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    1. Diagnostic accuracy of OCTA and OCT for myopic choroidal neovascularisation: a systematic review and meta-analysis

      Diagnostic accuracy of OCTA and OCT for myopic choroidal neovascularisation: a systematic review and meta-analysis

      Background/objectives: The purpose of this project was to systematically review and meta-analyse studies assessing the diagnostic accuracy of optical coherence tomography angiography (OCTA) and optical coherence tomography (OCT) for myopic choroidal neovascularisation (mCNV). Fluorescein angiography (FA) was accepted as the reference standard. Methods: PUBMED and EMBASE were searched from inception to March 2021 for studies evaluating the test accuracy of OCTA and/or OCT for diagnosing mCNV. The Preferred Reporting Items for Systematic Reviews and Meta-analyses of Diagnostic Test Accuracy Studies guideline was followed, and the Grading of Recommendations, Assessment, Development and Evaluation approach was used to frame clinical ...

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    2. Organ of Corti vibrations are dominated by longitudinal motion in vivo

      Organ of Corti vibrations are dominated by longitudinal motion in vivo

      Recent observations of sound-evoked vibrations of the cochlea’s sensory organ of Corti (ooC) using optical coherence tomography (OCT) have revealed unanticipated and complex motions. Interpreting these results in terms of the micromechanical inner-ear processes that precede hair-cell transduction is not trivial since OCT only measures a projection of the true motion, which may include transverse and longitudinal displacements. We measure ooC motions at multiple OCT beam angles relative to the longitudinal axis of the basilar membrane (BM) by using the cochlea’s natural curvature and find that the relative phase between outer hair cells (OHC) and BM varies with ...

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    3. High speed photo-mediated ultrasound therapy integrated with OCTA

      High speed photo-mediated ultrasound therapy integrated with OCTA

      Photo-mediated Ultrasound Therapy (PUT), as a new anti-vascular technique, can promote cavitation activity to selectively destruct blood vessels with a significantly lower amount of energy when compared to energy level required by other laser and ultrasound treatment therapies individually. Here, we report the development of a high speed PUT system based on a 50-kHz pulsed laser to achieve faster treatment, decreasing the treatment time by a factor of 20. Furthermore, we integrated it with optical coherence tomography angiography (OCTA) for real time monitoring. The feasibility of the proposed OCTA-guided PUT was validated through in vivo rabbit experiments. The addition of ...

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    4. Anterior segment optical coherence tomography characteristics of conjunctival papilloma as compared to papilliform ocular surface squamous neoplasia

      Anterior segment optical coherence tomography characteristics of conjunctival papilloma as compared to papilliform ocular surface squamous neoplasia

      Purpose To describe the anterior segment optical coherence tomography (AS-OCT) appearance of conjunctival papilloma and identify differentiating features from papilliform ocular surface squamous neoplasia (OSSN). Method A retrospective chart review of individuals clinically diagnosed with conjunctival papilloma ( n  = 10) or papilliform OSSN ( n  = 10) based on slit lamp features. Data on demographics, tumour characteristics, and primary treatment were collected. AS-OCT features were assessed including epithelial thickness and reflectivity, a corrugated epithelial surface, presence of an overhanging edge, presence of intrinsic spaces and posterior shadowing. Histopathology was available in 5 papilloma and 3 OSSN specimens. Result Overall, the majority of individuals ...

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    5. Birefringence-derived scleral artifacts in optical coherence tomography images of eyes with pathologic myopia

      Birefringence-derived scleral artifacts in optical coherence tomography images of eyes with pathologic myopia

      We investigated birefringence-derived scleral artifacts in optical coherence tomography (OCT) images of eyes with pathologic myopia. This study included 76 eyes of 42 patients with pathologic myopia. Five sets of OCT B-scan images of the macula were obtained using commercial swept-source OCT. A dataset of prototype swept-source polarization-diversity OCT images was used to identify polarization-dependent OCT images (i.e., complex averaging of OCT signals from two polarization channels) and polarization-independent OCT images (i.e., intensity averaging of two OCT signals). Polarization-dependent OCT images and commercial OCT images were assessed for the presence of birefringence-derived artifacts by comparison with polarization-independent OCT ...

