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    1. Eckhaus Instability in the Fourier-Domain Mode Locked Fiber Laser Cavity

      Eckhaus Instability in the Fourier-Domain Mode Locked Fiber Laser Cavity

      High frequency fluctuation in the optical signal generated in Fourier-Domain Mode Locked fiber laser (FDML-FL), which is the major problem and degrades the laser performance, is not yet fully analyzed or studied. The basic theory which is causing this high frequency fluctuation is required to clearly understand its dynamics and to control it for various applications. In this letter, by analyzing the signal and system dynamics of FDML-FL, we theoretically demonstrate that the high frequency fluctuation is induced by the intrinsic instability of frequency offset of the signal in cavity with nonlinear gain and spectral filter. Unlike the instabilities observed ...

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    2. Swept-Source Optical Coherence Tomography Angiography in West Nile Virus Chorioretinitis and Associated Occlusive Retinal Vasculitis

      Swept-Source Optical Coherence Tomography Angiography in West Nile Virus Chorioretinitis and Associated Occlusive Retinal Vasculitis

      A 65-year-old man with diabetes and a history of fever of unknown origin 2 weeks earlier complained of sudden decreased vision in the left eye. The patient was diagnosed with bilateral West Nile virus (WNV) chorioretinitis associated with occlusive retinal vasculitis in the left eye. Swept-source optical coherence tomography angiography (SS-OCTA) of the left eye showed extensive, well-delineated, hypointense non-perfusion areas and perifoveal capillary arcade disruption in the superficial capillary plexus, as well as larger non-perfusion areas, capillary rarefaction, and diffuse capillary network attenuation and disorganization in the deep capillary plexus. OCTA may be a valuable tool for noninvasively assessing ...

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    3. Optical Coherence Tomography Angiography of Retinal Cavernous Hemangioma

      Optical Coherence Tomography Angiography of Retinal Cavernous Hemangioma

      Retinal cavernous hemangioma is a rare, benign, retinal tumor characterized by angiomatous proliferation of vessels within the inner retina or the optic disc.1 Here we report a case of retinal cavernous hemangioma on the margin of the optic disc in the right eye of a 61-year-old asymptomatic female. The lesion was studied with multimodal imaging which included structural optical coherence tomography, fluorescein angiography, blue fundus auto-fluorescence, optical coherence tomography angiography (OCTA) (DRI OCT Triton; Topcon, Tokyo, Japan) and visual field examination. Blood circulation inside retinal cavernous hemangioma lesion is typically low-stagnant.2 However, OCTA demonstrated blood flow inside the ...

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    4. Distinguishing White Dot Syndromes With Patterns of Choroidal Hypoperfusion on Optical Coherence Tomography Angiography

      Distinguishing White Dot Syndromes With Patterns of Choroidal Hypoperfusion on Optical Coherence Tomography Angiography

      BACKGROUND AND OBJECTIVE: To compare patterns of choroidal hypoperfusion in white dot syndromes (WDS) using optical coherence tomography angiography (OCTA). PATIENTS AND METHODS: Consecutive patients with WDS were imaged with either the Zeiss AngioPlex OCT Angiography (Carl Zeiss AG, Oberkochen, Germany) or the AngioVue OCT Angiography (Optovue, Fremont, CA) from February to November 2016. Four patients with acute posterior multifocal placoid pigment epitheliopathy (APMPPE), birdshot chorioretinopathy (BCR), presumed ocular histoplasmosis syndrome (POHS), and multiple evanescent white dot syndrome (MEWDS) were selected. This study was approved by the institutional review board at Massachusetts Eye and Ear. RESULTS: Unique patterns of choroidal ...

