1. Articles from Donald T. Miller

    1-24 of 38 1 2 »
    1. Research Associate / Postdoctoral Fellow in Adaptive Optics and Optical Coherence Tomography at Indiana University

      Research Associate / Postdoctoral Fellow in Adaptive Optics and Optical Coherence Tomography at Indiana University

      The Advanced Ophthalmic Imaging Laboratory at Indiana University is looking to fill a postdoctoral fellow or research associateposition. The successful candidate will join a team of scientists and engineers that are developing adaptive optics–optical coherence tomography (AO-OCT) for studying structure and function of the living human retina at the cellular level. The system is opening exciting new directions to study both normal and pathological vision. The laboratory ( www.opt.indiana.edu/dtmiller/Index.aspx ) is part of an active and well-funded community of vision scientists and engineers working in the areas of visual optics, retinal imaging, OCT, and adaptive ...

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    2. Method to investigate temporal dynamics of ganglion and other retinal cells in the living human eye

      Method to investigate temporal dynamics of ganglion and other retinal cells in the living human eye

      The inner retina is critical for visual processing, but much remains unknown about its neural circuitry and vulnerability to disease. A major bottleneck has been our inability to observe the structure and function of the cells composing these retinal layers in the living human eye. Here, we present a noninvasive method to observe both structural and functional information. Adaptive optics optical coherence tomography (AO-OCT) is used to resolve the inner retinal cells in all three dimensions and novel post processing algorithms are applied to extract structure and physiology down to the cellular level. AO-OCT captured the 3D mosaic of individual ...

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    3. Measuring polarization changes in the human outer retina with polarization‐sensitive optical coherence tomography

      Measuring polarization changes in the human outer retina with polarization‐sensitive optical coherence tomography

      Morphological changes in the outer retina such as drusen are established biomarkers to diagnose age‐related macular degeneration. However, earlier diagnosis might be possible by taking advantage of more subtle changes that accompany tissues that bear polarization‐altering properties. To test this hypothesis, we developed a method based on polarization‐sensitive optical coherence tomography with which volumetric data sets of the macula were obtained from 10 young (<25 years) and 10 older (>54 years) subjects. All young subjects and 5 of the older subjects had retardance values induced by the retinal pigment epithelium and Bruch's membrane (RPE‐BM) complex ...

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    4. Measuring polarization changes in the human outer retina with polarization-sensitive optical coherence tomography

      Measuring polarization changes in the human outer retina with polarization-sensitive optical coherence tomography

      Morphological changes in the outer retina such as drusen are established biomarkers to diagnose age-related macular degeneration. However earlier diagnosis might be possible by taking advantage of more subtle changes that accompany tissues that bear polarization-altering properties. To test this hypothesis, we developed a method based on polarization-sensitive optical coherence tomography with which volumetric data sets of the macula were obtained from 10 young (<25 yr) and 10 older (>54 yr) subjects. All young subjects and five of the older subjects had retardance values induced by the retinal pigment epithelium and Bruch's membrane (RPE-BM) complex that were just above ...

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    5. PhD Position in Advanced Ophthalmic Imaging at Indiana University

      PhD Position in Advanced Ophthalmic Imaging at Indiana University

      A PhD student position is available in Don Miller’s laboratory on advanced ophthalmic imaging at Indiana University ( www.opt.indiana.edu/dtmiller/Index.aspx ). The laboratory is looking for a highly motivated student in engineering, optical physics, or a related discipline with an interest to develop cutting-edge optical instrumentation to study noninvasively the retina at the cellular level. The laboratory’s primary focus is on the development and use of adaptive optics and optical coherence tomography (AO-OCT) for high-resolution retinal imaging, technologies the laboratory has been advancing for almost two decades. Our most recent work can be found in ...

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    6. Imaging and quantifying ganglion cells and other transparent neurons in the living human retina [Engineering]

      Imaging and quantifying ganglion cells and other transparent neurons in the living human retina [Engineering]

      Ganglion cells (GCs) are fundamental to retinal neural circuitry, processing photoreceptor signals for transmission to the brain via their axons. However, much remains unknown about their role in vision and their vulnerability to disease leading to blindness. A major bottleneck has been our inability to observe GCs and their degeneration in the living human eye. Despite two decades of development of optical technologies to image cells in the living human retina, GCs remain elusive due to their high optical translucency. Failure of conventional imaging—using predominately singly scattered light—to reveal GCs has led to a focus on multiply-scattered, fluorescence ...