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    6. On-field optical imaging data for the pre-identification and estimation of leaf deformities

      On-field optical imaging data for the pre-identification and estimation of leaf deformities

      Visually nonidentifiable pathological symptoms at an early stage are a major limitation in agricultural plantations. Thickness reduction in palisade parenchyma (PP) and spongy parenchyma (SP) layers is one of the most common symptoms that occur at the early stage of leaf diseases, particularly in apple and persimmon. To visualize variations in PP and SP thickness, we used optical coherence tomography (OCT)-based imaging and analyzed the acquired datasets to determine the threshold parameters for pre-identifying and estimating persimmon and apple leaf abnormalities using an intensity-based depth profiling algorithm. The algorithm identified morphological differences between healthy, apparently-healthy, and infected leaves by ...

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    7. An optically-guided cochlear implant sheath for real-time monitoring of electrode insertion into the human cochlea

      An optically-guided cochlear implant sheath for real-time monitoring of electrode insertion into the human cochlea

      In cochlear implant surgery, insertion of perimodiolar electrode arrays into the scala tympani can be complicated by trauma or even accidental translocation of the electrode array within the cochlea. In patients with partial hearing loss, cochlear trauma can not only negatively affect implant performance, but also reduce residual hearing function. These events have been related to suboptimal positioning of the cochlear implant electrode array with respect to critical cochlear walls of the scala tympani (modiolar wall, osseous spiral lamina and basilar membrane). Currently, the position of the electrode array in relation to these walls cannot be assessed during the insertion ...

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    8. Co-axial acoustic-based optical coherence vibrometry probe for the quantification of resonance frequency modes in ocular tissue

      Co-axial acoustic-based optical coherence vibrometry probe for the quantification of resonance frequency modes in ocular tissue

      We present a co-axial acoustic-based optical coherence vibrometry probe (CoA-OCV) for vibro-acoustic resonance quantification in biological tissues. Sample vibrations were stimulated via a loudspeaker, and pre-compensation was used to calibrate the acoustic spectrum. Sample vibrations were measured via phase-sensitive swept-source optical coherence tomography (OCT). Resonance frequencies of corneal phantoms were measured at varying intraocular pressures (IOP), and dependencies on Young´s Modulus (E), phantom thickness and IOP were observed. Cycling IOP revealed hysteresis. For E = 0.3 MPa, resonance frequencies increased with IOP at a rate of 3.9, 3.7 and 3.5 Hz/mmHg for varied thicknesses and ...

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    9. Cochlear motion across the reticular lamina implies that it is not a stiff plate

      Cochlear motion across the reticular lamina implies that it is not a stiff plate

      Within the cochlea, the basilar membrane (BM) is coupled to the reticular lamina (RL) through three rows of piezo-like outer hair cells (OHCs) and supporting cells that endow mammals with sensitive hearing. Anatomical differences across OHC rows suggest differences in their motion. Using optical coherence tomography, we measured in vivo and postmortem displacements through the gerbil round-window membrane from approximately the 40–47 kHz best-frequency (BF) regions. Our high spatial resolution allowed measurements across the RL surface at the tops of the three rows of individual OHCs and their bottoms, and across the BM. RL motion varied radially; the third-row ...

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    10. Quantitative analysis of choroidal vasculature in central serous chorioretinopathy using ultra-widefield swept-source optical coherence tomography angiography

      Quantitative analysis of choroidal vasculature in central serous chorioretinopathy using ultra-widefield swept-source optical coherence tomography angiography

      We aimed to quantitatively compare the choroid blood flow and choroid thickness at the periphery among eyes with central serous chorioretinopathy (CSC), fellow eyes and healthy eyes using ultra-widefield swept-source optical coherence tomography angiography (UWF SS-OCTA). Retrospective analysis of 49 patients with CSC (98 eyes, including unaffected fellow eyes) and 49 age and sex matched controls were included. We obtained 3-dimensional data of vertical 20 mm × horizontal 24 mm × scan depth 6 mm, comprising 9 subfields (superotemporal, upper, superonasal, temporal, central, nasal, inferotemporal, lower, inferonasal regions). CSC eyes presented with greater density of large-vessel choroidal layer in all the 9 ...

