1. 1-24 of 362 1 2 3 4 ... 13 14 15 »
    1. Comparison of intensity, phase retardation, and local birefringence images for filtering blebs using polarization-sensitive optical coherence tomography

      Comparison of intensity, phase retardation, and local birefringence images for filtering blebs using polarization-sensitive optical coherence tomography

      Polarization-sensitive optical coherence tomography (PS-OCT) allows the recording of depth-resolved polarimetric measurements. It has been reported that phase retardation and local birefringence images can noninvasively detect fibrotic area in blebs after glaucoma surgery. Evaluation of scar fibrosis in blebs is important not only for predicting bleb function, but also for planning revision trabeculectomy. Herein, we characterize the intensity, phase retardation, and local birefringence images of blebs using PS-OCT. A total of 85 blebs from 85 patients who had undergone trabeculectomy were examined. Both phase retardation and local birefringence images detected fibrotic changes in blebs after glaucoma surgery. Phase retardation images ...

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    2. Evaluation of vascular changes with optical coherence tomography angiography after ruthenium-106 brachytherapy of circumscribed choroidal hemangioma

      Evaluation of vascular changes with optical coherence tomography angiography after ruthenium-106 brachytherapy of circumscribed choroidal hemangioma

      Purpose To describe the vascular changes of circumscribed choroidal hemangioma (CCH) after ruthenium-106 brachytherapy using optical coherence tomography angiography (angio-OCT). Methods Seven eyes of 7 patients diagnosed with symptomatic CCH who underwent ruthenium-106 plaque radiotherapy were included in the study. Patients underwent complete ophthalmic examination, bulbar echography and angio-OCT. The same protocol was applied 1 year after ruthenium-106 brachytherapy. Results At baseline, the mean best-corrected visual acuity (BCVA) in affected eyes was 0.67 ± 0.14 logMAR, and the mean tumor thickness was 4.46 ± 0.91 mm measured by standardized A-scan echography. After ruthenium-106 plaque treatment, the mean BCVA ...

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    3. Microperimetry and optical coherence tomography imaging in the fellow eye of patients with unilateral focal ischaemic glaucoma

      Microperimetry and optical coherence tomography imaging in the fellow eye of patients with unilateral focal ischaemic glaucoma

      Purpose To determine whether microperimetry or optical coherence tomography (OCT) imaging can detect early disease in the fellow eye of patients with unilateral focal ischaemic glaucoma. Methods Thirty-seven consecutive adult patients with unilateral focal ischaemic glaucoma with a unilateral split-fixation visual field defect on standard automated perimetry (SAP) with normal SAP in the fellow eye were selected. All patients underwent microperimetry (MAIA, CenterVue, Italy) of the central 10 degrees and OCT imaging (Spectralis, Heidelberg Engineering, Germany) of the retinal nerve fibre layer of both eyes. The main outcome measures were reduced retinal sensitivity on microperimetry and/or retinal nerve fibre ...

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    4. The effect of trabeculectomy surgery on the central visual field in patients with glaucoma using microperimetry and optical coherence tomography

      The effect of trabeculectomy surgery on the central visual field in patients with glaucoma using microperimetry and optical coherence tomography

      Purpose To determine the functional and structural effects of trabeculectomy surgery on patients with advanced glaucoma and central visual field defects in the early post-operative period. Methods Thirty consecutive adult subjects with advanced glaucoma requiring trabeculectomy surgery and an established visual field defect within 10° of fixation underwent microperimetry (MAIA MP-1, CenterVue, Padova, Italy) and optic disc optical coherence tomography (OCT) imaging (Spectralis, Heidelberg Engineering, Germany) pre-operatively, and 1 month and 3 months following trabeculectomy surgery. Main outcome measures were post-trabeculectomy change in mean threshold on microperimetry and nerve fibre layer thickness on OCT. Fellow eyes were used as controls ...