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      Mentions: Optovue
    5. Feature of the Week 08/17/2017: In Vivo Assessment of Periodontal Structures and Measurement of Gingival Sulcus with Optical Coherence Tomography: A Pilot Study

      Feature of the Week 08/17/2017: In Vivo Assessment of Periodontal Structures and Measurement of Gingival Sulcus with Optical Coherence Tomography: A Pilot Study

      There has been increasing interest on the development of clinically acceptable, more sensitive and specific methods for non-invasive diagnosis in Periodontics. In this pilot study, the performance of an Optical Coherence Tomography (OCT) system in imaging periodontal structures in humans was evaluated. Gingival sulcus depth measurements were obtained and compared with traditional probes. In total, 445 sites of 23 periodontally healthy individuals were measured by 3 instruments: North Carolina manual probe, Florida automated probe and OCT at 1325 nm. To obtain quantitative measurements from OCT images, the gingival refractive index was also determined. Discomfort/pain perception and the duration of ...

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    6. Massachusetts General Hospital Receives NIH Grant for Multimodal Mapping of the Neurocircuitry of the Human Prefontal Cortex

      Massachusetts General Hospital Receives NIH Grant for Multimodal Mapping of the Neurocircuitry of the Human Prefontal Cortex

      Massachusetts General Hospital Receives a 2017 NIH Grant for $474,273 for Multimodal Mapping of the Neurocircuitry of the Human Prefontal Cortex. The principal investigator is Anastasia Yendiki. The program began in 2016 and ends in 2020. Below is a summary of the proposed work. The objective of the proposed research is to map the organization of human white matter (WM) with cutting-edge ex vivo imaging technologies. This work will produce microscopic-level information on several long-range WM projections, as well as a more targeted mapping of circuits that serve the prefrontal cortex (PFC). These circuits are of particular interest in ...

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    7. LX Medical Corporation Receives a NIH Grant for High-Resolution Multi-modality Endoscopic Imaging Probes for Diagnosing Rejection in Lung Transplant Recipients

      LX Medical Corporation Receives a NIH Grant for High-Resolution Multi-modality Endoscopic Imaging Probes for Diagnosing Rejection in Lung Transplant Recipients

      LX Medical Corporation Receives a 2017 NIH Grant for $223,403 for High-Resolution Multi-modality Endoscopic Imaging Probes for Diagnosing Rejection in Lung Transplant Recipients. The principal investigator is Andrei Vertikov. The program began in 2017 and ends in 2018. Below is a summary of the proposed work. Lung transplantation is increasingly used to treat patients with end-stage lung diseases. Complications frequently occur with chronic allograft rejection causing most of late morbidity and mortality in lung transplant recipients. Pathological manifestations of chronic rejection mostly affect small airways or bronchioles in the lung, often progressing undetected until the patient presents with an ...

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    8. New York University School of Medicine Receives NIH Grant for Novel Glaucoma Diagnostics for Structure and Function

      New York University School of Medicine Receives NIH Grant for Novel Glaucoma Diagnostics for Structure and Function

      New York University School of Medicine Receives a 2017 NIH Grant for $654,143 for Novel Glaucoma Diagnostics for Structure and Function. The principal investigator is Joel Schuman. The program began in 2016 and ends in 2019. Below is a summary of the proposed work. Glaucoma is a leading cause of blindness and visual morbidity. Because the disease causes irreversible damage to neural tissue it is of upmost importance to identify glaucoma and its progression at the earliest possible stages. Through advancements in the use of optical coherence tomography (OCT) and other technologies, the long-term goal of this research project ...

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    9. University of Alabama at Birmingham Receives NIH Grant for $43,191 for Occular Phenotyping Core

      University of Alabama at Birmingham Receives NIH Grant for $43,191 for Occular Phenotyping Core

      University of Alabama at Birmingham Receives a 2017 NIH Grant for $43,191 for Occular Phenotyping Core. The principal investigator is Timothy Kraft. A summary of the proposed work is given below. Non-invasive assessment of eye structure and function is essential to both basic and translational research in vision science. Widely used technologies include slit lamp for biomicroscopy of anterior and posterior segment, electroretinography (ERG, for massed retinal signal separable into components), optical coherence tomography (OCT) for display of layered tissues in posterior and anterior segments, imaging of the fundus via multiple modes of visualization (color, autofluorescence, dye-based angiography, infrared ...