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    11. Prediction of textile pilling resistance using optical coherence tomography

      Prediction of textile pilling resistance using optical coherence tomography

      This paper describes a new method of textile pilling prediction, based on multivariate analysis of the spatial layer above the surface. The original idea of the method is the acquisition of 3D fabric image using optical coherence tomography (OCT) with infrared light, which allows for the fabric fuzz visualization with high sensitivity. The pilling layer, reconstructed with the resolution of 10 × 10 × 5.5 μ m 10×10×5.5μm , includes reliable textural information related to the amount of loose fibers and bunches appearing as a result of abrasion. Pilling intensity was assigned by supervised classification of the textural features ...

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    12. The effect of postmenopausal hormonal drop on optic nerve head and peripapillary perfusion using optical coherence tomography angiography (OCTA)

      The effect of postmenopausal hormonal drop on optic nerve head and peripapillary perfusion using optical coherence tomography angiography (OCTA)

      We studied the effect of menopause with subsequent estrogen drop on optic nerve head structure and peripapillary vasculature. This cross-sectional analytic study was carried out on 100 eyes of 100 patients; patients were divided into a premenopausal group (50 eyes) and a postmenopausal group (50 eyes). Optical coherence tomography was done to evaluate retinal nerve fiber layer thickness (RNFLT) and optical coherence tomography angiography (OCTA) to assess the peripapillary capillary vessel density. RNFLT as well as the peripapillary vessel density (VD) were significantly lower in the postmenopausal group (P value < 0.001) with increasing age, hormonal drop, and higher intraocular ...

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    13. Regular and irregular astigmatism of bullous keratopathy using Fourier harmonic analysis with anterior segment optical coherence tomography

      Regular and irregular astigmatism of bullous keratopathy using Fourier harmonic analysis with anterior segment optical coherence tomography

      Bullous keratopathy (BK) is known to present with corneal edema and Descemet's folds, which can cause corneal astigmatism. However, no report quantitatively evaluated BK astigmatism by separating it into regular and irregular astigmatism. This study investigated the regular and irregular astigmatism of the anterior and posterior corneal surface with Fourier harmonic analysis and anterior segment optical coherence tomography. Preoperative data from 43 eyes of 41 BK patients who received corneal endothelial transplantation were compared with the data from 43 eyes of 43 subjects without corneal disease. Anterior and posterior cylinder power, central corneal thickness (CCT) and thinnest corneal thickness ...

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    14. Evaluation of choroidal thickness with OCT in COVID-19 patients with high D-dimer levels

      Evaluation of choroidal thickness with OCT in COVID-19 patients with high D-dimer levels

      To evaluate retinal and choroidal thickness with optical coherence tomography (OCT) to detect retinal and choroidal pathologies in coronavirus disease 2019 (COVID-19) patients with high D-dimer levels. Thirty patients who were hospitalized in the intensive care unit due to severe acute respiratory syndrome coronavirus 2 and whose D-dimer levels were high during this period, who applied to the internal medicine outpatient clinic between 15 and 30 days after discharge, and 30 healthy volunteers with similar age and gender as the control group was included in the study. After full ophthalmological examination, central foveal and choroidal thicknesses were evaluated using optical ...

