1
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Berkowitz ST, Lam S, Sternberg P, Patel SN, Finn AP. Time-driven Activity-based Costing Analysis of Fluorescein Angiography. Ophthalmol Retina 2023; 7:804-810. [PMID: 37244412 DOI: 10.1016/j.oret.2023.05.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 04/23/2023] [Accepted: 05/19/2023] [Indexed: 05/29/2023]
Abstract
PURPOSE To use electronic health record (EHR) time logs and time-driven activity-based costing (TDABC) to calculate the complete cost profile of office-based fluorescein angiography (FA). DESIGN Economic analysis. SUBJECTS Patients undergoing routine FA (Current Procedural Terminology [CPT] 92235) at Vanderbilt Eye Institute in fiscal year 2022. METHODS Process flow mapping for routine FA was used to define the care episode after manual observation. Deidentified time logs were sourced from the EHR and all manually validated to calculate durations for each stage. The cost of materials was calculated from internal financial figures. Cost per minute for space, equipment, and personnel were based on internal figures. Published fluorescein costs were used for base-case analysis with scenario analysis based on a range of internal figures from pharmacy quotes. These inputs were used for a TDABC analysis. MAIN OUTCOME MEASURES Time-driven activity-based costing of FA episode of care. Secondary scenario analyses focus on breakeven scenarios for key inputs, including medication costs RESULTS: Cost analysis of office-based FA resulted in an average total cost of $152.95 (nominal) per interpreted study per patient, which was $36.52 more than the maximum Medicare reimbursement for CPT 92235 in Mac Locality for Tennessee 10312 for fiscal year 2022 ($116.43; $76.11 [technical component] and $40.33 [physician component]). The negative contribution margin is strongly influenced by the cost of fluorescein, which comprises 39.8% of the episode costs, excluding overhead. CONCLUSIONS The current analysis here shows that the recently increased cost of fluorescein has driven up the cost of office-based FA relative to the current maximum allowable Medicare reimbursement, leading to a negative contribution margin and financial loss. Given conservative cost estimates here, it is unlikely for profitability to be achieved without changes in the cost of fluorescein or increased reimbursement. These results may be informative for policy discussion regarding appropriate reimbursement for codes using injectable fluorescein. FINANCIAL DISCLOSURE(S) Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.
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Affiliation(s)
- Sean T Berkowitz
- Department of Ophthalmology, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Shravika Lam
- Department of Ophthalmology, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Paul Sternberg
- Department of Ophthalmology, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Shriji N Patel
- Department of Ophthalmology, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Avni P Finn
- Department of Ophthalmology, Vanderbilt University Medical Center, Nashville, Tennessee.
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2
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Multi-modal and multi-scale clinical retinal imaging system with pupil and retinal tracking. Sci Rep 2022; 12:9577. [PMID: 35688890 PMCID: PMC9187716 DOI: 10.1038/s41598-022-13631-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Accepted: 05/17/2022] [Indexed: 11/08/2022] Open
Abstract
We present a compact multi-modal and multi-scale retinal imaging instrument with an angiographic functional extension for clinical use. The system integrates scanning laser ophthalmoscopy (SLO), optical coherence tomography (OCT) and OCT angiography (OCTA) imaging modalities and provides multi-scale fields of view. For high resolution, and high lateral resolution in particular, cellular imaging correction of aberrations by adaptive optics (AO) is employed. The entire instrument has a compact design and the scanning head is mounted on motorized translation stages that enable 3D self-alignment with respect to the subject's eye by tracking the pupil position. Retinal tracking, based on the information provided by SLO, is incorporated in the instrument to compensate for retinal motion during OCT imaging. The imaging capabilities of the multi-modal and multi-scale instrument were tested by imaging healthy volunteers and patients.
