1. All Articles

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    1. Interplay between traveling wave propagation and amplification at the apex of the mouse cochlea

      Interplay between traveling wave propagation and amplification at the apex of the mouse cochlea

      Sounds entering the mammalian ear produce waves that travel from the base to the apex of the cochlea. An electro-mechanical active process amplifies traveling wave motions and enables sound processing over a broad range of frequencies and intensities. The cochlear amplifier requires combining the global traveling wave with the local cellular processes that change along the length of the cochlea given the gradual changes in hair cell and supporting cell anatomy and physiology. Thus, we measured basilar membrane (BM) traveling waves in vivo along the apical turn of the mouse cochlea using volumetric optical coherence tomography and vibrometry (VOCTV). We ...

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      Mentions: UCLA
    2. Postdoctoral Position in Advanced Ophthalmic imaging at Johns Hopkins

      Postdoctoral Position in Advanced Ophthalmic imaging at Johns Hopkins

      Description : The Yi and Johnson labs at the Johns Hopkins Wilmer Eye Institute and Dept of Biomedical Engineering are seeking candidates for one fully-funded postdoctoral position focused on developing multimodal 3D retinal imaging . The retina is the visual sensory organ and perceives >80% of information about the world around us. Retinal and optic nerve pathologies, such as glaucoma, can cause severe vision loss and blindness. Optical retinal imaging is particularly valuable in enabling high resolution rendering of 3D anatomical structures and functions using light, and thus plays important translational and clinical roles in evaluating and treating retinal disease. As an ...

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    3. Revealing how maltodextrin-containing droplets dry using optical coherence tomography

      Revealing how maltodextrin-containing droplets dry using optical coherence tomography

      Properties of powders produced from drying solute-containing droplets arise from the dynamic redistribution of solute during drying. While insights on the dynamic redistribution are instrumental for the rational design of powders and for the optimized operation of equipment such as spray dryers, experimental techniques that allow measuring the spatio-temporal concentration of solute in drying droplets are scarce. In this work, we explore and demonstrate the use of optical coherence tomography (OCT) to measure the spatio-temporal concentration of solute in drying droplets and the development of a solidifying shell at the liquid-air interface, using aqueous droplets of maltodextrin as a model ...

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    4. Repeatability and Agreement of Two Swept-Source Optical Coherence Tomographers for Anterior Segment Parameter Measurements

      Repeatability and Agreement of Two Swept-Source Optical Coherence Tomographers for Anterior Segment Parameter Measurements

      Purpose: The aim was to evaluate the repeatability and agreement of two swept-source optical coherence tomographers for anterior segment parameters in healthy subjects. Patients and methods: Automated mark of scleral spur and angle recess for the CASIA2 and manual mark of scleral spur and angle recess for the Anterion were performed, and then the measurement values of the related parameters were automatically generated. Subjects with pupil diameter (PD) differing by <15% between the 2 devices were included. PD, lens vault (LV), anterior chamber depth (ACD), angle to angle distance (ATA), anterior chamber width (ACW), anterior chamber angle (ACA), angle opening ...

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    5. The Role of OCT Criteria and Machine Learning in Multiple Sclerosis and Optic Neuritis Diagnosis

      The Role of OCT Criteria and Machine Learning in Multiple Sclerosis and Optic Neuritis Diagnosis

      Background and objectives: Recent studies have suggested that inter-eye differences (IEDs) in peripapillary retinal nerve fiber layer (pRNFL) or ganglion cell+inner plexiform (GCIPL) thickness by spectral-domain optical coherence tomography (SD-OCT) may identify people with a history of unilateral optic neuritis (ON). However, this requires further validation. Machine learning classification may be useful for validating thresholds for OCT IEDs and for examining added utility for visual function tests, such as low-contrast letter acuity (LCLA), in the diagnosis of people with multiple sclerosis (PwMS) and for unilateral ON history. Methods: Participants were from 11 sites within the International Multiple Sclerosis Visual ...

