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    1. Significance of outer retinal undulation on preoperative optical coherence tomography in rhegmatogenous retinal detachment

      Significance of outer retinal undulation on preoperative optical coherence tomography in rhegmatogenous retinal detachment

      Rhegmatogenous retinal detachment (RRD) is a vision-threatening pathology. Optical coherence tomography (OCT) is useful for evaluating retinal damage and visual prognosis in patients with RRD. Outer retinal undulation (ORU) is often observed on preoperative OCT in RRD. Therefore, we evaluated the correlation between ORU seen on preoperative OCT and pre/post-operative factors in RRD. Patients with RRD (114 eyes) underwent reattachment surgery and ≥ 6 months of follow-up. According to the condition of the macula on preoperative OCT, cases were divided into macula-on RRD (65 eyes) or macula-off RRD (49 eyes). Patients were classified into acute (< 10 days), subacute (10–30 ...

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    2. 3D imaging of proximal caries in posterior teeth using optical coherence tomography

      3D imaging of proximal caries in posterior teeth using optical coherence tomography

      Optical coherence tomography (OCT) can create cross-sectional images of tooth without X-ray exposure. This study aimed to investigate the diagnostic accuracy of 3D imaging of OCT for proximal caries in posterior teeth. Thirty-six human molar teeth with 51 proximal surfaces visibly 6 intact, 16 slightly demineralized, and 29 distinct carious changes were mounted to take digital radiographs and 3D OCT images. The sensitivity, specificity and area under the receiver operating characteristic curve (AUC) for the diagnosis of enamel caries and dentin caries were calculated to quantify the diagnostic ability of 3D OCT in comparison with digital radiography. Diagnostic accuracy was ...

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    3. Repeatability of binarization thresholding methods for optical coherence tomography angiography image quantification

      Repeatability of binarization thresholding methods for optical coherence tomography angiography image quantification

      Binarization is a critical step in analysis of retinal optical coherence tomography angiography (OCTA) images, but the repeatability of metrics produced from various binarization methods has not been fully assessed. This study set out to examine the repeatability of OCTA quantification metrics produced using different binarization thresholding methods, all of which have been applied in previous studies, across multiple devices and plexuses. Successive 3 × 3 mm foveal OCTA images of 13 healthy eyes were obtained on three different devices. For each image, contrast adjustments, 3 image processing techniques (linear registration, histogram normalization, and contrast-limited adaptive histogram equalization), and 11 binarization ...

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    4. Normative data for optical coherence tomography in children: a systematic review

      Normative data for optical coherence tomography in children: a systematic review

      The purpose of this study is to systematically review the reported data of normal optical coherence tomography (OCT) results in the paediatric population. A systematic literature search was performed using the PubMed, Embase, and Web of Science databases, using the keywords “optical coherence tomography”; “normative data” or “healthy eyes”; “children” or “paediatric population”. Studies with at least 50 participants were included, irrespective of the OCT equipment employed. We excluded the OCT angiography studies or the studies investigating the choroidal thickness. Seventy-four studies were included in the final analysis and information on study design, number of participants, demographic characteristics, type of ...

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    5. Asymmetry analysis of optical coherence tomography angiography macular perfusion density measurements in preperimetric and perimetric glaucoma

      Asymmetry analysis of optical coherence tomography angiography macular perfusion density measurements in preperimetric and perimetric glaucoma

      Macular retinal layer thickness asymmetry indices, particularly for the ganglion cell layer, are promising early indicators of glaucomatous damage. We evaluated macular perfusion density asymmetry (MPDA) among normal, preperimetric glaucoma (PPG), and perimetric glaucoma (PG) eyes, and we tested the performance of MPDA in differentiating between control and glaucoma eyes with or without visual field (VF) defects. In this study, 116 eyes (39 normal, 27 PPG, and 50 PG eyes) with optical coherence tomography angiography images of the macula were analysed. No significant difference was found in outer and inner MPDA between the control and PPG groups. However, outer MPDA ...

