1. Articles from Morgan Heisler

    1-15 of 15
    1. Application of optical coherence tomography angiography in diabetic retinopathy: a comprehensive review

      Application of optical coherence tomography angiography in diabetic retinopathy: a comprehensive review

      Optical coherence tomography angiography (OCTA) is a noninvasive method that enables visualization of blood flow within retinal vessels down to the size of capillaries by detecting motion contrast from moving blood cells. OCTA provides a fast and safe procedure to assess retinal microvasculature with higher contrast and resolution than conventional fluorescence angiography . The different capillary plexuses are displayed separately and their perfusion density can be quantified. Imaging capabilities such as these have led to an emerging field of clinical application for OCTA in vascular diseases such as diabetic retinopathy (DR). Evaluation of parameters such as parafoveal capillary perfusion density could ...

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    2. Deep-Learning based Multiclass Retinal Fluid Segmentation and Detection in Optical Coherence Tomography Images using a Fully Convolutional Neural Network

      Deep-Learning based Multiclass Retinal Fluid Segmentation and Detection in Optical Coherence Tomography Images using a Fully Convolutional Neural Network

      As a non-invasive imaging modality, optical coherence tomography (OCT) can provide micrometer-resolution 3D images of retinal structures. These images can help reveal disease-related alterations below the surface of the retina, such as the presence of edema, or accumulation of fluid which can distort vision, and are an indication of disruptions in the vasculature of the retina. In this paper, a new framework is proposed for multiclass fluid segmentation and detection in the retinal OCT images. Based on the intensity of OCT images and retinal layer segmentations provided by a graph-cut algorithm, a fully convolutional neural network was trained to recognize ...

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    3. EN FACE OPTICAL COHERENCE TOMOGRAPHY AND OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY OF INNER RETINAL DIMPLES AFTER INTERNAL LIMITING MEMBRANE PEELING FOR FULL-THICKNESS MACULAR HOLES

      EN FACE OPTICAL COHERENCE TOMOGRAPHY AND OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY OF INNER RETINAL DIMPLES AFTER INTERNAL LIMITING MEMBRANE PEELING FOR FULL-THICKNESS MACULAR HOLES

      Purpose: To quantitatively and qualitatively evaluate the microvascular and structural abnormalities associated with inner retinal dimpling after internal limiting membrane peeling for full-thickness macular holes using sequential en face optical coherence tomography ( OCT ) and OCT angiography. Methods: Thirteen eyes of 13 patients with idiopathic full-thickness macular holes were enrolled in the study. Patients were treated with pars plana vitrectomy , internal limiting membrane peeling, and gas tamponade. Subjects were evaluated preoperatively and at postoperative Months 1, 3, and 6. At each visit, patients underwent a comprehensive ophthalmologic examination, en face OCT and OCT angiography. The morphology and number and proportionate area ...

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    4. Automated identification of cone photoreceptors in adaptive optics optical coherence tomography images using transfer learning

      Automated identification of cone photoreceptors in adaptive optics optical coherence tomography images using transfer learning

      Automated measurements of the human cone mosaic requires the identification of individual cone photoreceptors. The current gold standard, manual labeling, is a tedious process and can not be done in a clinically useful timeframe. As such, we present an automated algorithm for identifying cone photoreceptors in adaptive optics optical coherence tomography (AO-OCT) images. Our approach fine-tunes a pre-trained convolutional neural network originally trained on AO scanning laser ophthalmoscope (AO-SLO) images, to work on previously unseen data from a different imaging modality. On average, the automated method correctly identified 94% of manually labeled cones when compared to manual raters, from twenty ...

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    5. Label‐free volumetric imaging of conjunctival collecting lymphatics ex vivo by optical coherence tomography lymphangiography

      Label‐free volumetric imaging of conjunctival collecting lymphatics ex vivo by optical coherence tomography lymphangiography

      We employ optical coherence tomography (OCT) and optical coherence microscopy (OCM) to study conjunctival lymphatics in porcine eyes ex vivo . This study is a precursor to the development of in vivo imaging of the collecting lymphatics for potentially guiding and monitoring glaucoma filtration surgery. OCT scans at 1300 nm and higher‐resolution OCM scans at 785 nm reveal the lymphatic vessels via their optical transparency. Equivalent signal characteristics are also observed from blood vessels largely free of blood (and devoid of flow) in the ex vivo conjunctiva. In our lymphangiography, vessel networks were segmented by compensating the depth attenuation in ...