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    5. Near-infrared and mid-infrared semiconductor broadband light emitters

      Near-infrared and mid-infrared semiconductor broadband light emitters

      Semiconductor broadband light emitters have emerged as ideal and vital light sources for a range of biomedical sensing/imaging applications, especially for optical coherence tomography systems. Although near-infrared broadband light emitters have found increasingly wide utilization in these imaging applications, the requirement to simultaneously achieve both a high spectral bandwidth and output power is still challenging for such devices. Owing to the relatively weak amplified spontaneous emission, as a consequence of the very short non-radiative carrier lifetime of the inter-subband transitions in quantum cascade structures, it is even more challenging to obtain desirable mid-infrared broadband light emitters. There have been ...

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    6. Group Leader Position in Ophthalmic Imaging

      Group Leader Position in Ophthalmic Imaging

      The Institute of Molecular and Clinical Ophthalmology Basel ( IOB ) invites applications for a Group Leader position in Ophthalmic Imaging. A competitive start-up, core funding, and access to all core facilities necessary to conduct state-of-the-art biomedical research are provided. We are seeking an outstanding individual who will establish an ambitious research program to develop methods for imaging the human eye, with an emphasis on optical coherence tomography ( OCT ) and two photon laser microscopy. Applications for tenure-track and tenured Group Leader positions are considered. The position will allow to combine research with clinical care in case the applicant is a fully trained ...

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    7. Optical Coherence Tomography Angiography Vessel Density Changes after Acute Intraocular Pressure Elevation

      Optical Coherence Tomography Angiography Vessel Density Changes after Acute Intraocular Pressure Elevation

      To investigate changes in retinal vessel density in optic nerve head (ONH) and macula after acute intraocular pressure (IOP) elevation, we conducted a prospective observational study. Eyes with IOP rise ≥5 mmHg after 2-hour dark room prone provocative test (DRPPT) were included. Vasculature of ONH and macula was examined by optical coherence tomography angiography (OCTA) at baseline and after DRPPT. Among the 65 eyes of 42 individuals, 40 eyes with qualified images were enrolled. Mean IOP rise was 9.6 ± 4.2 mmHg (5.0–23.3 mmHg) after DRPPT. Retinal vessel density did not differ after IOP rise for ...

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    8. Quantitative shadow compensated optical coherence tomography of choroidal vasculature

      Quantitative shadow compensated optical coherence tomography of choroidal vasculature

      Conventionally rendered optical coherence tomography (OCT) images of the posterior segment contain shadows which influence the visualization of deep structures such as the choroid. The purpose of this study was to determine whether OCT shadow compensation (SC) alters the appearance of the choroid and the apparent choroidal vascularity index (CVI), an OCT-derived estimated ratio of luminal to total choroidal volume. All scans were shadow compensated using a previously published algorithm, binarized using a novel validated algorithm and extracted binarized choroid to estimate CVI. On 27 raw swept-source OCT volume-scans of healthy subjects, the effect of SC on CVI was established ...

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      Mentions: K. Bailey Freund
    9. Passively Driven Probe Based on Miniaturized Propeller for Intravascular Optical Coherence Tomography

      Passively Driven Probe Based on Miniaturized Propeller for Intravascular Optical Coherence Tomography

      Optical coherent tomography (OCT) has enabled clinical applications ranging from ophthalmology to cardiology that revolutionized in vivo medical diagnostics in the last few decades, and a variety of endoscopic probes have been developed in order to meet the needs of various endoscopic OCT imaging. We propose a passive driven intravascular optical coherent tomography (IV-OCT) probe in this paper. Instead of using any electrically driven scanning device, the probe makes use of the kinetic energy of the fluid that flushes away the blood during the intravascular optical coherence tomography imaging. The probe converts it into the rotational kinetic energy of the ...