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    6. Longitudinal assessment of optic nerve head changes using optical coherence tomography in a primate microbead model of ocular hypertension

      Longitudinal assessment of optic nerve head changes using optical coherence tomography in a primate microbead model of ocular hypertension

      In humans, the longitudinal characterisation of early optic nerve head (ONH) damage in ocular hypertension (OHT) is difficult as patients with glaucoma usually have structural ONH damage at the time of diagnosis. Previous studies assessed glaucomatous ONH cupping by measuring the anterior lamina cribrosa depth (LCD) and minimal rim width (MRW) using optical coherence tomography (OCT). In this study, we induced OHT by repeated intracameral microbead injections in 16 cynomolgus primates (10 unilateral; 6 bilateral) and assessed the structural changes of the ONH longitudinally to observe early changes. Elevated intraocular pressure (IOP) in OHT eyes was maintained for 7 months ...

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    7. Swept-source optical coherence tomography angiography findings in choroidal and retinal tumors

      Swept-source optical coherence tomography angiography findings in choroidal and retinal tumors

      Objectives To report the swept-source optical coherence tomography angiography (SS-OCTA) findings in choroidal and retinal tumors. Methods A retrospective noncomparative interventional case series of 60 eyes having various choroidal and retinal tumors imaged with SS-OCTA (Topcon DR1 Triton Plus, Tokyo, Japan) between September 2018 and February 2020 was conducted. Inclusion criteria were tumor thickness <4 mm, tumor base diameter <10 mm, and tumor location at the posterior pole. Results Choroidal nevi usually demonstrated well-defined borders, hyperreflective internal structure, and no outer retinal involvement on SS-OCTA. Choroidal melanoma, in contrast to nevi, usually had ill-defined borders ( p  = 0.018), mixed hyperreflective ...

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    8. Repeatability, reproducibility, and comparison of ocular biometry using a new optical coherence tomography-based system and another device

      Repeatability, reproducibility, and comparison of ocular biometry using a new optical coherence tomography-based system and another device

      Precise measurement of axial length before cataract surgery is necessary for the proper lens implantation. We included 100 eyes of 56 patients in the study. The mean age was 41 (15–84 years). Measurements of axial length, anterior chamber depth (ACD) carried out with the new Revo NX were compared with those obtained with the IOLMaster 500. Interoperator testing was performed on 56 eyes of 56 participants. To test repeatability, axial length, ACD, central corneal thickness, and lens thickness were used. Inter-operator reproducibility was also assessed. The results were evaluated using Bland–Altman analyses. The mean ACD measured with the ...

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    9. Repeatability and reproducibility of post-mortem central corneal thickness measurements using a portable optical coherence tomography system in humans: a prospective multicenter study

      Repeatability and reproducibility of post-mortem central corneal thickness measurements using a portable optical coherence tomography system in humans: a prospective multicenter study

      To assess the repeatability and reproducibility of post-mortem central corneal thickness (CCT) measurements made by the portable iVue spectra-domain (SD) optical coherence tomography OCT (Optovue Inc, Fremont, CA) system in humans, and to prospectively establish the time-course of CCT after death. In a prospective multicenter setting, CCT measurements were obtained from 58 human eyes at the following 16 time-points after death: immediately (within 2 h), and at each hour by the next 17 h. The range of CCT values for each subject was determined and longitudinal data were used to illustrate the variation in open and close eye mode. All ...

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      Mentions: Optovue
    10. Optical coherence tomography angiography in diabetes: focus on microaneurysms

      Optical coherence tomography angiography in diabetes: focus on microaneurysms

      The introduction of optical coherence tomography angiography (OCTA) has remarkably expanded our knowledge of the ocular vascular alterations occurring in diabetes. In this article, a review of the prominent OCTA findings in diabetes is followed by a description of salient histological and anatomical features of microaneurysms, essential for the proper interpretation of in vivo imaging of these retinal vascular abnormalities. The recent employment of a three-dimensional (3D) visualization in OCTA imaging is also discussed. The latter imaging technique has granted a detailed characterization of microaneurysms in vivo.

