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    1. Mid-infrared photonics: Spiral superluminescent emitter

      Mid-infrared photonics: Spiral superluminescent emitter

      Superluminescent (SL) light sources, which offer the beneficial combination of a broad emission bandwidth with low temporal and high spatial coherence, have many potential industrial and medical applications. In particular, mid-infrared (MIR) SL light sources that are suitable for use in an optical coherence tomography system would be attractive for…

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    2. Evaluation of choroidal thickness using enhanced depth imaging by spectral-domain optical coherence tomography in patients with pseudoexfoliation syndrome

      Evaluation of choroidal thickness using enhanced depth imaging by spectral-domain optical coherence tomography in patients with pseudoexfoliation syndrome

      Purpose To investigate the choroidal thickness using optical coherence tomography in the eyes of patients with unilateral and bilateral pseudoexfoliation syndrome and to compare them with healthy controls. Methods We studied four groups: (1) affected eyes from 30 patients with unilateral PEX syndrome affecting the right eye of 17 patients and the left eye of 13 patients; (2) clinically unaffected eyes of 30 patients with unilateral PEX syndrome; (3) the eyes of 30 patients with bilateral PEX syndrome; and (4) the eyes of 30 normal healthy subjects. Choroidal thickness was evaluated using high-speed, high-resolution enhanced depth imaging by spectral-domain optical ...

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    3. Quantitative analysis of retinal layers' optical intensities on 3D optical coherence tomography for central retinal artery occlusion

      Quantitative analysis of retinal layers' optical intensities on 3D optical coherence tomography for central retinal artery occlusion

      Optical coherence tomography (OCT) provides not only morphological information but also information about layer-specific optical intensities, which may represent the underlying tissue properties. The purpose of this study is to quantitatively investigate the optical intensity of each retinal layers in central retinal artery occlusion (CRAO). Twenty-nine CRAO cases at acute phase and 33 normal controls were included. Macula-centered 3D OCT images were segmented with a fully-automated Iowa Reference Algorithm into 10 layers. Layer-specific mean intensities were determined and compared between the patient and control groups using multiple regression analysis while adjusting for age and optical intensity of the entire region ...

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    4. Morphology of human sweat ducts observed by optical coherence tomography and their frequency of resonance in the terahertz frequency region

      Morphology of human sweat ducts observed by optical coherence tomography and their frequency of resonance in the terahertz frequency region

      It is crucial to understand the various biological effects induced by terahertz (THz) electromagnetic waves with the rapid development of electronic and photonic devices operating in the THz frequency region. The presence of sweat glands plays an important role in THz wave interactions with human skin. We investigated the morphological features of sweat ducts using optical coherence tomography (OCT) to further understand such phenomena. We observed remarkable features of the ducts, such as their clear helical structure. The intersubject and intrasubject variations in the diameter of sweat ducts were considerably smaller than the variations in other structural parameters, such as ...

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    5. En face OCT angiography demonstrates flow in early type 3 neovascularization (retinal angiomatous proliferation)

      En face OCT angiography demonstrates flow in early type 3 neovascularization (retinal angiomatous proliferation)

      Introduction The characteristics of type 3 neovascularization (NV), also known as retinal angiomatous proliferation, have been well described clinically, as well as with fluorescein angiography (FA), indocyanine green angiography, and optical coherence tomography (OCT). OCT angiography (OCT-A) is a novel and non-invasive technique for imaging retinal microvasculature by detecting changes, with respect to time, in reflectivity related to blood flow. Method In this case series, we describe two patients who presented with type 3 NV and underwent clinical examination and multimodal imaging, including OCT-A. Results In the first patient, OCT-A demonstrated flow within two separate lesions in the same eye ...

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    6. Correlation of localized glaucomatous visual field defects and spectral domain optical coherence tomography retinal nerve fiber layer thinning using a modified structure-function map for OCT

      Correlation of localized glaucomatous visual field defects and spectral domain optical coherence tomography retinal nerve fiber layer thinning using a modified structure-function map for OCT

      Purpose To study the correlation between glaucomatous visual field (VF) defects assessed by standard automated perimetry (SAP) and peripapillary retinal nerve fiber layer (RNFL) thinning measured by spectral domain optical coherence tomography (OCT) using a modified OCT-based peripapillary RNFL structure–function map. Patients and methods Perimetric glaucoma patients and age-matched normal control subjects were recruited from a university hospital clinic. All eyes underwent testing with the Spectralis spectral domain OCT and SAP on the same day. An OCT-based correspondence map, which correlated VF areas with peripapillary RNFL sectors was created to evaluate the relationship between glaucomatous RNFL thinning and VF ...

