0.04). Anterior chamber depth, angle opening distance, trabecular-iris space area, and scleral spur angle tended to ...

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    7. Monthly OCT monitoring of Ozurdex for macular oedema related to retinal vascular diseases: re-treatment strategy (OCTOME Report 1)

      Monthly OCT monitoring of Ozurdex for macular oedema related to retinal vascular diseases: re-treatment strategy (OCTOME Report 1)

      Purpose To evaluate the morphological and functional changes following intravitreal Ozurdex (dexamethasone implant) injections in patients with macular oedema (MO) secondary to retinal vascular diseases. Design This is a single centre, exploratory phase III, prospective, open-label clinical study. Methods Thirty patients with MO secondary to retinal vascular disorders underwent assessments for best corrected visual acuity, contrast sensitivity, microperimetry, chromatic sensitivity, macular thickness, and morphology using spectral domain optical coherence tomography (SD-OCT) and fluorescein angiography at baseline. They were treated with intravitreal Ozurdex at baseline and monitored monthly with visual acuity and SD-OCT assessments up to 36 weeks. Re-treatment was permitted ...

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    8. Historic Work: Governments need to strengthen support for scientists who preserve our cultural heritage.

      Historic Work: Governments need to strengthen support for scientists who preserve our cultural heritage.

      In Ireland, parts of England and other areas of Europe there are thousands of artworks that were fashioned from rocks during the Neolithic period and the Bronze Age. Threatened by degradation, such cultural heritage attracts scientists and volunteer citizens to ensure its preservation. The tools that researchers have devised to help in this task are themselves creative. In one project, biogeochemists and geomorphologists have developed non-invasive methods that enable researchers and citizens to monitor and mitigate decay. Scientists interested in protecting historic collections are determining how climate change will affect the rates of chemical degradation of paper and silk, pest ...

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    9. Analyses of shape of eyes and structure of optic nerves in eyes with tilted disc syndrome by swept-source optical coherence tomography and three-dimensional magnetic resonance imaging

      Analyses of shape of eyes and structure of optic nerves in eyes with tilted disc syndrome by swept-source optical coherence tomography and three-dimensional magnetic resonance imaging

      Purpose To evaluate the deeper structures of the optic nerve and to analyze the shape of eyes with tilted disc syndrome (TDS) by swept-source optical coherence tomography (OCT) and three-dimensional magnetic resonance imaging (3D MRI). Methods The medical records of 54 eyes of 36 patients with TDS were reviewed. The patients with TDS and high myopia were analyzed separately from those without high myopia. All the eyes were examined with a swept-source OCT, and 22 of the eyes were examined by 3D MRI. Results A total of 38 eyes of 29 patients were highly myopic and 16 eyes of 15 ...

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    10. Optical coherence tomography findings in spinocerebellar ataxia-3

      Optical coherence tomography findings in spinocerebellar ataxia-3

      Purpose To report optical coherence tomography (OCT) findings in order to detect subclinical alterations of the afferent visual pathways in spinocerebellar ataxia 3 (SCA-3). Patients and methods Nine genetically confirmed patients (18 eyes) were evaluated with a complete ophthalmologic examination including visual acuity, colour vision, visual field test, and retinal nerve fibre layer (RNFL) and macular thickness with OCT Cirrus HD. A neurological examination was performed and the Scale for the Assessment and Rating of Ataxia (SARA score) was determined in all patients. Results The mean RNFL thickness was 77.39 microns, standard deviation (SD) was ±5.93. In 15 ...

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    11. Multiple-capillary measurement of RBC speed, flux, and density with optical coherence tomography

      Multiple-capillary measurement of RBC speed, flux, and density with optical coherence tomography

      As capillaries exhibit heterogeneous and fluctuating dynamics even during baseline, a technique measuring red blood cell (RBC) speed and flux over many capillaries at the same time is needed. Here, we report that optical coherence tomography can capture individual RBC passage simultaneously over many capillaries located at different depths. Further, we demonstrate the ability to quantify RBC speed, flux, and linear density. This technique will provide a means to monitor microvascular flow dynamics over many capillaries at different depths at the same time.