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    11. Comparison of foveal optical coherence tomography angiography findings between premature children with ROP and non-premature healthy children

      Comparison of foveal optical coherence tomography angiography findings between premature children with ROP and non-premature healthy children

      Our aim is to compare foveal microvascular structure, foveal retinal thickness, and best-corrected visual acuity (BCVA) in children with a history of premature retinopathy (ROP) and healthy children. It is also evaluated whether microvascular structural changes in the course of ROP had resulted from treatment modalities of ROP or the disease itself. Methods This is a cross-sectional observational comparative study. Seventy-one children were analyzed in four different groups: children treated with bevacizumab (18), or laser (19) for ROP; or spontaneously regressed disease (18) and non-premature healthy children (16). We analyzed foveal avascular zone (FAZ) and vessel densities (VDs) of the ...

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    12. Analysis of optical coherence angiography in cystoid macular oedema associated with gyrate atrophy

      Analysis of optical coherence angiography in cystoid macular oedema associated with gyrate atrophy

      Background To evaluate the relationship between superficial, deep foveal avascular zone (FAZ) and foveal cyst areas in eyes with cystoid macular oedema (CMO) associated with gyrate atrophy of the choroid and retina (GA). Methods This is a retrospective collaborative multicenter study of optical coherence tomography-angiography (OCTA) images in GA. Superficial and deep FAZ and foveal cyst were measured using Image J by two independent experts. Values were corrected for myopia magnification. These values were compared with age-matched controls from normative data. Results Twenty-three eyes from 12 patients with GA and CMO were included in the study. The mean ± standard deviation ...

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    13. Suspended scattering particles in motion using OCT angiography in branch retinal vein occlusion disease cases with cystoid macular edema

      Suspended scattering particles in motion using OCT angiography in branch retinal vein occlusion disease cases with cystoid macular edema

      We aimed to investigate the clinical implication of suspended scattering particles in motion (SSPiM) using optical coherence tomography angiography (OCTA) among branch retinal vein occlusion disease (BRVO) cases with macular edema (ME). Medical records of BRVO patients were reviewed. Central retinal thickness (CRT), ME type, and cyst size on optical coherence tomography images were evaluated before and after intravitreal bevacizumab injection. Nonperfusion area, SSPiM, and microvascular abnormalities in OCTA images were evaluated using a Heidelberg machine. SSPiM was identified in 24 of 56 cases. There were no differences in baseline characteristics between groups with and without SSPiM. Disease duration, disease-free ...

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    14. Effect of image quality fluctuations on the repeatability of thickness measurements in swept-source optical coherence tomography

      Effect of image quality fluctuations on the repeatability of thickness measurements in swept-source optical coherence tomography

      This study investigated the effect of image quality fluctuations on the repeatability of thickness measurements of the peripapillary retinal nerve fibre (PP-RNFL) and ganglion cell-inner plexiform (GC-IPL) layers using swept-source optical coherence tomography (SS-OCT). Three consecutive OCT scans each were performed on 56 healthy subject. Finally, 168 SS-OCT results were analysed. Based on the tertile values of the mean absolute difference of image quality score, all subjects were divided into the following three groups—low-(LIQD), moderate-(MIQD), and high-(HIQD) image quality score difference groups. A linear mixed model and intraclass correlation coefficients (ICCs) were used for analyses. Despite ...