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    7. Fluorescein angiography and optical coherence tomography in myopic choroidal neovascularization

      Fluorescein angiography and optical coherence tomography in myopic choroidal neovascularization

      Purpose To assess intra / inter-observer agreement, and diagnostic capabilities of a color fundus photograph, fundus fluorescein angiography (FFA), and spectral domain optical coherence tomography (SD-OCT) in making a diagnosis of myopic choroidal neovascularization (CNV). Patients and methods Two masked observers evaluated FFA and SD-OCT images to identify the presence of myopic CNV in 80 high-myopic eyes of 57 patients. A third masked observer identified CNV on a color fundus photo. Presence of myopic CNV on a fundus photo was defined as presence of subretinal hemorrhage, thickening of the retina and / or visible membrane at the macula. Presence of myopic CNV ...

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    8. Wide-field imaging and OCT vs clinical evaluation of patients referred from diabetic retinopathy screening

      Wide-field imaging and OCT vs clinical evaluation of patients referred from diabetic retinopathy screening

      Purpose Compare wide-field Optomap imaging and optical coherence tomography (OCT) with clinical examination in diabetic retinopathy (DR). Methods Patients referred from Diabetic Eye Screening Programmes to three centres underwent dilated ophthalmoscopy and were assigned a DR grade. Wide-field colour imaging and OCT were then examined by the same clinician at that visit and a combined grade was assigned. Independent graders later reviewed the images and assigned an imaging-only grade. These three grades (clinical, combined, and imaging) were compared. The method that detected the highest grade of retinopathy, including neovascularisation, was determined. Results Two thousand and forty eyes of 1023 patients ...

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    9. Drusen and RPE atrophy automated quantification by optical coherence tomography in an elderly population

      Drusen and RPE atrophy automated quantification by optical coherence tomography in an elderly population

      Purpose Correlate OCT-derived measures of drusen and retinal pigment epithelium (RPE) atrophy areas (RAs) with demographic features in an elderly population. Patients and methods Subjects aged 50 years and older underwent Cirrus OCT scanning. Drusen area and volume were obtained from the macula within a central circle (CC) of 3   mm and a surrounding perifoveal ring (PR) of 3–5   mm, using the RPE analysis software (6.0). RA measurements were generated for the 6 × 6   mm 2 retinal area. Gender, age, smoking status, and systolic blood pressure (SBP) were considered. Results A total of 434 eyes were included. RA ...

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    10. A combined method to quantify the retinal metabolic rate of oxygen using photoacoustic ophthalmoscopy and optical coherence tomography

      A combined method to quantify the retinal metabolic rate of oxygen using photoacoustic ophthalmoscopy and optical coherence tomography

      Quantitatively determining physiological parameters at a microscopic level in the retina furthers the understanding of the molecular pathways of blinding diseases, such as diabetic retinopathy and glaucoma. An essential parameter, which has yet to be quantified noninvasively, is the retinal oxygen metabolic rate (rMRO 2 ). Quantifying rMRO 2 is challenging because two parameters, the blood flow rate and hemoglobin oxygen saturation (sO 2 ), must be measured together. We combined photoacoustic ophthalmoscopy (PAOM) with spectral domain-optical coherence tomography (SD-OCT) to tackle this challenge, in which PAOM measured the sO 2 and SD-OCT mapped the blood flow rate. We tested the integrated ...

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    11. Matching human pathology is essential for validating OCT imaging to detect high-risk plaques

      Matching human pathology is essential for validating OCT imaging to detect high-risk plaques

      We thank Mark Brezinski for his Correspondence ( Capabilities, limitations, and misconceptions of using OCT to assess vulnerable plaques . Nat. Rev. Cardiol. doi:10.1038/nrcardio.2014.62-c1 ) 1 on our Review ( Clinical classification of plaque morphology in coronary disease . Nat. Rev. Cardiol. 11 , 379 – 389 ; 2014 ), 2 and for his comments and clarifications. We agree that the phenomenon

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    12. Evaluation of choroidal thickness using spectral-domain optical coherence tomography in migraine patients during acute migraine attacks: a comparative study