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    6. Ray Tracing versus Thin-Lens Formulas for IOL Power Calculation Using Swept-Source Optical Coherence Tomography Biometry

      Ray Tracing versus Thin-Lens Formulas for IOL Power Calculation Using Swept-Source Optical Coherence Tomography Biometry

      Purpose: To evaluate the ray tracing method's accuracy employing Okulix ray tracing software and thin-lens formulas to calculate intraocular lens (IOL) power using a swept-source optical coherence tomography (SS-OCT) biometer (OA2000). Methods: A total of 188 eyes from 180 patients were included in this study. An OA-2000 optical biometer was used to collect biometric data. The predicted postoperative refraction based on thin-lens formulas including SRK/T, Hoffer Q, Holladay 1, and Haigis formulas and the ray tracing method utilizing the OKULIX software was determined for each patient. To compare the accuracy of approaches, the prediction error and the absolute ...

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    7. Quantification method to objectively evaluate the fibrous structural status of tendons based on polarization-sensitive OCT

      Quantification method to objectively evaluate the fibrous structural status of tendons based on polarization-sensitive OCT

      Histological analysis is widely used to evaluate injured tendons; however, it has the limitation of being semi-quantitative. Hence, we developed a quantification method to objectively evaluate the fibrous structure of tendons, exhibiting the optical property of birefringence, using polarization-sensitive optical coherence tomography (PS-OCT). We used a partial-rupture rat model in which the middle 0.75 cm of the Achilles tendon was cut with a blade. Rats were sacrificed at 2, 4, or 6 weeks after the injury, and PS-OCT and histological analyses were performed. The PS-OCT phase retardation images and score well represented the structural changes of the injured tendon ...

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    8. Computational Fractional Flow Reserve From Coronary Computed Tomography Angiography-Optical Coherence Tomography Fusion Images in Assessing Functionally Significant Coronary Stenosis

      Computational Fractional Flow Reserve From Coronary Computed Tomography Angiography-Optical Coherence Tomography Fusion Images in Assessing Functionally Significant Coronary Stenosis

      Background: Coronary computed tomography angiography (CTA) and optical coherence tomography (OCT) provide additional functional information beyond the anatomy by applying computational fluid dynamics (CFD). This study sought to evaluate a novel approach for estimating computational fractional flow reserve (FFR) from coronary CTA-OCT fusion images. Methods: Among patients who underwent coronary CTA, 148 patients who underwent both pressure wire-based FFR measurement and OCT during angiography to evaluate intermediate stenosis in the left anterior descending artery were included from the prospective registry. Coronary CTA-OCT fusion images were created, and CFD was applied to estimate computational FFR. Based on pressure wire-based FFR as ...

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    9. Asymptomatic Unilateral Full-Thickness Macular Hole in a Patient with Bietti Crystalline Dystrophy During 13-Year Follow-up with Optical Coherence Tomography

      Asymptomatic Unilateral Full-Thickness Macular Hole in a Patient with Bietti Crystalline Dystrophy During 13-Year Follow-up with Optical Coherence Tomography

      A 39-year-old woman with progressive bilateral visual decline was diagnosed as having Bietti crystalline dystrophy in 2008. The disease course was monitored with optical coherence tomography until 2021. During the last routine eye examination in 2021, a full-thickness, slightly eccentric, visually asymptomatic macular hole with an intact foveola was noted in the left eye. No surgical treatment was recommended. The pathogenesis of full-thickness macular hole remained unclear as there were only subtle signs of prior very mild macular edema and vitreomacular interface abnormality. A degenerative process was also possible.

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    10. Structural and optical characterization of banknotes using spectral-domain optical coherence tomography

      Structural and optical characterization of banknotes using spectral-domain optical coherence tomography

      Counterfeiting of banknotes remains a severe threat to economic security and social stability. The characterization of banknote has mainly relied on the assessment of various security features applied to the surface of the note. However, the surface features are easy to forge and contain insufficient information to discover the source. In this paper, a novel approach for banknote characterization has been proposed by employing spectral-domain optical coherence tomography (SD-OCT) that can provide structural and optical features. Three groups of counterfeit Chinese 100 Yuan banknotes produced by different printing manners and one group of authentic banknotes were examined by SD-OCT without ...