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    10. Association between optical coherence tomography based retinal microvasculature characteristics and myocardial infarction in young men

      Association between optical coherence tomography based retinal microvasculature characteristics and myocardial infarction in young men

      Incident myocardial infarction (MI) is a leading cause of adult mortality in the United States. However, because MI has a relatively low incidence in the young population, little information exists on the disease in younger adults. Because the retina has the unique quality that its vasculature is readily and noninvasively visible, the retina is frequently studied to evaluate correlations between vessels and cardiovascular diseases. In the current study, we evaluated the retinal microvasculature of patients who had experienced an MI before 50 years of age (n = 53 subjects) and age- and sex-matched patients who had not experienced an MI (n ...

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    11. Diagnostic capacity of SD-OCT segmented ganglion cell complex versus retinal nerve fiber layer analysis for congenital glaucoma

      Diagnostic capacity of SD-OCT segmented ganglion cell complex versus retinal nerve fiber layer analysis for congenital glaucoma

      Purpose To compare the diagnostic performance of circumpapillary retinal nerve fiber layer (cpRNFL) analysis versus segmented ganglion cell complex analysis both by spectral-domain optical coherence tomography (SD-OCT) in children with primary congenital glaucoma (PCG). Methods Participants were 40 children diagnosed with PCG and 60 healthy children. Ophthalmological data collected (for one eye per child) were cup-disc ratio (C/D) and axial length (AL). SD-OCT with automated segmentation was used to measure the thicknesses and volumes of the macular retinal nerve fiber layer (mRNFL), ganglion cell layer (GCL), and inner plexiform layer (IPL). For the cpRNFL measurements conventional S-D OCT software ...

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    12. The use of optical coherence tomography angiography for detecting choroidal neovascularization, compared to standard multimodal imaging

      The use of optical coherence tomography angiography for detecting choroidal neovascularization, compared to standard multimodal imaging

      Purpose To assess OCT angiography (OCTA) effectiveness at detecting choroidal neovascularization (CNV) in cases of suspected neovascular age related macular degeneration (nAMD), chronic central serous retinopathy (cCSR) and pathological myopia compared to FFA and how it compares to a multimodal approach (OCT, FFA and ICGA) for detecting the vascular network. Methods This was a retrospective observational cohort study of patients who had clinical and/or OCT findings suggestive of CNV, having further investigation with FFA, with or without ICG, and had same day OCTA using the Heidelberg Spectralis OCT2 beta angiography module. Multimodal imaging interpretation was compared to OCTA images ...

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    13. Macular assessment of preoperative optical coherence tomography in ageing Chinese undergoing routine cataract surgery

      Macular assessment of preoperative optical coherence tomography in ageing Chinese undergoing routine cataract surgery

      This retrospective consecutive case series aimed to evaluate spectral-domain optical coherence tomography (SD-OCT) for occult macular disease recognition preoperatively in patients scheduled for routine cataract surgery. All patients scheduled for cataract surgery underwent macular SD-OCT. Scans were reviewed for retinal, retinal pigment epithelium and vitreomacular interface abnormalities. For the subgroup analysis, the following information was collected: age; sex; and diabetes, hypertension, myopia, glaucoma, post intra-ocular surgery, endophotocoagulation, retinal vasculopathy and uveitis statuses. One-thousand-one-hundred-seventy-six consecutive scans were acquired from 1,176 patients. Macular pathology was found in 294 eyes. The most common macular disorders were an epiretinal membrane (n = 130), myopia ...

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    14. Visualization of neuritic plaques in Alzheimer’s disease by polarization-sensitive optical coherence microscopy

      Visualization of neuritic plaques in Alzheimer’s disease by polarization-sensitive optical coherence microscopy

      One major hallmark of Alzheimer’s disease (AD) and cerebral amyloid angiopathy (CAA) is the deposition of extracellular senile plaques and vessel wall deposits composed of amyloid-beta (A β ). In AD, degeneration of neurons is preceded by the formation of A β plaques, which show different morphological forms. Most of them are birefringent owing to the parallel arrangement of amyloid fibrils. Here, we present polarization sensitive optical coherence microscopy (PS-OCM) for imaging mature neuritic A β plaques based on their birefringent properties. Formalin-fixed, post-mortem brain samples of advanced stage AD patients were investigated. In several cortical brain regions, neuritic A β plaques were successfully ...