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    10. ROLE OF INTRA CORONARY IMAGING AND PHYSIOLOGY IN DIAGNOSIS AND MANAGEMENT OF CORONARY ARTERY DISEASE

      ROLE OF INTRA CORONARY IMAGING AND PHYSIOLOGY IN DIAGNOSIS AND MANAGEMENT OF CORONARY ARTERY DISEASE

      Coronary artery disease (CAD) is the leading cause of death in the Indo-Pakistan subcontinent as well as globally. Coronary angiography is considered the gold standard test for the diagnosis of CAD. Therefore, an accurate interpretation of coronary angiography is of paramount importance in decision-making to treat patients with CAD. Coronary angiography has the inherent limitation of being a two-dimensional X-Ray lumenogram of a complex three-dimensional vascular structure. Visual assessment of angiogram can lead to both inter- and intra-observer variability in the assessment of the severity and extent of the disease which can lead to differences in management strategies. This issue ...

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    11. Early detection of radiation maculopathy using OCTA imaging: a case report

      Early detection of radiation maculopathy using OCTA imaging: a case report

      Objective To report the case of a 62-year-old female treated with proton beam radiotherapy for a choroidal melanoma. Results After irradiation, the patient was followed-up regularly. Although clinical examination and spectral domain optical coherence tomography (OCT) showed no signs of radiation maculopathy, OCT angiography (OCTA) enabled detection of abnormalities (rarefaction of the vessel at both retinal capillary plexuses) probably related to the radiation maculopathy. Conclusion OCTA could help in the early detection of radiation maculopathy. This could be an important tool to monitor patients and discuss earlier treatments.

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    12. Optical sectioning in induced coherence tomography with frequency-entangled photons

      Optical sectioning in induced coherence tomography with frequency-entangled photons

      We demonstrate an experimental configuration to perform optical sectioning of a sample based on the concept of induced coherence [Zou et al., Phys. Rev. Lett. 67, 3187 (1991)]. This can be viewed as a new type of optical coherence tomography scheme, where different reflectivities of the sample under study translates into changes of the degree of first-order coherence between two beams. The induced coherence tomography scheme proposed here uses frequency-entangled photons embedded in a nonlinear interferometer. As practical advantage the scheme allows probing the sample with one wavelength and measuring light with another wavelength. In a bio-imaging scenario, this would ...

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    13. Optical coherence tomography imaging of cranial meninges post brain injury in vivo

      Optical coherence tomography imaging of cranial meninges post brain injury in vivo

      We report a new application of optical coherence tomography (OCT) to investigate the cranial meninges in an animal model of brain injury in vivo. The injury is induced in a mouse due to skull thinning, in which the repeated and excessive drilling exerts mechanical stress on the mouse brain through the skull, resulting in acute and mild brain injury. Transcranial OCT imaging reveals an interesting virtual space between the cranial meningeal layers post skull thinning, which is gradually closed within hours. The finding suggests a promise of OCT as an effective tool to monitor the mechanical trauma in the small ...

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    14. Two-year Results after Deep Sclerectomy with Non-absorbable Uveoscleral Implant (Esnoper-Clip): Surgical Area Analysis Using Anterior-segment Optical Coherence Tomography

      Two-year Results after Deep Sclerectomy with Non-absorbable Uveoscleral Implant (Esnoper-Clip): Surgical Area Analysis Using Anterior-segment Optical Coherence Tomography

      Purpose: To report two years results of deep sclerectomy (DS) with mitomycin C and the uveoscleral implant Esnoper-Clip (AJL Ophthalmics. Alava, Spain), a non-absorbable hema implant, and the morphological analysis of the surgical area with anterior segment optical coherence tomography (AS-OCT). Methods: Forty-one eyes of 41 patients with medically uncontrolled open angle glaucoma (OAG) who underwent DS with the uveoscleral implant were included in this prospective interventional study. Patients were recruited and selected sequentially. All patients were followed at least for 12 months and 36 of them for 24 months. Absolute success was defined as IOP <=18 mmHg and >=20 ...