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    12. In vivo Optical Coherence Tomography of Light-Driven Melanosome Translocation in Retinal Pigment Epithelium

      In vivo Optical Coherence Tomography of Light-Driven Melanosome Translocation in Retinal Pigment Epithelium

      Optical coherence tomography (OCT) may revolutionize fundamental investigation and clinical management of age-related macular degeneration and other eye diseases. However, quantitative OCT interpretation is hampered due to uncertain sub-cellular correlates of reflectivity in the retinal pigment epithelium (RPE) and photoreceptor. The purpose of this study was twofold: 1) to test OCT correlates in the RPE, and 2) to demonstrate the feasibility of longitudinal OCT monitoring of sub-cellular RPE dynamics. A high resolution OCT was constructed to achieve dynamic imaging of frog eyes, in which light-driven translocation of RPE melanosomes occurred within the RPE cell body and apical processes. Comparative histological ...

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    13. The comparison of manual vs automated disc margin delineation using spectral-domain optical coherence tomography

      The comparison of manual vs automated disc margin delineation using spectral-domain optical coherence tomography

      Aims To examine the impact of manual vs automated disc margin delineation on optic nerve head (ONH) and retinal nerve fiber layer (RNFL) parameters using spectral-domain optical coherence tomography (SDOCT). Methods A prospective cohort study consisting of normal, glaucoma suspect (GS) and glaucoma patients who underwent ONH and RNFL measurements using SDOCT technology (RTVue; Optovue Inc.). The retinal pigment epithelium / Bruch’s membrane (RPE / BM) complex end points were automatically determined first, and were manually redefined subsequently. Analysis of variance, coefficient of variation (COV), concordance correlation coefficient (CCC), and Bland–Altman plots were used for the analyses. Results Ninety-nine eyes ...

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    14. Picosecond pulses from wavelength-swept continuous-wave Fourier domain mode-locked lasers

      Picosecond pulses from wavelength-swept continuous-wave Fourier domain mode-locked lasers

      Ultrafast lasers have a crucial function in many fields of science; however, up to now, high-energy pulses directly from compact, efficient and low-power semiconductor lasers are not available. Therefore, we introduce a new approach based on temporal compression of the continuous-wave, wavelength-swept output of Fourier domain mode-locked lasers, where a narrowband optical filter is tuned synchronously to the round-trip time of light in a kilometre-long laser cavity. So far, these rapidly swept lasers enabled orders-of-magnitude speed increase in optical coherence tomography. Here we report on the generation of ~60-70 ps pulses at 390 kHz repetition rate. As energy is stored ...

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    15. Optical Coherence Tomography Enabling Non Destructive Metrology of Layered Polymeric GRIN Material

      Optical Coherence Tomography Enabling Non Destructive Metrology of Layered Polymeric GRIN Material

      Gradient Refractive INdex (GRIN) optical components have historically fallen short of theoretical expectations. A recent breakthrough is the manufacturing of nanolayered spherical GRIN (S-GRIN) polymer optical elements, where the construction method yields refractive index gradients that exceed 0.08. Here we report on the application of optical coherence tomography (OCT), including micron-class axial and lateral resolution advances, as effective, innovative methods for performing nondestructive diagnostic metrology on S-GRIN. We show that OCT can be used to visualize and quantify characteristics of the material throughout the manufacturing process. Specifically, internal film structure may be revealed and data are processed to extract ...

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    16. Real-time in vivo computed optical interferometric tomography

      Real-time in vivo computed optical interferometric tomography

      High-resolution real-time tomography of scattering tissues is important for many areas of medicine and biology 1 , 2 , 3 , 4 , 5 , 6 . However, the compromise between transverse resolution and depth-of-field, in addition to low sensitivity deep in tissue, continues to impede progress towards cellular-level volumetric tomography. Computed imaging has the potential to solve these long-standing limitations. Interferometric synthetic aperture microscopy 7 , 8 , 9 is a computed imaging technique enabling high-resolution volumetric tomography with spatially invariant resolution. However, its potential for clinical diagnostics remains largely untapped because full volume reconstructions required lengthy post-processing, and the phase-stability requirements have been difficult to satisfy ...

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    17. Dispersion-cancelled biological imaging with quantum-inspired interferometry

      Dispersion-cancelled biological imaging with quantum-inspired interferometry

      Quantum information science promises transformative impact over a range of key technologies in computing, communication, and sensing. A prominent example uses entangled photons to overcome the resolution-degrading effects of dispersion in the medical-imaging technology, optical coherence tomography. The quantum solution introduces new challenges: inherently low signal and artifacts, additional unwanted signal features. It has recently been shown that entanglement is not a requirement for automatic dispersion cancellation. Such classical techniques could solve the low-signal problem, however they all still suffer from artifacts. Here, we introduce a method of chirped-pulse interferometry based on shaped laser pulses, and use it to produce ...

