1. Articles from Daniel J. Wahl

    1-5 of 5
    1. Pseudo-real-time retinal layer segmentation for high-resolution adaptive optics optical coherence tomography

      Pseudo-real-time retinal layer segmentation for high-resolution adaptive optics optical coherence tomography

      We present a pseudo-real-time retinal layer segmentation for high-resolution Sensorless Adaptive Optics-Optical Coherence Tomography (SAO-OCT). Our pseudo-real-time segmentation method is based on Dijkstra’s algorithm that uses the intensity of pixels and the vertical gradient of the image to find the minimum cost in a geometric graph formulation within a limited search region. It segments six retinal layer boundaries in an iterative process according to their order of prominence. The segmentation time is strongly correlated to the number of retinal layers to be segmented. Our program permits en face images to be extracted during data acquisition to guide the depth ...

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    2. Multi-scale and -contrast sensorless adaptive optics optical coherence tomography

      Multi-scale and -contrast sensorless adaptive optics optical coherence tomography

      Background: The roles of the retinal microvasculature and the retinal pigment epithelium (RPE) in maintaining the health and metabolic activity of the retina lend great clinical value to their high-resolution visualization. Methods: By integrating polarization diversity detection (PDD) into multi-scale and -contrast sensorless adaptive optics optical coherence tomography (MSC-SAO-OCT), we have developed a novel multi-contrast SAO OCT system for imaging pigment in the RPE as well as flow in the retinal capillaries using OCT angiography (OCTA). Aberration correction was performed based on the image quality using transmissive deformable optical elements. Results: MSC-SAO-OCTA imaging was performed at multiple fields-of-view (FOVs) with ...

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    3. Visible light sensorless adaptive optics for retinal structure and fluorescence imaging

      Visible light sensorless adaptive optics for retinal structure and fluorescence imaging

      Optical coherence tomography (OCT) has emerged as a powerful imaging instrument and technology in biomedicine. OCT imaging is predominantly performed using wavelengths in the near infrared; however, visible light (VIS) has been recently employed in OCT systems with encouraging results for high-resolution retinal imaging. Using a broadband supercontinuum VIS source, we present a sensorless adaptive optics (SAO) multimodal imaging system driven by VIS-OCT for volumetric retinal structural imaging, followed by the acquisition of fluorescence emission. The coherence-gated, depth-resolved VIS-OCT images used for image-guided SAO aberration correction enable high-resolution structural and fluorescence imaging.

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    4. Investigation of the effect of directional (off-axis) illumination on the reflectivity of retina layers in mice using swept-source optical coherence tomography

      Investigation of the effect of directional (off-axis) illumination on the reflectivity of retina layers in mice using swept-source optical coherence tomography

      Changes in visibility of the Henle fiber layer and photoreceptor bands of the human retina with illumination directionality have been reported in OCT clinical imaging. These are a direct consequence of the changes in back scattering due to fibrous tissue orientation and to waveguiding properties of the photoreceptors respectively. Here we report the preliminary results of a study on the effects of retinal images acquired with OCT of illumination directionality in the mouse retina. The quantitative assessment of the reflectivity of retinal layers of a BALB/c and WT pigmented mice was performed in-vivo using a swept-source optical coherence tomography ...

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    5. Adaptive optics with combined optical coherence tomography and scanning laser ophthalmoscopy for in vivo mouse retina imaging

      Adaptive optics with combined optical coherence tomography and scanning laser ophthalmoscopy for in vivo mouse retina imaging

      Optical coherence tomography (OCT) and scanning laser ophthalmoscopy (SLO) are two state-of-the-art imaging technologies commonly used to study retina. Adaptive Optics (AO) methodologies enable high-fidelity correction of ocular aberrations, resulting in improved resolution and sensitivity for both SLO and OCT systems. Here we present work integrating OCT into a previously described mouse retinal AO-SLO system, allowing simultaneous reflectance and fluorescence imaging. The new system allows simultaneous data acquisition of AO-SLO and AO-OCT, facilitating registration and comparison of data from both modalities. The system has data acquisition speed of 200 kHz A-scans/pixel, and high volumetric resolution.

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    1-5 of 5
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  2. Topics in the News

    1. (5 articles) Simon Fraser University
    2. (5 articles) Marinko V. Sarunic
    3. (3 articles) Oregon Health & Science University
    4. (3 articles) Yifan Jian
    5. (3 articles) Myeong Jin Ju
    6. (2 articles) UC Davis
    7. (2 articles) Robert J. Zawadzki
    8. (2 articles) Pengfei Zhang
    9. (2 articles) Yale University
    10. (1 articles) Shuichi Makita
    11. (1 articles) Yoshiaki Yasuno
    12. (1 articles) Medical University of Vienna
    13. (1 articles) Thomas Jefferson University
    14. (1 articles) University of Southern California
    15. (1 articles) Duke University
    16. (1 articles) Sharon F. Freedman
    17. (1 articles) Wolfgang Drexler
    18. (1 articles) Rainer A. Leitgeb
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    Adaptive optics with combined optical coherence tomography and scanning laser ophthalmoscopy for in vivo mouse retina imaging Investigation of the effect of directional (off-axis) illumination on the reflectivity of retina layers in mice using swept-source optical coherence tomography Visible light sensorless adaptive optics for retinal structure and fluorescence imaging Multi-scale and -contrast sensorless adaptive optics optical coherence tomography Pseudo-real-time retinal layer segmentation for high-resolution adaptive optics optical coherence tomography Ultra-high-resolution SD-OCM imaging with a compact polarization-aligned 840 nm broadband combined-SLED source Sparse Domain Gaussianization for Multi-variate Statistical Modeling of Retinal OCT Images Optical reflectance contrast of micro- and nano-structures revealed with intravital micro-OCT (Thesis) In vivo optical biopsy of choroidal osteoma: a swept source optical coherence tomography–based tumor characterization Morphological changes in intraretinal microvascular abnormalities after anti-VEGF therapy visualized on optical coherence tomography angiography SD-OCT peripapillary nerve fibre layer and ganglion cell complex parameters in glaucoma: principal component analysis Accuracy of optical coherence tomography for diagnosing glaucoma: an overview of systematic reviews