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    15. Dynamic full-field optical coherence tomography: 3D live-imaging of retinal organoids

      Dynamic full-field optical coherence tomography: 3D live-imaging of retinal organoids

      Optical coherence tomography offers astounding opportunities to image the complex structure of living tissue but lacks functional information. We present dynamic full-field optical coherence tomography as a technique to noninvasively image living human induced pluripotent stem cell-derived retinal organoids. Coloured images with an endogenous contrast linked to organelle motility are generated, with submicrometre spatial resolution and millisecond temporal resolution, creating a way to identify specific cell types in living tissue via their function. The comprehension of the human body and its mechanisms at the subcellular scale is still an open area of research. During the seventeenth century, the first examinations ...

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    16. Optical coherence tomography angiographic findings of lamellar macular hole: comparisons between tractional and degenerative subtypes

      Optical coherence tomography angiographic findings of lamellar macular hole: comparisons between tractional and degenerative subtypes

      We investigated the microvascular changes in eyes with lamellar macular holes (LMHs) using optical coherence tomography angiography (OCTA), compare them between two subtypes of LMH. Tractional and degenerative LMH were differentiated based on the morphological characteristics of OCT. In OCTA images, foveal and parafoveal vessel density (VD) in the superficial and deep capillary plexus (SCP, DCP) and foveal avascular zone (FAZ) area were measured. Eyes that underwent vitrectomy for LMH were included in subgroup analysis. We analysed 63 LMH (42 tractional and 21 degenerative) eyes and 63 control eyes. Compared with degenerative LMH, tractional LMH had better BCVA ( p  = 0 ...

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    17. Cerebral tissue pO2 response to treadmill exercise in awake mice

      Cerebral tissue pO2 response to treadmill exercise in awake mice

      We exploited two-photon microscopy and Doppler optical coherence tomography to examine the cerebral blood flow and tissue pO 2 response to forced treadmill exercise in awake mice. To our knowledge, this is the first study performing both direct measure of brain tissue pO 2 during acute forced exercise and underlying microvascular response at capillary and non-capillary levels. We observed that cerebral perfusion and oxygenation are enhanced during running at 5 m/min compared to rest. At faster running speeds (10 and 15 m/min), decreasing trends in arteriolar and capillary flow speed were observed, which could be due to cerebral ...

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    18. A neurovascular high-frequency optical coherence tomography system enables in situ cerebrovascular volumetric microscopy

      A neurovascular high-frequency optical coherence tomography system enables in situ cerebrovascular volumetric microscopy

      Intravascular imaging has emerged as a valuable tool for the treatment of coronary and peripheral artery disease; however, no solution is available for safe and reliable use in the tortuous vascular anatomy of the brain. Endovascular treatment of stroke is delivered under image guidance with insufficient resolution to adequately assess underlying arterial pathology and therapeutic devices. High-resolution imaging, enabling surgeons to visualize cerebral arteries' microstructure and micron-level features of neurovascular devices, would have a profound impact in the research, diagnosis, and treatment of cerebrovascular diseases. Here, we present a neurovascular high-frequency optical coherence tomography (HF-OCT) system, including an imaging console ...

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    19. In vivo imaging of the hyaloid vascular regression and retinal and choroidal vascular development in rat eyes using optical coherence tomography angiography

      In vivo imaging of the hyaloid vascular regression and retinal and choroidal vascular development in rat eyes using optical coherence tomography angiography

      This study investigates the hyaloid vascular regression and its relationship to the retinal and choroidal vascular developments using optical coherence tomography angiography (OCTA). Normal and oxygen-induced retinopathy (OIR) rat eyes at postnatal day 15, 18, 21, and 24 were longitudinally imaged using OCTA. At each day, two consecutive imaging for visualizing the hyaloid vasculature and the retinal and choroidal vasculatures were conducted. The hyaloid vessel volume and the retinal and choroidal vessel densities were measured. The hyaloid vessel volumes gradually decreased during the regression, although the OIR eyes exhibited large vessel volumes at all time points. A spatial relationship between ...