      Evaluation of choroidal thickness using spectral-domain optical coherence tomography in migraine patients during acute migraine attacks: a comparative study

      Purpose The purpose of this study was to assess choroidal thickness in migraine patients during acute migraine attacks and compare them with healthy controls, using spectral domain optical coherence tomography (OCT). Patients and methods In this prospective case–control study, choroidal thicknesses of 46 migraine patients during acute migraine attacks and 46 age- and sex-matched healthy subjects were measured using a high-speed, high-resolution frequency domain-OCT device. All patients underwent a complete ophthalmic examination before the measurements. OCT measurements were taken at the same time of day (0900 hours), in order to minimize the effects of diurnal variation. Results There was ...

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    13. Capabilities, limitations, and misconceptions of using OCT to assess vulnerable plaques

      Capabilities, limitations, and misconceptions of using OCT to assess vulnerable plaques

      Serious concerns exist about the Review by Otsuka et al . (Clinical classification of plaque morphology in coronary disease. Nat. Rev. Cardiol. 11, 379–389; 2014 ), 1 some of which are discussed in this Correspondence. The concerns are predominately about the authors' understanding of the principles and application of optical coherence tomography (OCT),

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    14. Parametric spectro-temporal analyzer (PASTA) for real-time optical spectrum observation

      Parametric spectro-temporal analyzer (PASTA) for real-time optical spectrum observation

      Real-time optical spectrum analysis is an essential tool in observing ultrafast phenomena, such as the dynamic monitoring of spectrum evolution. However, conventional method such as optical spectrum analyzers disperse the spectrum in space and allocate it in time sequence by mechanical rotation of a grating, so are incapable of operating at high speed. A more recent method all-optically stretches the spectrum in time domain, but is limited by the allowable input condition. In view of these constraints, here we present a real-time spectrum analyzer called parametric spectro-temporal analyzer (PASTA), which is based on the time-lens focusing mechanism. It achieves a ...

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    15. Optical coherence tomography for the diagnosis of neovascular age-related macular degeneration: a systematic review

      Optical coherence tomography for the diagnosis of neovascular age-related macular degeneration: a systematic review

      The purpose is to study the diagnostic performance of optical coherence tomography (OCT) and alternative diagnostic tests for neovascular age-related macular degeneration (nAMD). Methods employed are as follows:systematic review and meta-analysis; Index test: OCT including time-domain (TD-OCT) and the most recently developed spectral domain (SD-OCT); comparator tests: visual acuity, clinical evaluation (slit lamp), Amsler chart, colour fundus photographs, infra-red reflectance, red-free images / blue reflectance, fundus autofluorescence imaging (FAF), indocyanine green angiography (ICGA), preferential hyperacuity perimetry (PHP), and microperimetry; reference standard: fundus fluorescein angiography. Databases searched included MEDLINE, MEDLINE In Process, EMBASE, Biosis, SCI, the Cochrane Library, DARE, MEDION, and ...

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    16. Multimodal imaging including spectral-domain optical coherence tomography and confocal near-infrared reflectance for characterization of lacquer cracks in highly myopic eyes

      Multimodal imaging including spectral-domain optical coherence tomography and confocal near-infrared reflectance for characterization of lacquer cracks in highly myopic eyes

      Purpose To compare multimodal imaging in detecting lacquer cracks in highly myopic eyes, and to correlate these findings with those of spectral-domain optical coherence tomography (SD-OCT). Methods An observational case series study. Patients with a refractive error worse than −8 diopters and lacquer cracks were recruited. The rates of detection of the lacquer cracks using multimodal imaging including near-infrared reflectance (NIR) imaging, fundus autofluorescence (FAF) imaging, and fluorescence angiography (FA) were compared. The characteristic findings of multimodal imaging were correlated with those of SD-OCT. Results NIR imaging was more sensitive (92.9 % ) in detecting lacquer cracks than either FAF (12 ...