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3
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Bouma B, de Boer J, Huang D, Jang I, Yonetsu T, Leggett C, Leitgeb R, Sampson D, Suter M, Vakoc B, Villiger M, Wojtkowski M. Optical coherence tomography. NATURE REVIEWS. METHODS PRIMERS 2022; 2:79. [PMID: 36751306 PMCID: PMC9901537 DOI: 10.1038/s43586-022-00162-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Optical coherence tomography (OCT) is a non-contact method for imaging the topological and internal microstructure of samples in three dimensions. OCT can be configured as a conventional microscope, as an ophthalmic scanner, or using endoscopes and small diameter catheters for accessing internal biological organs. In this Primer, we describe the principles underpinning the different instrument configurations that are tailored to distinct imaging applications and explain the origin of signal, based on light scattering and propagation. Although OCT has been used for imaging inanimate objects, we focus our discussion on biological and medical imaging. We examine the signal processing methods and algorithms that make OCT exquisitely sensitive to reflections as weak as just a few photons and that reveal functional information in addition to structure. Image processing, display and interpretation, which are all critical for effective biomedical imaging, are discussed in the context of specific applications. Finally, we consider image artifacts and limitations that commonly arise and reflect on future advances and opportunities.
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Affiliation(s)
- B.E. Bouma
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA, USA,Institute for Medical Engineering and Physics, Massachusetts Institute of Technology, Cambridge, MA, USA,Harvard Medical School, Boston, MA, USA,Corresponding author:
| | - J.F. de Boer
- Department of Physics and Astronomy, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - D. Huang
- Casey Eye Institute, Oregon Health and Science University, Portland, OR, USA
| | - I.K. Jang
- Harvard Medical School, Boston, MA, USA,Cardiology Division, Massachusetts General Hospital, Boston, MA, USA
| | - T. Yonetsu
- Department of Cardiovascular Medicine, Tokyo Medical and Dental University
| | - C.L. Leggett
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN, USA
| | - R. Leitgeb
- Institute of Medical Physics, University of Vienna, Wien, Austria
| | - D.D. Sampson
- School of Physics and School of Biosciences and Medicine, University of Surrey, Guildford, United Kingdom
| | - M. Suter
- Harvard Medical School, Boston, MA, USA,Division of Pulmonary and Critical Care Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - B. Vakoc
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA, USA,Harvard Medical School, Boston, MA, USA
| | - M. Villiger
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA, USA,Harvard Medical School, Boston, MA, USA
| | - M. Wojtkowski
- Institute of Physical Chemistry and International Center for Translational Eye Research, Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw, Poland,Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, Torun, Poland
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4
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In vivo human retinal swept source optical coherence tomography and angiography at 830 nm with a CMOS compatible photonic integrated circuit. Sci Rep 2021; 11:21052. [PMID: 34702941 PMCID: PMC8548589 DOI: 10.1038/s41598-021-00637-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 10/15/2021] [Indexed: 11/29/2022] Open
Abstract
Photonic integrated circuits (PIC) provide promising functionalities to significantly reduce the size and costs of optical coherence tomography (OCT) systems. This paper presents an imaging platform operating at a center wavelength of 830 nm for ophthalmic application using PIC-based swept source OCT. An on-chip Mach–Zehnder interferometer (MZI) configuration, which comprises an input power splitter, polarization beam splitters in the sample and the reference arm, and a 50/50 coupler for signal interference represents the core element of the system with a footprint of only \documentclass[12pt]{minimal}
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\begin{document}$$(12 \times 5)\;{\text {mm}}^2$$\end{document}(12×5)mm2. The system achieves 94 dB imaging sensitivity with 750 \documentclass[12pt]{minimal}
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\begin{document}$$\upmu $$\end{document}μW on the sample, 50 kHz imaging speed and 5.5 \documentclass[12pt]{minimal}
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\begin{document}$$\upmu $$\end{document}μm axial resolution (in soft tissue). With this setup, in vivo human retinal imaging of healthy subjects was performed producing B-scans, three-dimensional renderings as well as OCT angiography. These promising results are significant prerequisites for further integration of optical and electronic building blocks on a single swept source-OCT PIC.