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    6. Effective bidirectional scanning pattern for optical coherence tomography angiography

      Effective bidirectional scanning pattern for optical coherence tomography angiography

      We demonstrate the utility of a novel scanning method for optical coherence tomography angiography (OCTA). Although raster scanning is commonly used for OCTA imaging, a bidirectional approach would lessen the distortion caused by galvanometer-based scanners as sources continue to increase sweep rates. As shown, a unidirectional raster scan approach has a lower effective scanning time than bidirectional approaches; however, a strictly bidirectional approach causes contrast variation along the B-scan direction due to the non-uniform time interval between B-scans. Therefore, a stepped bidirectional approach is introduced and successfully applied to retinal imaging in normal controls and in a pathological subject with ...

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    7. Quantitative comparisons between optical coherence tomography angiography and matched histology in the human eye

      Quantitative comparisons between optical coherence tomography angiography and matched histology in the human eye

      The aim was to quantitatively compare retinal vascular detail as seen on optical coherence tomography angiography (OCTA) and matched histology in the human eye. 13 normal human donor eyes were used. The central retinal artery was cannulated after which human packed red blood cells were perfused through the retinal vasculature. Retinal vessels were imaged using a custom-built OCTA device during red blood cell perfusion. The eye was subsequently perfused with endothelial cell antibodies and the flat-mounted retina studied histologically using a confocal scanning laser microscope. Qualitative and quantitative comparisons of retinal vascular information as seen on OCTA and histology from ...

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    8. Multiscale sensorless adaptive optics OCT angiography system for in vivo human retinal imaging

      Multiscale sensorless adaptive optics OCT angiography system for in vivo human retinal imaging

      We present a multiscale sensorless adaptive optics (SAO) OCT system capable of imaging retinal structure and vasculature with various fields-of-view (FOV) and resolutions. Using a single deformable mirror and exploiting the polarization properties of light, the SAO-OCT-A was implemented in a compact and easy to operate system. With the ability to adjust the beam diameter at the pupil, retinal imaging was demonstrated at two different numerical apertures with the same system. The general morphological structure and retinal vasculature could be observed with a few tens of micrometer-scale lateral resolution with conventional OCT and OCT-A scanning protocols with a 1.7-mm-diameter ...

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    9. Retinal Fluid Segmentation and Detection in Optical Coherence Tomography Images using Fully Convolutional Neural Network

      Retinal Fluid Segmentation and Detection in Optical Coherence Tomography Images using Fully Convolutional Neural Network

      As a non-invasive imaging modality, optical coherence tomography (OCT) can provide micrometer-resolution 3D images of retinal structures. Therefore it is commonly used in the diagnosis of retinal diseases associated with edema in and under the retinal layers. In this paper, a new framework is proposed for the task of fluid segmentation and detection in retinal OCT images. Based on the raw images and layers segmented by a graph-cut algorithm, a fully convolutional neural network was trained to recognize and label the fluid pixels. Random forest classification was performed on the segmented fluid regions to detect and reject the falsely labeled ...

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    10. Strip-based registration of serially acquired optical coherence tomography angiography

      Strip-based registration of serially acquired optical coherence tomography angiography

      The visibility of retinal microvasculature in optical coherence tomography angiography (OCT-A) images is negatively affected by the small dimension of the capillaries, pulsatile blood flow, and motion artifacts. Serial acquisition and time-averaging of multiple OCT-A images can enhance the definition of the capillaries and result in repeatable and consistent visualization. We demonstrate an automated method for registration and averaging of serially acquired OCT-A images. Ten OCT-A volumes from six normal control subjects were acquired using our prototype 1060-nm swept source OCT system. The volumes were divided into microsaccade-free en face angiogram strips, which were affine registered using scale-invariant feature transform ...

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    11. Anterior Segment Optical Coherence Tomography for Targeted Transconjunctival Suture Placement in Overfiltering Trabeculectomy Blebs

      Anterior Segment Optical Coherence Tomography for Targeted Transconjunctival Suture Placement in Overfiltering Trabeculectomy Blebs

      Purpose: To demonstrate the utility of swept-source anterior segment optical coherence tomography (SS-AS-OCT) in guiding placement of transconjunctival sutures in hypotonous patients after a trabeculectomy. Patients and Methods: This is a longitudinal case series of 10 eyes from 10 patients who required transconjunctival sutures after a trabeculectomy. SS-AS-OCT was used to aid in the placement of the sutures to improve the function of the overfiltering bleb. Results: SS-AS-OCT reliably identified localized areas of overfiltering, allowing for targeted suture placement in 8 eyes. The 2 eyes in which localized areas of overfiltering were not found required further surgical intervention. Conclusions: SS-AS-OCT ...