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    15. Effect of Weiss ring on peripapillary retinal nerve fiber layer thickness measurements using SD-OCT

      Effect of Weiss ring on peripapillary retinal nerve fiber layer thickness measurements using SD-OCT

      Spectral-domain optical coherence tomography (SD-OCT) must accurately identify and measure the peripapillary retinal nerve fiber layer (pRNFL) thickness to improve the repeatability and reproducibility, and reduce measurement errors. Because Weiss ring can be located in front of the optic disc, we hypothesized that it may affect pRNFL thickness measurements obtained using SD-OCT. We retrospectively reviewed the medical records of patients with (group W) and without (group N) Weiss ring, observed on OCT fundus image and an RNFL map devised using SD-OCT. Optic disc cube scans (200 × 200) were obtained to measure pRNFL thicknesses (superior, temporal, inferior, nasal, and average) at ...

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    16. Changes in the deep vasculature assessed using anterior segment OCT angiography following trabecular meshwork targeted minimally invasive glaucoma surgery

      Changes in the deep vasculature assessed using anterior segment OCT angiography following trabecular meshwork targeted minimally invasive glaucoma surgery

      The effect of trabecular meshwork (TM)-targeted minimally invasive glaucoma surgery (MIGS) on the vasculature assessed using anterior segment (AS)-optical coherence tomography angiography (OCTA) has not been established. In this prospective, longitudinal study, we investigated changes in the deep vasculature following TM-targeted MIGS using AS-OCTA for open-angle glaucoma in 31 patients. AS-OCTA images of the sclera and conjunctiva at the nasal corneal limbus were acquired preoperatively and 3 months postoperatively, and the vessel densities (VDs) of the superficial (conjunctival) and deep (intrascleral) layers were calculated. The VDs before and after MIGS were compared, and the factors associated with the ...

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    17. Stabilization of macular, peripapillary and papillary vascular parameters after XEN and trabeculectomy visualized by the optical coherence tomography angiography

      Stabilization of macular, peripapillary and papillary vascular parameters after XEN and trabeculectomy visualized by the optical coherence tomography angiography

      To analyze the effect of filtration in glaucoma surgery, XEN versus trabeculectomy, on the vessel area density (VAD) of the macular, papillary and peripapillary regions using optical coherence tomography angiography (OCT-A). This prospective cohort study analyzes the vascular architecture of 47 eyes of 45 patients after two different filtrating surgery procedures (XEN stent and trabeculectomy (TE)) using the OCT-A. Participants who had an outsourced medical anti-glaucoma therapy received filtrating surgery in a 2:1 (XEN: TE) ratio. The primary outcome measurements were changes in the VAD in various layers of retinal perfusion and the foveal avascular zone (FAZ). Both interventions ...

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    18. Retinal vascular assessment in psoriatic patients with and without metabolic syndrome using optical coherence tomography angiography

      Retinal vascular assessment in psoriatic patients with and without metabolic syndrome using optical coherence tomography angiography

      To evaluate the retinal vasculature in psoriasis patients and detect if metabolic syndrome is an additional risk factor. This cross-sectional analytic study was carried out on 80 eyes of 80 subjects; 28 eyes with psoriasis only (PS group), 12 eyes with additional metabolic syndrome to psoriasis (PMS group) and 40 eyes healthy controls (HS). The retinal capillary plexuses were evaluated by OCTA. The disease activity was evaluated by the Psoriasis Area and Severity Index (PASI) score and extent. The superficial capillary plexus (SCP) vascular density was significantly lower in PS group than HS while in PMS it was significantly lower ...

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    19. Influence of scan direction on subfoveal choroidal vascularity index using optical coherence tomography

      Influence of scan direction on subfoveal choroidal vascularity index using optical coherence tomography

      We investigated the influence of scan direction on subfoveal choroidal vascularity index (CVI) measurements using spectral-domain optical coherence tomography (SD-OCT) in young healthy subjects. Seventy-eight eyes of 41 healthy volunteers were included. Choroidal structures were obtained using SD-OCT with enhanced depth imaging (EDI) through radial scans at the center of the macula. The subfoveal choroidal images in the horizontal (0°), 45°, vertical (90°) and - 45° directions were recorded and CVIs were analyzed according to their respective directions using image binarization. Additionally, subfoveal choroidal thickness (SFCT), and axial eye length were measured. The SFCT and subfoveal CVI showed a negative correlation ...