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    17. Influence of choroidal thickness on subfoveal choroidal thickness measurement repeatability using enhanced depth imaging optical coherence tomography

      Influence of choroidal thickness on subfoveal choroidal thickness measurement repeatability using enhanced depth imaging optical coherence tomography

      Purpose To determine the influence of choroidal thickness (CT) and image setting on repeatability of subfoveal choroidal thickness (SFCT) manual measurement using enhanced depth imaging optical coherence tomography (EDI-OCT). Methods This retrospective study included 189 eyes from 189 adults. Two observers (A and B) measured the SFCT from 1   :   1 micron and 1   :   1 pixel images for evaluation of interobserver repeatability. Observer A performed a single additional measurement for intraobserver repeatability. Results The mean age was 45.1±11.1 years. The mean SFCT from 1   :   1 pixel and 1   :   1 micron images were 315.3±89.2 and 312 ...

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    18. Optical coherence tomography: A new strategy to image planarian regeneration

      Optical coherence tomography: A new strategy to image planarian regeneration

      The planarian is widely used as a model for studying tissue regeneration. In this study, we used optical coherence tomography (OCT) for the real-time, high-resolution imaging of planarian tissue regeneration. Five planaria were sliced transversely to produce 5 head and 5 tail fragments. During a 2-week regeneration period, OCT images of the planaria were acquired to analyze the signal attenuation rates, intensity ratios, and image texture features (including contrast, correlation, homogeneity, energy, and entropy) to compare the primitive and regenerated tissues. In the head and tail fragments, the signal attenuation rates of the regenerated fragments decreased from −0.2 dB ...

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    19. Truncated-correlation photothermal coherence tomography for deep subsurface analysis

      Truncated-correlation photothermal coherence tomography for deep subsurface analysis

      Photothermal diffusion-wave imaging is a promising technique for the analysis of a range of media. However, traditional diffusion-wave techniques are limited by the physics of parabolic diffusion and can only produce depth-integrated planar images. Here, we report a depth-resolved photothermal imaging modality, henceforth termed truncated-correlation photothermal coherence tomography (TC-PCT). This enables three-dimensional visualization of subsurface features, which is not possible with known optical or photothermal imaging techniques. Examples include imaging of solids with intricate subsurface structures and discontinuities, such as holes in steel, burn depth profiles in tissues, and the structure of bone. It is compatible with regulations concerning maximum ...

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    20. Comparison of new motorized injector vs manual injector for implantation of foldable intraocular lenses on wound integrity: an ASOCT study

      Comparison of new motorized injector vs manual injector for implantation of foldable intraocular lenses on wound integrity: an ASOCT study

      Purpose To compare intraocular lens implantation using a motorized injector vs standard manual injector through a 2.2-mm clear corneal incision. Methods Patients underwent standard phacoemulsification using a 2.2-mm clear corneal incision. Hydrophobic acrylic aspheric intraocular lens (Acrysof SN60WF intraocular lens (IOL)) was inserted using D cartridge with manual monarch injector or autosert motorized injector. IOL safety, final incision size and wound integrity in terms of anterior and posterior wound gape, and descemet’s membrane detachment were compared between the two groups at post-operative day 1 and at 1 month using Anterior Segment Optical Coherence Tomography. Results The study ...

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    21. The investigation of acute optic neuritis: a review and proposed protocol

      The investigation of acute optic neuritis: a review and proposed protocol

      Optic neuritis is an inflammatory optic neuropathy that affects many patients with multiple sclerosis (MS) at some point during their disease course. Differentiation of acute episodes of MS-associated optic neuritis from other autoimmune and inflammatory optic neuropathies is vital for treatment choice and further patient management, but is not always straightforward. Over the past decade, a number of new imaging, laboratory and electrophysiological techniques have entered the clinical arena. To date, however, no consensus guidelines have been devised to specify how and when these techniques can be most rationally applied for the diagnostic work-up of patients with acute optic neuritis ...

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    22. 25th RCOphth Congress, President's Session paper: 25 years of progress in medical retina

      25th RCOphth Congress, President's Session paper: 25 years of progress in medical retina

      The quarter century since the foundation of the Royal College of Ophthalmologists has coincided with immense change in the subspecialty of medical retina, which has moved from being the province of a few dedicated enthusiasts to being an integral, core part of ophthalmology in every eye department. In age-related macular degeneration, there has been a move away from targeted, destructive laser therapy, dependent on fluorescein angiography to intravitreal injection therapy of anti-growth factor agents, largely guided by optical coherence tomography. As a result of these changes, ophthalmologists have witnessed a marked improvement in visual outcomes for their patients with wet ...

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    1-24 of 201 1 2 3 4 5 6 7 8 9 »
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