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    18. Online monitoring of printed electronics by Spectral-Domain Optical Coherence Tomography

      Online monitoring of printed electronics by Spectral-Domain Optical Coherence Tomography

      Spectral-Domain Optical Coherence Tomography (SD-OCT) is an optical method capable of 3D imaging of object's internal structure with micron-scale resolution. Modern SD-OCT tools offer the speed capable of online monitoring of printed devices. This paper demonstrates the use of SD-OCT in a simulated roll-to-roll (R2R) process through monitoring some structural properties of moving screen printed interdigitated electrodes. It is shown that structural properties can be resolved for speeds up to ca. 1 m/min, which is the first step towards application of this method in real manufacturing processes, including roll-to-roll (R2R) printing.

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    19. Effect of a single intravitreal bevacizumab injection on different optical coherence tomographic patterns of diabetic macular oedema

      Effect of a single intravitreal bevacizumab injection on different optical coherence tomographic patterns of diabetic macular oedema

      Purpose The aim of this study is to compare the therapeutic effect of a single intravitreal bevacizumab (IVB) injection in eyes with diabetic macular oedema (DMO) of different patterns determined by optical coherence tomography (OCT). Methods Medical records of patients who had a single IVB injection for DMO were analysed retrospectively. Eyes with a clinically significant DMO and a central foveal thickness (CFT) of 250   μ m or more determined by OCT were included in the analysis. Best-corrected visual acuity (BCVA), CFT and total macular volume values before and after the injection were recorded. Eyes were divided into sponge-like diffuse retinal ...

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    20. Macular thickness changes evaluated with spectral domain optical coherence tomography after uncomplicated phacoemulsification

      Macular thickness changes evaluated with spectral domain optical coherence tomography after uncomplicated phacoemulsification

      Purpose To determine macular thickness changes after uncomplicated cataract surgery using spectral domain optical coherence tomography (OCT). Methods This was a prospective non-randomized, clinical study. Data were analysed for 40 healthy patients undergoing uneventful phacoemulsification. OCT measurements were performed before surgery and postoperatively at day 1, week 1 and 2, and month 1, 2, 3, and 6. The retinal map was divided into central point thickness (CPT), central 1-mm subfield (CSF), and two peripheral ring areas with diameters of 3 and 6   mm. Fellow eyes were used as controls. Retinal thickness change between the operated and fellow eyes were compared ...

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    21. Use of Fourier-domain OCT to detect retinal nerve fiber layer degeneration in Parkinson’s disease patients

      Use of Fourier-domain OCT to detect retinal nerve fiber layer degeneration in Parkinson’s disease patients

      Purpose To demonstrate axonal loss in the retinal nerve fiber layer (RNFL) of patients with Parkinson’s disease (PD) and to evaluate the ability of Fourier-domain optical coherence tomography (OCT) to detect RNFL degeneration and retinal thinning in these patients. Methods PD patients (n = 100) and healthy subjects (n = 100) were included in the study and underwent visual acuity, color vision, and OCT examinations using two next-generation Fourier-domain devices (Spectralis and Cirrus). Differences in the RNFL thicknesses were compared between patients and controls. Results RNFL thicknesses were significantly reduced in PD patients compared with healthy subjects, especially those obtained using ...

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    22. Quantitative imaging of cerebral blood flow velocity and intracellular motility using dynamic light scattering–optical coherence tomography

      Quantitative imaging of cerebral blood flow velocity and intracellular motility using dynamic light scattering–optical coherence tomography

      This paper describes a novel optical method for label-free quantitative imaging of cerebral blood flow (CBF) and intracellular motility (IM) in the rodent cerebral cortex. This method is based on a technique that integrates dynamic light scattering (DLS) and optical coherence tomography (OCT), named DLS–OCT. The technique measures both the axial and transverse velocities of CBF, whereas conventional Doppler OCT measures only the axial one. In addition, the technique produces a three-dimensional map of the diffusion coefficient quantifying nontranslational motions. In the DLS–OCT diffusion map, we observed high-diffusion spots, whose locations highly correspond to neuronal cell bodies and ...

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    1-24 of 170 1 2 3 4 5 6 7 »
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