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    15. Depth-resolved local reflectance spectra measurements in full-field optical coherence tomography

      Depth-resolved local reflectance spectra measurements in full-field optical coherence tomography

      Full-field optical coherence tomography (FF-OCT) is a widely used technique for applications such as biological imaging, optical metrology, and materials characterization, providing structural and spectral information. By spectral analysis of the backscattered light, the technique of spectroscopic-OCT enables the differentiation of structures having different spectral properties, but not the determination of their reflectance spectrum. For surface measurements, this can be achieved by applying a Fourier transform to the interferometric signals and using an accurate calibration of the optical system. An extension of this method is reported for local spectroscopic characterization of transparent samples and in particular for the determination of ...

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    16. Optical Coherence Tomography Analysis Based Prediction of Humphrey 24-2 Visual Field Thresholds in Patients With Glaucoma

      Optical Coherence Tomography Analysis Based Prediction of Humphrey 24-2 Visual Field Thresholds in Patients With Glaucoma

      Purpose : A pilot study showed that prediction of individual Humphrey 24-2 visual field (HVF 24-2) sensitivity thresholds from optical coherence tomography (OCT) image analysis is possible. We evaluate performance of an improved approach as well as 3 other predictive algorithms on a new, fully independent set of glaucoma subjects. Methods : Subjects underwent HVF 24-2 and 9-field OCT (Heidelberg Spectralis) testing. Nerve fiber (NFL), and ganglion cell and inner plexiform (GCL+IPL) layers were cosegmented and partitioned into 52 sectors matching HVF 24-2 test locations. The Wilcoxon rank sum test was applied to test correlation R , root mean square error (RMSE ...

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    17. Evaluation of myopia on retinal nerve fiber layer thickness measured by Spectralis optical coherence tomography

      Evaluation of myopia on retinal nerve fiber layer thickness measured by Spectralis optical coherence tomography

      The aim of the present study was to evaluate the retinal nerve fiber layer (RNFL) thickness of myopic subjects using Spectralis optical coherence tomography (OCT) and to determine variations with age and sex. A total of 271 Chinese participants with a spherical equivalent <+0.50 diopters were enrolled in the research. All subjects underwent a full ophthalmic examination. RNFL thickness was measured and compared according to sex, age and spherical equivalent. No significant difference was demonstrated between RNFL thickness in males and females. No significant difference was observed between RNFL thickness of the two age groups (≤12 years old and ...

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    18. Optical Coherence Tomography Angiography Vessel Density Measurements in Eyes with Primary Open Angle Glaucoma and Disc Hemorrhage

      Optical Coherence Tomography Angiography Vessel Density Measurements in Eyes with Primary Open Angle Glaucoma and Disc Hemorrhage

      Purpose: To compare the vessel density measurements of optic nerve head (ONH), peripapillary and macular regions in severity-matched primary open angle glaucoma (POAG) eyes with and without disc hemorrhage (DH) using optical coherence tomography (OCT) angiography (OCTA), and to compare their diagnostic abilities with that of the rim area, retinal nerve fiber layer and the ganglion cell complex thickness measurements on OCT. Methods: In a cross-sectional study, 66 eyes of 46 control subjects, 34 eyes of 33 POAG patients with DH (median mean deviation, MD: -3.7 dB) and 63 eyes of 43 POAG patients without DH (median MD: -3 ...