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    7. Tracking dynamics of photoreceptor disc shedding with adaptive optics-optical coherence tomography

      Tracking dynamics of photoreceptor disc shedding with adaptive optics-optical coherence tomography

      Absorption of light by photoreceptors initiates vision, but also leads to accumulation of toxic photo-oxidative compounds in the photoreceptor outer segment (OS). To prevent this buildup, small packets of OS discs are periodically pruned from the distal end of the OS, a process called disc shedding. Unfortunately dysfunction in any part of the shedding event can lead to photoreceptor and RPE dystrophy, and has been implicated in numerous retinal diseases, including age related macular degeneration and retinitis pigmentosa. While much is known about the complex molecular and signaling pathways that underpin shedding, all of these advancements have occurred in animal ...

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    8. Adaptive optics optical coherence tomography angiography for morphometric analysis of choriocapillaris [Invited]

      Adaptive optics optical coherence tomography angiography for morphometric analysis of choriocapillaris [Invited]

      Histological studies have shown that morphometric changes at the microscopic level of choriocapillaris (CC) occur with aging and disease onset, and therefore may be sensitive biomarkers of outer retinal health. However, visualizing CC at this level in the living human eye is challenging because its microvascular is tightly interconnected and weakly reflecting. In this study, we address these challenges by developing and validating a method based on adaptive optics optical coherence tomography with angiography (AO-OCTA) that provides the necessary 3D resolution and image contrast to visualize and quantify these microscopic details. The complex network of anastomotic CC capillaries was successfully ...

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    9. PhD Position is Available in Don Miller’s Laboratory on Advanced Ophthalmic Imaging at Indiana University

      PhD Position is Available in Don Miller’s Laboratory on Advanced Ophthalmic Imaging at Indiana University

      A PhD student position is available in Don Miller’s laboratory on advanced ophthalmic imaging at Indiana University ( www.opt.indiana.edu/dtmiller/Index.aspx ). The laboratory is looking for a highly motivated student in optics, bioengineering, physics, computer science, or a related discipline to develop cutting edge optical instrumentation and software to conduct vision research. The student could also have a background in biological or medical vision who wants to use the laboratory’s sophisticated optical systems to study anatomical structures and physiological processes associated with normal and pathological vision. The lab’s primary focus is on the development ...

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    10. Photoreceptor disc shedding in the living human eye

      Photoreceptor disc shedding in the living human eye

      Cone photoreceptors undergo a daily cycle of renewal and shedding of membranous discs in their outer segments (OS), the portion responsible for light capture. These physiological processes are fundamental to maintaining photoreceptor health, and their dysfunction is associated with numerous retinal diseases. While both processes have been extensively studied in animal models and postmortem eyes, little is known about them in the living eye, in particular human. In this study, we report discovery of the optical signature associated with disc shedding using a method based on adaptive optics optical coherence tomography (AO-OCT) in conjunction with post-processing methods to track and ...

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    11. A Review of Adaptive Optics Optical Coherence Tomography: Technical Advances, Scientific Applications, and the Future

      A Review of Adaptive Optics Optical Coherence Tomography: Technical Advances, Scientific Applications, and the Future

      Purpose : Optical coherence tomography (OCT) has enabled “virtual biopsy” of the living human retina, revolutionizing both basic retina research and clinical practice over the past 25 years. For most of those years, in parallel, adaptive optics (AO) has been used to improve the transverse resolution of ophthalmoscopes to foster in vivo study of the retina at the microscopic level. Here, we review work done over the last 15 years to combine the microscopic transverse resolution of AO with the microscopic axial resolution of OCT, building AO-OCT systems with the highest three-dimensional resolution of any existing retinal imaging modality. Methods : We ...

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    12. Imaging human retinal pigment epithelium cells using adaptive optics optical coherence tomography

      Imaging human retinal pigment epithelium cells using adaptive optics optical coherence tomography

      Retinal pigment epithelium (RPE) cells are vital to health of the outer retina, but are often compromised in ageing and major ocular diseases that lead to blindness. Early manifestation of RPE disruption occurs at the cellular level, and while biomarkers at this scale hold considerable promise, RPE cells have proven extremely challenging to image in the living human eye. We present a novel method based on optical coherence tomography (OCT) equipped with adaptive optics (AO) that overcomes the associated technical obstacles. The method takes advantage of the 3D resolution of AO-OCT, but more critically sub-cellular segmentation and registration that permit ...