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    11. Optical coherence tomography angiography of conjunctival and episcleral vessels in carotid cavernous fistula

      Optical coherence tomography angiography of conjunctival and episcleral vessels in carotid cavernous fistula

      A 44-year-old man, who had craniofacial trauma due to a motorcycle accident 1 month ago and cerebral arteriography that revealed a right carotid-cavernous fistula, presented with unilateral proptosis and diplopia. On ocular examination, the best-corrected visual acuity was 20/20 in both eyes. In the right eye, examination revealed restricted ocular motility, mild ptosis, 2-mm proptosis, dilation of the conjunctival and episcleral vessels in a medusa’s head ( Fig. 1A ). Intraocular pressure was 30 mmHg in the right eye. Dilated fundus examination showed dilated retinal veins but no venous stasis retinopathy, intraretinal hemorrhages, central retinal vein occlusion, choroidal folds, choroidal ...

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    12. Functional optical coherence tomography at altitude: retinal microvascular perfusion and retinal thickness at 3,800 meters

      Functional optical coherence tomography at altitude: retinal microvascular perfusion and retinal thickness at 3,800 meters

      Cerebral hypoxia is a serious consequence of several cardiorespiratory illnesses. Measuring the retinal microvasculature at high altitude provides a surrogate for cerebral microvasculature, offering potential insight into cerebral hypoxia in critical illness. Additionally, while sex-specific differences in cardiovascular diseases are strongly supported, few have focused on differences in ocular blood flow. We evaluated the retinal microvasculature in males (n=11) and females (n=7) using functional optical coherence tomography at baseline (1,130m) (Day 0), following rapid ascent (Day 2) and prolonged exposure (Day 9) to high altitude (3,800m). Retinal vascular perfusion density (rVPD; an index of total blood ...

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    13. Introduction to optical coherence elastography: tutorial

      Introduction to optical coherence elastography: tutorial

      Optical coherence elastography (OCE) has seen rapid growth since its introduction in 1998. The past few decades have seen tremendous advancements in the development of OCE technology and a wide range of applications, including the first clinical applications. This tutorial introduces the basics of solid mechanics, which form the foundation of all elastography methods. We then describe how OCE measurements of tissue motion can be used to quantify tissue biomechanical parameters. We also detail various types of excitation methods, imaging systems, acquisition schemes, and data processing algorithms and how various parameters associated with each step of OCE imaging can affect ...

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    14. Agreement Between Two Swept-source Optical Coherence Tomography Biometers and A Partial Coherence Interferometer

      Agreement Between Two Swept-source Optical Coherence Tomography Biometers and A Partial Coherence Interferometer

      Purpose To evaluate the level of agreement between ANTERION (Heidelberg Engineering, Heidelberg, Germany), OA-2000 (Tomey, Nagoya, Japan), and IOL Master 500 (Carl Zeiss Meditec AG, Jena, Germany). Methods Fifty-one eyes of 51 patients were included in the study. Flat and steep keratometry (K), vector component of astigmatism (J0 and J45), anterior chamber depth (ACD), and axial length (AL) were compared using the three devices. Repeated-measures analysis of variance was conducted to compare the mean values of the biometrics. Pearson’s correlation test was conducted to analyze the correlations of the measured values, and a Bland–Altman plot was used to ...