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    20. Live imaging and functional changes of the inner ear in an animal model of Meniere’s disease

      Live imaging and functional changes of the inner ear in an animal model of Meniere’s disease

      The symptoms of Meniere’s disease (MD) are generally considered to be related to endolymphatic hydrops (EH). There are many recent reports supporting the possibility that vasopressin (VP) is closely linked to the formation of EH in Meniere’s disease. Based on this, we developed a clinically relevant animal model of Meniere’s disease in which a VP type 2 receptor agonist was administered after electrocauterization of the endolymphatic sac. We report live imaging of the internal structure, and functional changes of the inner ear after electrocauterization of the endolymphatic sac and administration of a VP type 2 receptor agonist ...

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    21. Histological validation of in vivo assessment of cancer tissue inhomogeneity and automated morphological segmentation enabled by Optical Coherence Elastography

      Histological validation of in vivo assessment of cancer tissue inhomogeneity and automated morphological segmentation enabled by Optical Coherence Elastography

      We present a non-invasive (albeit contact) method based on Optical Coherence Elastography (OCE) enabling the in vivo segmentation of morphological tissue constituents, in particular, monitoring of morphological alterations during both tumor development and its response to therapies. The method uses compressional OCE to reconstruct tissue stiffness map as the first step. Then the OCE-image is divided into regions, for which the Young’s modulus (stiffness) falls in specific ranges corresponding to the morphological constituents to be discriminated. These stiffness ranges (characteristic "stiffness spectra") are initially determined by careful comparison of the "gold-standard" histological data and the OCE-based stiffness map for ...

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    22. Ultrathin monolithic 3D printed optical coherence tomography endoscopy for preclinical and clinical use

      Ultrathin monolithic 3D printed optical coherence tomography endoscopy for preclinical and clinical use

      Preclinical and clinical diagnostics increasingly rely on techniques to visualize internal organs at high resolution via endoscopes. Miniaturized endoscopic probes are necessary for imaging small luminal or delicate organs without causing trauma to tissue. However, current fabrication methods limit the imaging performance of highly miniaturized probes, restricting their widespread application. To overcome this limitation, we developed a novel ultrathin probe fabrication technique that utilizes 3D microprinting to reliably create side-facing freeform micro-optics (<130 µm diameter) on single-mode fibers. Using this technique, we built a fully functional ultrathin aberration-corrected optical coherence tomography probe. This is the smallest freeform 3D imaging probe ...

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    23. Analysis of the foveal microvasculature in sickle cell disease using swept-source optical coherence tomography angiography

      Analysis of the foveal microvasculature in sickle cell disease using swept-source optical coherence tomography angiography

      Ischemic microangiopathy was clearly identified in sickle cell disease (SCD) using fluorescein angiography. A prospective observational clinical study was conducted to assess the foveal avascular zone (FAZ) area and explore perifoveal microvasculature changes in the superficial (SCP) and deep (DCP) capillary plexus using optical coherence tomography angiography (OCTA) and compare two genotypes—HbS/HbS (HbSS) and HbS/HbC (HbSC)-to control. All consecutive patients with electrophoretic confirmation of SCD were included. Swept-source OCTA scans (Triton Plus, Topcon, Tokyo, Japan) with a 3 × 3-mm scanning area and ultra-wide field (UWF) retinography (California, Optos, Fife, Scotland) were recorded for all patients. For ...

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    24. Advances and potential new developments in imaging techniques for posterior uveitis. Part 1: noninvasive imaging methods

      Advances and potential new developments in imaging techniques for posterior uveitis. Part 1: noninvasive imaging methods

      The aim of this review was to identify the imaging methods at our disposal to optimally manage posterior uveitis at the present time. The focus was put on methods that have become available since the 1990s, some 30 years after fluorescein angiography had revolutionized imaging of posterior uveitis in particular imaging of the retinal vascular structures in the 1960s. We have focussed our review on precise imaging methods that have been standardized and validated and can be used universally thanks to commercially produced and available instruments for the diagnosis and follow-up of posterior uveitis. The first part of this imaging ...

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