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    20. Optical coherence tomography findings after surgery for sub-inner limiting membrane hemorrhage due to ruptured retinal arterial macroaneurysm

      Optical coherence tomography findings after surgery for sub-inner limiting membrane hemorrhage due to ruptured retinal arterial macroaneurysm

      Ruptured retinal arterial macroaneurysm (RAM) can cause sub-inner limiting membrane (ILM) hemorrhage, leading to acute vision loss in the elderly. Vitrectomy has been established as an effective treatment to remove hemorrhage and facilitate visual recovery. Although optical coherence tomography (OCT) is useful for the diagnosis of sub-ILM hemorrhage before surgery, little is known about the postoperative OCT findings. Here, we retrospectively investigated the records of nine eyes of nine patients who underwent surgery for sub-ILM hemorrhage due to RAM rupture. On postoperative OCT, hyperreflectivity throughout the full thickness of the central fovea was observed in eight eyes (88.9%), and ...

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    21. Influence of protocol scan on choroidal vascularity measurements: a spectralis optical coherence tomography study

      Influence of protocol scan on choroidal vascularity measurements: a spectralis optical coherence tomography study

      Objectives To compare choroidal vascularity index (CVI) measurements using the automated image binarization algorithm in healthy subjects with two Spectralis spectral-domain optical coherence tomography (SD-OCT) protocol scans. Methods Sixty-nine eyes of 69 healthy volunteers were included in this cross-sectional prospective study. Two subsequent horizontal 20°line scans passing through the fovea were acquired with enhanced-depth imaging mode with high speed (HS) and high resolution (HR) protocol scans. CVI and its subcomponents were measured with the previously validated automated algorithm. Differences between choroidal measurements obtained with HS and HR protocol scans were evaluated with t-test and Bland & Altman plots. Results A ...

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    22. Optical coherence tomography—in situ and high-speed 3D imaging for laser materials processing

      Optical coherence tomography—in situ and high-speed 3D imaging for laser materials processing

      Exploiting Fourier-domain optical coherence tomography, a high-speed and real-time inspection of multi-photon 3D laser printing has been reported. We expect that this technique can be further extended to single shot compressive 3D imaging for studying the ultrafast dynamics of laser-matter interaction. Femtosecond lasers are essential tools for micro/nanoscale surface patterning 1 , as well as 3D lithography and printing 2 , 3 . Aiming for highly precision laser engineering, in situ and high-speed monitoring is of significance. While the wide-field microscopy enables a convenient in situ monitoring, it is limited to 2D imaging. The other advanced imaging methods, such as scanning electron ...

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    23. Inflation of test accuracy due to data leakage in deep learning-based classification of OCT images

      Inflation of test accuracy due to data leakage in deep learning-based classification of OCT images

      Abstract In the application of deep learning on optical coherence tomography (OCT) data, it is common to train classification networks using 2D images originating from volumetric data. Given the micrometer resolution of OCT systems, consecutive images are often very similar in both visible structures and noise. Thus, an inappropriate data split can result in overlap between the training and testing sets, with a large portion of the literature overlooking this aspect.

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    24. Prediction of visual function from automatically quantified optical coherence tomography biomarkers in patients with geographic atrophy using machine learning

      Prediction of visual function from automatically quantified optical coherence tomography biomarkers in patients with geographic atrophy using machine learning

      Geographic atrophy (GA) is a vision-threatening manifestation of age-related macular degeneration (AMD), one of the leading causes of blindness globally. Objective, rapid, reliable, and scalable quantification of GA from optical coherence tomography (OCT) retinal scans is necessary for disease monitoring, prognostic research, and clinical endpoints for therapy development. Such automatically quantified biomarkers on OCT are likely to further elucidate structure-function correlation in GA and thus the pathophysiological mechanisms of disease development and progression. In this work, we aimed to predict visual function with machine-learning applied to automatically acquired quantitative imaging biomarkers in GA. A post-hoc analysis of data from a ...

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    1-24 of 910 1 2 3 4 ... 36 37 38 »
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