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Biomedical Engineering and Bioengineering Commons™
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Articles 1 - 6 of 6
Full-Text Articles in Biomedical Engineering and Bioengineering
Automatic Detection Of Cone Photoreceptors In Split Detector Adaptive Optics Scanning Light Ophthalmoscope Images, David Cunefare, Robert F. Cooper, Brian P. Higgins, David F. Katz, Alfredo Dubra, Joseph Carroll, Sina Farsiu
Automatic Detection Of Cone Photoreceptors In Split Detector Adaptive Optics Scanning Light Ophthalmoscope Images, David Cunefare, Robert F. Cooper, Brian P. Higgins, David F. Katz, Alfredo Dubra, Joseph Carroll, Sina Farsiu
Biomedical Engineering Faculty Research and Publications
Quantitative analysis of the cone photoreceptor mosaic in the living retina is potentially useful for early diagnosis and prognosis of many ocular diseases. Non-confocal split detector based adaptive optics scanning light ophthalmoscope (AOSLO) imaging reveals the cone photoreceptor inner segment mosaics often not visualized on confocal AOSLO imaging. Despite recent advances in automated cone segmentation algorithms for confocal AOSLO imagery, quantitative analysis of split detector AOSLO images is currently a time-consuming manual process. In this paper, we present the fully automatic adaptive filtering and local detection (AFLD) method for detecting cones in split detector AOSLO images. We validated our algorithm …
Non-Common Path Aberration Correction In An Adaptive Optics Scanning Ophthalmoscope, Yusufu N. Sulai, Alfredo Dubra
Non-Common Path Aberration Correction In An Adaptive Optics Scanning Ophthalmoscope, Yusufu N. Sulai, Alfredo Dubra
Biomedical Engineering Faculty Research and Publications
The correction of non-common path aberrations (NCPAs) between the imaging and wavefront sensing channel in a confocal scanning adaptive optics ophthalmoscope is demonstrated. NCPA correction is achieved by maximizing an image sharpness metric while the confocal detection aperture is temporarily removed, effectively minimizing the monochromatic aberrations in the illumination path of the imaging channel. Comparison of NCPA estimated using zonal and modal orthogonal wavefront corrector bases provided wavefronts that differ by ~λ/20 in root-mean-squared (~λ/30 standard deviation). Sequential insertion of a cylindrical lens in the illumination and light collection paths of the imaging channel was used to compare image resolution …
Comparison Of Adaptive Optics Scanning Light Ophthalmoscopic Fluorescein Angiography And Offset Pinhole Imaging, Toco Y.P. Chui, Michael Dubow, Alexander Pinhas, Nishit Shah, Alexander Gan, Rishard Weitz, Yusufu N. Sulai, Alfredo Dubra, Richard B. Rosen
Comparison Of Adaptive Optics Scanning Light Ophthalmoscopic Fluorescein Angiography And Offset Pinhole Imaging, Toco Y.P. Chui, Michael Dubow, Alexander Pinhas, Nishit Shah, Alexander Gan, Rishard Weitz, Yusufu N. Sulai, Alfredo Dubra, Richard B. Rosen
Biomedical Engineering Faculty Research and Publications
Recent advances to the adaptive optics scanning light ophthalmoscope (AOSLO) have enabled finer in vivo assessment of the human retinal microvasculature. AOSLO confocal reflectance imaging has been coupled with oral fluorescein angiography (FA), enabling simultaneous acquisition of structural and perfusion images. AOSLO offset pinhole (OP) imaging combined with motion contrast post-processing techniques, are able to create a similar set of structural and perfusion images without the use of exogenous contrast agent. In this study, we evaluate the similarities and differences of the structural and perfusion images obtained by either method, in healthy control subjects and in patients with retinal vasculopathy …
In Vivo Imaging Of Human Retinal Microvasculature Using Adaptive Optics Scanning Light Ophthalmoscope Fluorescein Angiography, Alexander Pinhas, Michael Dubow, Nishit Shah, Toco Y.P. Chui, Drew Scoles, Yusufu N. Sulai, Rishard Weitz, Joseph B. Walsh, Joseph Carroll, Alfredo Dubra, Richard B. Rosen
In Vivo Imaging Of Human Retinal Microvasculature Using Adaptive Optics Scanning Light Ophthalmoscope Fluorescein Angiography, Alexander Pinhas, Michael Dubow, Nishit Shah, Toco Y.P. Chui, Drew Scoles, Yusufu N. Sulai, Rishard Weitz, Joseph B. Walsh, Joseph Carroll, Alfredo Dubra, Richard B. Rosen
Biomedical Engineering Faculty Research and Publications
The adaptive optics scanning light ophthalmoscope (AOSLO) allows visualization of microscopic structures of the human retina in vivo. In this work, we demonstrate its application in combination with oral and intravenous (IV) fluorescein angiography (FA) to the in vivo visualization of the human retinal microvasculature. Ten healthy subjects ages 20 to 38 years were imaged using oral (7 and/or 20 mg/kg) and/or IV (500 mg) fluorescein. In agreement with current literature, there were no adverse effects among the patients receiving oral fluorescein while one patient receiving IV fluorescein experienced some nausea and heaving. We determined that all retinal capillary …
In Vivo Dark-Field Imaging Of The Retinal Pigment Epithelium Cell Mosaic, Drew Scoles, Yusufu N. Sulai, Alfredo Dubra
In Vivo Dark-Field Imaging Of The Retinal Pigment Epithelium Cell Mosaic, Drew Scoles, Yusufu N. Sulai, Alfredo Dubra
Biomedical Engineering Faculty Research and Publications
Non-invasive reflectance imaging of the human RPE cell mosaic is demonstrated using a modified confocal adaptive optics scanning light ophthalmoscope (AOSLO). The confocal circular aperture in front of the imaging detector was replaced with a combination of a circular aperture 4 to 16 Airy disks in diameter and an opaque filament, 1 or 3 Airy disks thick. This arrangement reveals the RPE cell mosaic by dramatically attenuating the light backscattered by the photoreceptors. The RPE cell mosaic was visualized in all 7 recruited subjects at multiple retinal locations with varying degrees of contrast and cross-talk from the photoreceptors. Various experimental …
First-Order Design Of A Reflective Viewfinder For Adaptive Optics Ophthalmoscopy, Alfredo Dubra, Yusufu N. Sulai
First-Order Design Of A Reflective Viewfinder For Adaptive Optics Ophthalmoscopy, Alfredo Dubra, Yusufu N. Sulai
Biomedical Engineering Faculty Research and Publications
Adaptive optics (AO) ophthalmoscopes with small fields of view have limited clinical utility. We propose to address this problem in reflective instruments by incorporating a viewfinder pupil relay designed by considering pupil and image centering and conjugation. Diverting light from an existing pupil optical relay to the viewfinder relay allows switching field of view size. Design methods that meet all four centering and conjugation conditions using either a single concave mirror or with two concave mirrors forming an off-axis afocal telescope are presented. Two different methods for calculating the focal length and orientation of the concave mirrors in the afocal …