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    15. Volume Rendering of Deep Retinal Age-Related Microvascular Anomalies

      Volume Rendering of Deep Retinal Age-Related Microvascular Anomalies

      Purpose To characterize and distinguish non-neovascular deep retinal age-related microvascular anomalies (DRAMA) from type 3 macular neovascularization (MNV) using volume rendering of optical coherence tomography (OCT) and OCT angiography (OCTA). Design Retrospective, consecutive case series. Subjects Consecutive patients with age-related macular degeneration (AMD) exhibiting de novo non-neovascular abnormalities within the deep vascular plexus (DCP) on high-resolution (High-Res) spectral domain and swept-source OCT/OCTA. Patients with retinal vascular alterations attributable to other disease entities were excluded. Methods Complete ophthalmologic examination and multimodal imaging including confocal fundus photography (CFP), spectral domain OCT (SD-OCT), High-Res SD-OCT and OCTA, and volume-averaged swept-source OCTA (SS-OCTA ...

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    16. Cascade Optical Coherence Tomography (C-OCT) for Surface Form Metrology of - ProQuest

      Cascade Optical Coherence Tomography (C-OCT) for Surface Form Metrology of - ProQuest

      Freeform optical components enable dramatic advances in optical system performance and packaging. As the saying goes, “one cannot make what one cannot measure.” Surface form metrology of as-built freeform optics remains a challenge and an active area of research. In this dissertation, a novel cascade optical coherence tomography (C-OCT) technique was conceived towards addressing this metrology challenge. The C-OCT theoretical framework was developed, and a metrology system was built to demonstrate its working principle and metrology capability experimentally. Three significant areas were investigated to realize a C-OCT metrology system with nanometer-level measurement uncertainty. First, the sample arm requirements concerning telecentricity ...

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    17. Comparison of Anterior Segment Measurements with a New Multifunctional Unit and Five Other Devices

      Comparison of Anterior Segment Measurements with a New Multifunctional Unit and Five Other Devices

      Purpose To evaluate the clinical availability of a multifunctional ocular biometric unit, MR-6000 (Tomey Corporation, Nagoya, Japan), for simultaneous keratometry, tonometry, topography, and pachymetry evaluation, and compare anterior segment measurements with five other devices: autokeratometer (KR-1, Topcon, Tokyo, Japan), Scheimpflug camera (Pentacam HR, Oculus, Wetzlar, Germany), swept-source optical coherence tomography (IOLMaster 700, Carl Zeiss, Oberkochen, Germany), Placido disk scanning-slit topography (Orbscan II, Bausch & Lomb, NY, USA), and noncontact tonometry (FT-1000, Tomey Corporation). Methods Thirty patients (30 eyes) who visited our clinic for cataract surgery were examined using MR-6000 and the other devices. The mean keratometry (Km), central corneal thickness (CCT ...

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    18. Efficacy of Notal Vision Home OCT demonstrated by a series of scientific and clinical work

      Efficacy of Notal Vision Home OCT demonstrated by a series of scientific and clinical work

      Notal Vision, Inc. reported today that numerous scientific and clinical publications and presentations prove the feasibility and efficacy of their patient-operated, home-based optical coherence tomography (OCT) device. As part of a comprehensive remote monitoring service, which includes a monitoring center and artificial intelligence algorithms for information processing, the Notal Home OCT effectively monitors wet age-related macular degeneration (AMD) treatment between doctor’s office visits. Wet AMD is the leading cause of blindness in people over 50 in the United States. Several treatments have been developed over the last two decades and have proven to be extremely beneficial. However, therapy requires ...

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      Mentions: FDA Notal Vision
    19. Synergy Between morpHOlogical and inflammatoRy Evaluation in Predicting Long-term Coronary Plaque Progression

      Synergy Between morpHOlogical and inflammatoRy Evaluation in Predicting Long-term Coronary Plaque Progression

      Data from human autopsy studies have showed that thrombosis of a ruptured plaque with a large necrotic core, inflammatory cells and a thin fibrous cap, the so-called thin cap fibroatheroma (TCFA), represents the main mechanism for acute coronary syndrome (ACS). Optical coherence tomography (OCT) is an imaging technique that provides high-resolution, cross-sectional images of tissue in situ. The resolution of OCT (10 um) is appropriate for measuring a cap thickness less than65 μm, and even the plaque macrophage density. 68Ga-DOTA-(Tyr3)-octreotate/NaI3-octreotide(68Ga-DOTA-TATE/NOC) Positron Emission Tomography (PET)/Computed Tomography coronary angiography (CTCA), targeting the somatostatin receptor subtype-2 selectively ...