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    19. Extended depth of focus for coherence-based cellular imaging

      Extended depth of focus for coherence-based cellular imaging

      Improving lateral resolution for cross-sectional optical coherence tomography (OCT) imaging is difficult due to the rapid divergence of light once it is focused to a small spot. To overcome this obstacle, we introduce a fiber optics system that generates a coaxially focused multimode (CAFM) beam for depth of focus (DOF) extension. We fabricated a CAFM beam OCT probe and show that the DOF is more than fivefold that of a conventional Gaussian beam, enabling cross-sectional imaging of biological tissues with clearly resolved cellular and subcellular structures over more than a 400 μm depth range. The compact and straightforward design and ...

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    20. Optical Coherence Tomography Angiography in Children with Leber-Coats Disease

      Optical Coherence Tomography Angiography in Children with Leber-Coats Disease

      Introduction: The aim of this work was to describe the optical coherence tomography (OCT) angiography (OCTA) features in paediatric Leber-Coats disease. Methods: Three children presenting with unilateral, clinically active Leber-Coats disease were evaluated using spectral domain OCT and OCTA. OCT angiograms were analysed and compared with the current literature. Results: All 3 OCT angiograms showed that the vessels had lost most of their collateral branches and presented many loops. The capillaries were rarefied and anomalies in vessel size, vasodilatation, and macroaneurysms were evident. Conclusion: This is the first case series of OCTA performed in children with Leber-Coats disease. OCTA is ...

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    21. The use of optical coherence tomography in neuro-ophthalmology

      The use of optical coherence tomography in neuro-ophthalmology

      Purpose of review In the last decade, with the advances of optical coherence tomography (OCT) technology, different imaging protocols and analysis algorithms have been introduced to maximize the potential of this diagnostic tool in the evaluation of different eye diseases. This review aims to provide an update on these additional features, with respect to the management of a diverse range of neuro-ophthalmologic conditions. Recent findings Macular ganglion cell complex (mGCC) analysis has been shown to be superior to peripapillary retinal nerve fiber layer (pRNFL) analysis in certain settings, such as differentiating Leber's hereditary optic neuropathy from functional visual loss ...

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    22. The linear artifact in enhanced depth imaging spectral domain optical coherence tomography

      The linear artifact in enhanced depth imaging spectral domain optical coherence tomography

      Optical coherence tomography (OCT) is a valuable ancillary test in the diagnosis and management of chorioretinal disease. The evaluation of choroid thickness using OCT has become the focus of clinical applications. We report a linear artifact that acts as a confounding factor in choroidal thickness measurements by enhanced depth imaging OCT. We found that the linear artifact is located stably at a depth of 485  μ m beneath the retinal pigment epithelium in 81.88% of subjects. The study suggested that the linear artifact was a confounding factor in assessing choroidal thickness and that caution should be used in the interpretation ...

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    23. Postdoctoral Fellow, Bioengineering at University of Maryland - College Park

      Postdoctoral Fellow, Bioengineering at University of Maryland - College Park

      We are seeking a postdoctoral fellow to pursue research on developing novel optical imaging devices and applications on cancer diagnosis, functional brain imaging and tissue engineering. Candidates must hold a Ph.D. in engineering, physics, or related fields and have prior experience with Optics, OCT, Microscopy (e.g. fluorescence, confocal, Two-photon), and image analysis software development. Experience with cell culture and/or animals experiments is a plus. Please submit a cover letter with a brief description of research experience, interests, and career goals (≤ 2 pages), CV with complete list of publications, and contact information for 3 references in a single ...

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    24. Advances in glaucoma management blur the barriers between subspecialties

      Advances in glaucoma management blur the barriers between subspecialties

      Glaucoma management has undergone significant advancements in recent years. New minimally invasive surgical options have become available, filling in the gap between medical management and major surgeries such as trabeculectomy and tubes. On the diagnostic side, OCT technology has allowed a better understanding of the pathophysiology of glaucoma and more accurate monitoring of the effects of treatment, and has broadened the view to new imaging markers for progression. Glaucoma has opened up as a subspecialty to share areas of interest with other subspecialties and even other branches of medicine. “The life of a glaucoma specialist has become a lot busier ...

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