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    12. Quantitative Optical Coherence Tomography Angiography of Radial Peripapillary Capillaries in Glaucoma, Glaucoma Suspect and Normal Eyes

      Quantitative Optical Coherence Tomography Angiography of Radial Peripapillary Capillaries in Glaucoma, Glaucoma Suspect and Normal Eyes

      Purpose To evaluate the quantitative characteristics of the radial peripapillary capillary (RPC) network in glaucoma, glaucoma suspect and normal eyes using speckle variance optical coherence tomography angiography (OCT-A). To determine correlations between RPC density, nerve fibre layer (NFL) thickness and visual field indices. Design Cross sectional study. Methods OCT-A images of RPCs were acquired at a single institution using a custom-built 1060nm system from three groups: unilateral glaucoma (10 eyes from 5 subjects); glaucoma suspects (6 eyes from 3 subjects); and normal control eyes (16 eyes from 9 normal subjects). Peripapillary NFL thickness measurements were determined using spectral-domain OCT. Glaucoma ...

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    13. Lens-based wavefront sensorless adaptive optics swept source OCT

      Lens-based wavefront sensorless adaptive optics swept source OCT

      Optical coherence tomography (OCT) has revolutionized modern ophthalmology, providing depth resolved images of the retinal layers in a system that is suited to a clinical environment. Although the axial resolution of OCT system, which is a function of the light source bandwidth, is sufficient to resolve retinal features at a micrometer scale, the lateral resolution is dependent on the delivery optics and is limited by ocular aberrations. Through the combination of wavefront sensorless adaptive optics and the use of dual deformable transmissive optical elements, we present a compact lens-based OCT system at an imaging wavelength of 1060 nm for high ...

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    14. Quantitative Noninvasive Angiography of the Fovea Centralis Using Speckle Variance Optical Coherence Tomography

      Quantitative Noninvasive Angiography of the Fovea Centralis Using Speckle Variance Optical Coherence Tomography

      Purpose : To demonstrate the utility of speckle variance optical coherence tomography (svOCT), a noninvasive angiographic technique, for evaluating the foveal vasculature. Methods : Twelve normal human eyes were imaged with svOCT (1060-nm, 100-kHz custom-built system) and fluorescein angiography (FA; Topcon TRC-50DX with 5.0 megapixel resolution camera). Manual tracing techniques were used to quantify the foveal vasculature, including foveal avascular zone (FAZ) metrics (area, perimeter, greatest diameter, and lowest diameter). Reproducibility of these measurements was determined. The FAZ was imaged in 25 normal eyes using svOCT and 15 donor eyes using confocal scanning laser microscopy. Retinal capillary plexuses in donor eyes ...

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    15. Enhancing the visualization of human retina vascular networks by Graphics Processing Unit accelerated speckle variance OCT and graph cut retinal layer segmentation

      Enhancing the visualization of human retina vascular networks by Graphics Processing Unit accelerated speckle variance OCT and graph cut retinal layer segmentation

      We present a Graph Cut based image segmentation that was implemented on a Graphics Processing Unit for acceleration of processing retinal images acquired with OCT. We applied this work to generate a retinal thickness map, and for retinal layer segmentation to enhance the visualization of vasculature networks from distinct retinal capillary beds during acquisition using speckle variance OCT.

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    1-15 of 15
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    Enhancing the visualization of human retina vascular networks by Graphics Processing Unit accelerated speckle variance OCT and graph cut retinal layer segmentation Quantitative Noninvasive Angiography of the Fovea Centralis Using Speckle Variance Optical Coherence Tomography Lens-based wavefront sensorless adaptive optics swept source OCT Quantitative Optical Coherence Tomography Angiography of Radial Peripapillary Capillaries in Glaucoma, Glaucoma Suspect and Normal Eyes Anterior Segment Optical Coherence Tomography for Targeted Transconjunctival Suture Placement in Overfiltering Trabeculectomy Blebs Strip-based registration of serially acquired optical coherence tomography angiography Retinal Fluid Segmentation and Detection in Optical Coherence Tomography Images using Fully Convolutional Neural Network Multiscale sensorless adaptive optics OCT angiography system for in vivo human retinal imaging Quantitative comparisons between optical coherence tomography angiography and matched histology in the human eye Deep-Learning based Multiclass Retinal Fluid Segmentation and Detection in Optical Coherence Tomography Images using a Fully Convolutional Neural Network Measurement of the Shrinkage of Natural and Simulated Lesions on Root Surfaces using CP-OCT Optic-Net: A Novel Convolutional Neural Network for Diagnosis of Retinal Diseases from Optical Tomography Images