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    20. Altered ocular microvasculature in patients with systemic sclerosis and very early disease of systemic sclerosis using optical coherence tomography angiography

      Altered ocular microvasculature in patients with systemic sclerosis and very early disease of systemic sclerosis using optical coherence tomography angiography

      The vascular hypothesis of systemic sclerosis (SSc) would predict microvascular alterations should also affect anatomical regions like ocular microvasculature. The objective of this study was to evaluate retinal and choriocapillary vessel density (VD) in patients with definite SSc and very early disease of systemic sclerosis (VEDOSS) using optical coherence tomography angiography (OCTA). 22 eyes of 22 patients and 22 eyes of 22 healthy subjects were included in this study. Patients were classified into patients with definite SSc and patients with VEDOSS. VD data of the superficial OCT angiogram (OCTA-SCP), deep OCT angiogram (OCTA-DCP) and choriocapillaris (OCTA-CC) were analysed. VD in ...

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      Mentions: Visionix
    21. Assessment of macular findings by OCT angiography in patients without clinical signs of diabetic retinopathy: radiomics features for early screening of diabetic retinopathy

      Assessment of macular findings by OCT angiography in patients without clinical signs of diabetic retinopathy: radiomics features for early screening of diabetic retinopathy

      This cross-sectional study aimed to quantitatively analyze the optical coherence tomography angiography (OCTA) images using MATLAB-based software and evaluate the initial changes in macular vascular density and the distortion of the foveal avascular zone (FAZ), before the clinical appearance of diabetic retinopathy. For this purpose, 21 diabetic patients without any clinical features indicating DR, and 21 healthy individuals matched with patients based on their demographic characteristics were included. Macular thickness, macular vascular density, and morphological changes of FAZ were assessed using OCTA. The diagnostic ability of morphological parameters was evaluated by receiver operating curve analysis. The intraclass correlation coefficient (ICCC ...

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    22. Self-Examination Low-Cost Full-Field Optical Coherence Tomography (SELFF-OCT) for neovascular age-related macular degeneration: a cross-sectional diagnostic accuracy study

      Self-Examination Low-Cost Full-Field Optical Coherence Tomography (SELFF-OCT) for neovascular age-related macular degeneration: a cross-sectional diagnostic accuracy study

      Objectives: Self-Examination Low-Cost Full-Field Optical Coherence Tomography (SELFF-OCT) is a novel OCT technology that was specifically designed for home monitoring of neovascular age-related macular degeneration (AMD). First clinical findings have been reported before. This trial investigates an improved prototype for patients with AMD and focusses on device operability and diagnostic accuracy compared with established spectral-domain OCT (SD-OCT). Design: Prospective single-arm diagnostic accuracy study. Setting: Tertiary care centre (University Eye Clinic). Participants: 46 patients with age-related macular degeneration. Interventions: Patients received short training in device handling and then performed multiple self-scans with the SELFF-OCT according to a predefined protocol. Additionally, all ...

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    23. The Use of Optical Coherence Tomography to Demonstrate Dark and Light Adaptation in a Live Moth

      The Use of Optical Coherence Tomography to Demonstrate Dark and Light Adaptation in a Live Moth

      To work effectively, the eyes of nocturnal insects have a problem they must overcome. During the night, the light levels are low, so their eyes need to be very sensitive; but they also need a way of adapting to environmental light conditions, and protecting those sensitive organs, if a bright light is encountered. Human eyes have a pupil that changes size to regulate light input to the eye. Moths (Lepidoptera) use a light absorbing pigment that moves position to limit the light within the eye. This pigment migration is difficult to record because it is a dynamic process and will ...

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