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    13. Imaging modal content of cone photoreceptors using adaptive optics optical coherence tomography

      Imaging modal content of cone photoreceptors using adaptive optics optical coherence tomography

      It has been long established that photoreceptors capture light based on the principles of optical waveguiding. Yet after decades of experimental and theoretical investigations considerable uncertainty remains, even for the most basic prediction as to whether photoreceptors support more than a single waveguide mode. To test for modal behavior in human cone photoreceptors, we took advantage of adaptive-optics optical coherence tomography (AO-OCT, λc=785 nm) to noninvasively image in three dimensions the reflectance profiles generated in the inner and outer segments (IS, OS) of cones. Mode content was examined over a range of cone diameters by imaging cones from 0 ...

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    14. Feature Of The Week 01/11/15: Indiana University Demonstrates Adaptive Optics Optical Coherence Tomography at 1 MHz

      Feature Of The Week 01/11/15: Indiana University Demonstrates Adaptive Optics Optical Coherence Tomography at 1 MHz

      Since its first report in 1991, OCT has undergone tremendous advances in almost all aspects of its underlying technologies and methods. For ophthalmic imaging, one of the most impactful advances has been the substantial improvement in image acquisition speed. Increased speed has enabled larger fields of view (FOV) of the retina to be imaged faster and with finer spatial and temporal sampling than ever before. These have greatly expanded the scientific and clinical utility of OCT and have opened new directions into imaging both structure and function of the retina. In this paper, we demonstrate a novel quad-spectrometer adaptive optics ...

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    15. Adaptive-optics optical coherence tomography processing using a graphics processing unit

      Adaptive-optics optical coherence tomography processing using a graphics processing unit

      Graphics processing units are increasingly being used for scientific computing for their powerful parallel processing abilities, and moderate price compared to super computers and computing grids. In this paper we have used a general purpose graphics processing unit to process adaptive-optics optical coherence tomography (AOOCT) images in real time. Increasing the processing speed of AOOCT is an essential step in moving the super high resolution technology closer to clinical viability.

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    16. Adaptive optics optical coherence tomography at 1 MHz

      Adaptive optics optical coherence tomography at 1 MHz

      Image acquisition speed of optical coherence tomography (OCT) remains a fundamental barrier that limits its scientific and clinical utility. Here we demonstrate a novel multi-camera adaptive optics (AO-)OCT system for ophthalmologic use that operates at 1 million A-lines/s at a wavelength of 790 nm with 5.3 μm axial resolution in retinal tissue. Central to the spectral-domain design is a novel detection channel based on four high-speed spectrometers that receive light sequentially from a 1 × 4 optical switch assembly. Absence of moving parts enables ultra-fast (50ns) and precise switching with low insertion loss (−0.18 dB per channel ...

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    17. Handbook of Retinal OCT: Optical Coherence Tomography

      Handbook of Retinal OCT: Optical Coherence Tomography

      In a little over two decades, optical coherence tomography (OCT) has become an indispensable imaging diagnostic service in eye care. This dramatic rise has been accompanied by a stream of OCT books from hardcore engineering to clinical use. It is on this front that the Handbook of Retinal OCT makes its debut. The book is an authoritative OCT guide put together by a team of international leaders in the eye care field. FIGURE. Philadelphia... Image Tools The preface describes an easy-to-read, brief but complete handbook of OCT images that is disease based and with minimal clinical description. The first few ...

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    18. Adaptive optics optical coherence tomography with dynamic retinal tracking

      Adaptive optics optical coherence tomography with dynamic retinal tracking

      Adaptive optics optical coherence tomography (AO-OCT) is a highly sensitive and noninvasive method for three dimensional imaging of the microscopic retina. Like all in vivo retinal imaging techniques, however, it suffers the effects of involuntary eye movements that occur even under normal fixation. In this study we investigated dynamic retinal tracking to measure and correct eye motion at KHz rates for AO-OCT imaging. A customized retina tracking module was integrated into the sample arm of the 2nd-generation Indiana AO-OCT system and images were acquired on three subjects. Analyses were developed based on temporal amplitude and spatial power spectra in conjunction ...