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    15. Ocular fundus pulsations within the posterior rat eye: Chorioscleral motion and response to elevated intraocular pressure

      Ocular fundus pulsations within the posterior rat eye: Chorioscleral motion and response to elevated intraocular pressure

      A multi-functional optical coherence tomography (OCT) approach is presented to determine ocular fundus pulsations as an axial displacement between the retina and the chorioscleral complex in the albino rat eye. By combining optical coherence elastography and OCT angiography (OCTA), we measure subtle deformations in the nanometer range within the eye and simultaneously map retinal and choroidal perfusion. The conventional OCT reflectivity contrast serves as a backbone to segment the retina and to define several slabs which are subsequently used for quantitative ocular pulsation measurements as well as for a qualitative exploration of the multi-functional OCT image data. The proposed concept ...

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    16. Ugly ducklings—the dark side of plastic materials in contact with potable water

      Ugly ducklings—the dark side of plastic materials in contact with potable water

      Bath toys pose an interesting link between flexible plastic materials, potable water, external microbial and nutrient contamination, and potentially vulnerable end-users. Here, we characterized biofilm communities inside 19 bath toys used under real conditions. In addition, some determinants for biofilm formation were assessed, using six identical bath toys under controlled conditions with either clean water prior to bathing or dirty water after bathing. All examined bath toys revealed notable biofilms on their inner surface, with average total bacterial numbers of 5.5 × 10 6  cells/cm 2 (clean water controls), 9.5 × 10 6  cells/cm 2 (real bath toys ...

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    17. Space flight-associated neuro-ocular syndrome (SANS)

      Space flight-associated neuro-ocular syndrome (SANS)

      Interesting novel and somewhat perplexing physiologic and pathologic neuro-ocular findings have been documented in astronauts during and after long duration space flight (LDSF). These findings collectively have been termed the “space flight-associated neuro-ocular syndrome” (SANS). The National Aeronautics and Space Administration (NASA) in the United States has meticulously and prospectively documented the clinical, ultrasound, optical coherence tomography imaging, and radiographic findings of SANS including unilateral and bilateral optic disc edema, globe flattening, choroidal and retinal folds, hyperopic refractive error shifts, and nerve fiber layer infarcts (i.e., cotton wool spots). NASA and collaborating researchers continue to study SANS in preparation ...

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    18. Changes in optical coherence tomography measurements after orbital wall decompression in dysthyroid optic neuropathy

      Changes in optical coherence tomography measurements after orbital wall decompression in dysthyroid optic neuropathy

      Purpose The purpose of our study was to assess changes in peripapillary retinal nerve fiber layer (RNFL) thickness after orbital wall decompression in eyes with dysthyroid optic neuropathy (DON). Methods We analyzed peripapillary optical coherence tomography (OCT) images (Cirrus HD-OCT) from controls and patients with DON before and 1 and 6 months after orbital wall decompression. Results There was no significant difference in mean preoperative peripapillary retinal nerve fiber layer thickness between eyes with DON and controls. The superior and inferior peripapillary RNFL thickness decreased significantly 1 month after decompression surgery compared to preoperative values ( p  = 0.043 and p ...

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    19. Postdoctoral Fellow, In Vivo Ophthalmology at Roche in Basel, Switzerland

      Postdoctoral Fellow, In Vivo Ophthalmology at Roche in Basel, Switzerland

      We are seeking an exceptional, highly motivated, and talented postdoctoral fellow ( DVM , PhD, or MD-PhD) to perform in vivo and ex vivo experiments to explore safety of novel therapeutic targets for ocular diseases. In this position you will interact closely with other scientists and technicians in a laboratory. Specifically, you will: · Perform ocular examinations of animal models in drug safety studies; · Apply established in vivo imaging modalities, including optical coherence tomography ( OCT ) in conjunction with further diagnostic techniques such as electroretinography ( ERG ); · Participate in ongoing research projects ; · Train and supervise laboratory technicians and fellow researchers to expand skills and knowledge ...