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5
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Park KS, Park E, Lee H, Lee HJ, Lee SW, Eom TJ. Phase stable swept-source optical coherence tomography with active mode-locking laser for contrast enhancements of retinal angiography. Sci Rep 2021; 11:16636. [PMID: 34404853 PMCID: PMC8371173 DOI: 10.1038/s41598-021-95982-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 07/30/2021] [Indexed: 11/23/2022] Open
Abstract
Swept-source optical coherence tomography (SS-OCT) is an attractive high-speed imaging technique for retinal angiography. However, conventional swept lasers vary the cavity length of the laser mechanically to tune the output wavelength. This causes sweep-timing jitter and hence low phase stability in OCT angiography. Here, we improve an earlier phase-stabilized, akinetic, SS-OCT angiography (OCTA) method by introducing coherent averaging. We develop an active mode-locking (AML) laser as a high phase-stable akinetic swept source for the OCTA system. The phase stability of the improved system was analyzed, and the effects of coherent averaging were validated using a retina phantom. The effectiveness of the coherent averaging method was further confirmed by comparing coherently and conventionally averaged en face images of human retinal vasculature for their contrast-to-noise ratio, signal-to-noise ratio, and vasculature connectivity. The contrast-to-noise ratio was approximately 1.3 times larger when applying the coherent averaging method in the human retinal experiment. Our coherent averaging method with the high phase-stability AML laser source for OCTA provides a valuable tool for studying healthy and diseased retinas.
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Affiliation(s)
- Kwan Seob Park
- Advanced Photonics Research Institute, Gwangju Institute of Science and Technology, 123 Cheomdan-gwagiro, Buk-gu, Gwangju, 61005, South Korea
| | - Eunwoo Park
- Advanced Photonics Research Institute, Gwangju Institute of Science and Technology, 123 Cheomdan-gwagiro, Buk-gu, Gwangju, 61005, South Korea
| | - Hwidon Lee
- Harvard Medical School, Boston, MA, 02115, USA.,Wellman Center for Photomedicine, Harvard Medical School and Massachusetts General Hospital, 40 Blossom Street, Boston, MA, 02114, USA
| | - Hyun-Ji Lee
- Safety Measurement Institute, Korea Research Institute of Standards and Science, 267 Gajeong-ro, Yuseong-gu, Daejeon, 34113, South Korea.,Department of Medical Physics, University of Science and Technology, 217 Gajeong-ro, Yuseong-gu, Daejeon, 34113, South Korea
| | - Sang-Won Lee
- Safety Measurement Institute, Korea Research Institute of Standards and Science, 267 Gajeong-ro, Yuseong-gu, Daejeon, 34113, South Korea.,Department of Medical Physics, University of Science and Technology, 217 Gajeong-ro, Yuseong-gu, Daejeon, 34113, South Korea
| | - Tae Joong Eom
- Advanced Photonics Research Institute, Gwangju Institute of Science and Technology, 123 Cheomdan-gwagiro, Buk-gu, Gwangju, 61005, South Korea.
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6
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Lejoyeux R, Benillouche J, Ong J, Errera MH, Rossi EA, Singh SR, Dansingani KK, da Silva S, Sinha D, Sahel JA, Freund KB, Sadda SR, Lutty GA, Chhablani J. Choriocapillaris: Fundamentals and advancements. Prog Retin Eye Res 2021; 87:100997. [PMID: 34293477 DOI: 10.1016/j.preteyeres.2021.100997] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 07/02/2021] [Accepted: 07/13/2021] [Indexed: 12/19/2022]
Abstract
The choriocapillaris is the innermost structure of the choroid that directly nourishes the retinal pigment epithelium and photoreceptors. This article provides an overview of its hemovasculogenesis development to achieve its final architecture as a lobular vasculature, and also summarizes the current histological and molecular knowledge about choriocapillaris and its dysfunction. After describing the existing state-of-the-art tools to image the choriocapillaris, we report the findings in the choriocapillaris encountered in the most frequent retinochoroidal diseases including vascular diseases, inflammatory diseases, myopia, pachychoroid disease spectrum disorders, and glaucoma. The final section focuses on the development of imaging technology to optimize visualization of the choriocapillaris as well as current treatments of retinochoroidal disorders that specifically target the choriocapillaris. We conclude the article with pertinent unanswered questions and future directions in research for the choriocapillaris.