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    19. PhD student positions are available in Don Miller’s laboratory on advanced ophthalmic imaging at Indiana University

      PhD student positions are available in Don Miller’s laboratory on advanced ophthalmic imaging at Indiana University

      PhD student positions are available in Don Miller’s laboratory on advanced ophthalmic imaging at Indiana University ( www.opt.indiana.edu/dtmiller/Index.aspx ). The laboratory is looking for highly motivated students in optics, bioengineering, physics, computer science, or electrical engineering to develop cutting edge optical instrumentation and software to conduct vision research. Of particular interest is the use of optical coherence tomography (OCT) and adaptive optics. The lab is also interested in students with background in biological or medical vision who want to use the laboratory’s sophisticated optical systems to study anatomical structures and physiological processes associated with ...

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    20. Henle fiber layer phase retardation measured with polarization-sensitive optical coherence tomography

      Henle fiber layer phase retardation measured with polarization-sensitive optical coherence tomography

      Abstract: We developed a method based on polarization-sensitive optical coherence tomography (PS-OCT) to quantify the double pass phase retardation (DPPR) induced by Henle fiber layer in three subjects. Measurements of the retina were performed at a mean wavelength of 840 nm using two polarization states that were perpendicular in a Poincaré sphere representation and phase retardation contributions from tissue layers above and below the Henle fiber layer were excluded using appropriately placed reference and measurement points. These points were semi-automatically segmented from intensity data. Using a new algorithm to determine DPPR, the Henle fiber layer in three healthy subjects aged ...

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    21. Adaptive optics optical coherence tomography for measuring phase and reflectance dynamics of photoreceptors

      Adaptive optics optical coherence tomography for measuring phase and reflectance dynamics of photoreceptors

      Optical coherence tomography with adaptive optics (AO-OCT) is a noninvasive method for imaging the living retina at the microscopic level. We used AO-OCT technology to follow changes in cone photoreceptor outer segment (OS) length and reflectance. To substantially increase sensitivity of the length measurements, a novel phase retrieval technique was demonstrated, capable of detecting changes on a nanometer scale. We acquired volume videos of 0.65°x0.65° retinal patches at 1.5° temporal to the fovea over 75 and 105 minutes in two subjects. Volumes were dewarped and registered, after which the cone intensity, OS length, and referenced phase ...

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    22. Phase-sensitive imaging of the outer retina using optical coherence tomography and adaptive optics

      Phase-sensitive imaging of the outer retina using optical coherence tomography and adaptive optics
      The cone photoreceptor’s outer segment (OS) experiences changes in optical path length, both in response to visible stimuli and as a matter of its daily course of renewal and shedding. These changes are of interest, to quantify function in healthy cells and assess dysfunction in diseased ones. While optical coherence tomography (OCT), combined with adaptive optics (AO), has permitted unprecedented three-dimensional resolution in the living retina, it has not generally been able to measure these OS dynamics, whose scale is smaller than OCT’s axial resolution of a few microns. A possible solution is to take advantage of the ...
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    23. Imaging retinal nerve fiber bundles using optical coherence tomography with adaptive optics

      Imaging retinal nerve fiber bundles using optical coherence tomography with adaptive optics
      Early detection of axonal tissue loss in retinal nerve fiber layer (RNFL) is critical for effective treatment and management of diseases such as glaucoma. This study aims to evaluate the capability of ultrahigh-resolution optical coherence tomography with adaptive optics (UHR-AO-OCT) for imaging the RNFL axonal bundles (RNFBs) with 3 × 3 × 3 μm3 resolution in the eye. We used a research-grade UHR-AO-OCT system to acquire 3° × 3° volumes in four normal subjects and one subject with an arcuate retinal nerve fiber layer defect (n = 5; 29–62 years). Cross section (B-scans) and en face (C-scan) slices extracted from the volumes were ...
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    24. Imaging cone photoreceptors in three dimensions and in time using ultrahigh resolution optical coherence tomography with adaptive optics

      Imaging cone photoreceptors in three dimensions and in time using ultrahigh resolution optical coherence tomography with adaptive optics
      Cone photoreceptors in the living human eye have recently been imaged with micron-scale resolution in all three spatial dimensions using adaptive optics optical coherence tomography. While these advances have allowed non-invasive study of the three-dimensional structure of living human cones, studies of their function and physiology are still hampered by the difficulties to monitor the same cells over time. The purpose of this study is to demonstrate the feasibility of cone monitoring using ultrahigh-resolution adaptive optics optical coherence tomography. Critical to this is incorporation of a high speed CMOS camera (125 KHz) and a novel feature-based, image registration/dewarping algorithm ...
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    1-24 of 38 1 2 »
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