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    20. Unmeasurable small size of foveal avascular zone without visual impairment in optical coherence tomography angiography

      Unmeasurable small size of foveal avascular zone without visual impairment in optical coherence tomography angiography

      Purpose To report the clinical characteristics of eyes with an unmeasurable small size of foveal avascular zone (FAZ) in the optical coherence tomography angiographic (OCTA) images. Methods Two-hundred sixty-seven eyes of 255 patients (mean age 60.4 years) without retinal and choroidal disorders to cause any type of visual impairment were examined by optical coherence tomography angiography (OCTA; RTVue XR Avanti, Optovue, Fremont, CA). Cross-sectional images at the fovea (DRI-OCT, Topcon, Japan) and fundus autofluorescence (CX-1 MYD/NM, Canon, Japan) were also recorded from all eyes. Results Four eyes (1.5%) of 3 patients (2 men, 1 woman; average age ...

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    21. Clinical Translation of Tethered Confocal Microscopy Capsule for Unsedated Diagnosis of Eosinophilic Esophagitis

      Clinical Translation of Tethered Confocal Microscopy Capsule for Unsedated Diagnosis of Eosinophilic Esophagitis

      Esophagogastroduodenoscopy (EGD) is a widely used procedure, posing significant financial burden on both healthcare systems and patients. Moreover, EGD is time consuming, sometimes difficult to tolerate, and suffers from an imperfect diagnostic yield as the limited number of collected biopsies does not represent the whole organ. In this paper, we report on technological and clinical feasibility of a swallowable tethered endomicroscopy capsule, which is administered without sedation, to image large regions of esophageal and gastric mucosa at the cellular level. To demonstrate imaging capabilities, we conducted a human pilot study (n = 17) on Eosinophilic Esophagitis (EoE) patients and healthy volunteers ...

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    22. Unmeasurable small size of foveal avascular zone without visual impairment in optical coherence tomography angiography

      Unmeasurable small size of foveal avascular zone without visual impairment in optical coherence tomography angiography

      Purpose To report the clinical characteristics of eyes with an unmeasurable small size of foveal avascular zone (FAZ) in the optical coherence tomography angiographic (OCTA) images. Methods Two-hundred sixty-seven eyes of 255 patients (mean age 60.4 years) without retinal and choroidal disorders to cause any type of visual impairment were examined by optical coherence tomography angiography (OCTA; RTVue XR Avanti, Optovue, Fremont, CA). Cross-sectional images at the fovea (DRI-OCT, Topcon, Japan) and fundus autofluorescence (CX-1 MYD/NM, Canon, Japan) were also recorded from all eyes. Results Four eyes (1.5%) of 3 patients (2 men, 1 woman; average age ...

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    23. Optophysiological Characterisation of Inner Retina Responses with High-Resolution Optical Coherence Tomography

      Optophysiological Characterisation of Inner Retina Responses with High-Resolution Optical Coherence Tomography

      Low coherence laser interferometry has revolutionised quantitative biomedical imaging of optically transparent structures at cellular resolutions. We report the first optical recording of neuronal excitation at cellular resolution in the inner retina by quantifying optically recorded stimulus-evoked responses from the retinal ganglion cell layer and comparing them with an electrophysiological standard. We imaged anaesthetised paralysed tree shrews, gated image acquisition, and used numerical filters to eliminate noise arising from retinal movements during respiratory and cardiac cycles. We observed increases in contrast variability in the retinal ganglion cell layer and nerve fibre layer with flash stimuli and gratings. Regions of interest ...

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