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Affiliation(s)
| | | | - Joshua Ong
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Marie-Hélène Errera
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Ethan A Rossi
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; Department of Bioengineering, University of Pittsburgh Swanson School of Engineering, Pittsburgh, PA 15213, USA
| | - Sumit R Singh
- Jacobs Retina Center, Shiley Eye Institute, University of California San Diego, San Diego, CA, USA
| | - Kunal K Dansingani
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Susana da Silva
- Department of Ophthalmology and Department of Developmental Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Debasish Sinha
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; Department of Cell Biology and Center for Biologic Imaging, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - José-Alain Sahel
- Rothschild Foundation, 75019, Paris, France; Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France; CHNO des Quinze-Vingts, INSERM-DGOS CIC 1423, Paris, France
| | - K Bailey Freund
- LuEsther T. Mertz Retinal Research Center, Manhattan Eye, Ear, and Throat Hospital, New York, NY, USA; Vitreous Retina Macula Consultants of New York, New York, NY, USA; Department of Ophthalmology, New York University of Medicine, New York, NY, USA; Edward S. Harkness Eye Institute, Columbia University Medical Center, New York, NY, USA
| | - SriniVas R Sadda
- Doheny Image Reading Center, Doheny Eye Institute, Los Angeles, CA, 90033, USA; Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Gerard A Lutty
- Wilmer Ophthalmological Institute, Johns Hopkins Hospital, Baltimore, MD, 21287, USA
| | - Jay Chhablani
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA.
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7
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Rank EA, Sentosa R, Harper DJ, Salas M, Gaugutz A, Seyringer D, Nevlacsil S, Maese-Novo A, Eggeling M, Muellner P, Hainberger R, Sagmeister M, Kraft J, Leitgeb RA, Drexler W. Toward optical coherence tomography on a chip: in vivo three-dimensional human retinal imaging using photonic integrated circuit-based arrayed waveguide gratings. LIGHT, SCIENCE & APPLICATIONS 2021; 10:6. [PMID: 33402664 PMCID: PMC7785745 DOI: 10.1038/s41377-020-00450-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 11/14/2020] [Accepted: 12/03/2020] [Indexed: 05/19/2023]
Abstract
In this work, we present a significant step toward in vivo ophthalmic optical coherence tomography and angiography on a photonic integrated chip. The diffraction gratings used in spectral-domain optical coherence tomography can be replaced by photonic integrated circuits comprising an arrayed waveguide grating. Two arrayed waveguide grating designs with 256 channels were tested, which enabled the first chip-based optical coherence tomography and angiography in vivo three-dimensional human retinal measurements. Design 1 supports a bandwidth of 22 nm, with which a sensitivity of up to 91 dB (830 µW) and an axial resolution of 10.7 µm was measured. Design 2 supports a bandwidth of 48 nm, with which a sensitivity of 90 dB (480 µW) and an axial resolution of 6.5 µm was measured. The silicon nitride-based integrated optical waveguides were fabricated with a fully CMOS-compatible process, which allows their monolithic co-integration on top of an optoelectronic silicon chip. As a benchmark for chip-based optical coherence tomography, tomograms generated by a commercially available clinical spectral-domain optical coherence tomography system were compared to those acquired with on-chip gratings. The similarities in the tomograms demonstrate the significant clinical potential for further integration of optical coherence tomography on a chip system.
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Affiliation(s)
- Elisabet A Rank
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Waehringer Guertel 18-20/4 L, 1090, Vienna, Austria.
| | - Ryan Sentosa
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Waehringer Guertel 18-20/4 L, 1090, Vienna, Austria
| | - Danielle J Harper
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Waehringer Guertel 18-20/4 L, 1090, Vienna, Austria
| | - Matthias Salas
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Waehringer Guertel 18-20/4 L, 1090, Vienna, Austria
| | - Anna Gaugutz
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Waehringer Guertel 18-20/4 L, 1090, Vienna, Austria
| | - Dana Seyringer
- Research Centre for Microtechnology, Vorarlberg University of Applied Sciences, Hochschulstrasse 1, 6850, Dornbirn, Austria
| | - Stefan Nevlacsil
- AIT Austrian Institute of Technology GmbH, Gieffinggasse 4, 1210, Vienna, Austria
| | - Alejandro Maese-Novo
- AIT Austrian Institute of Technology GmbH, Gieffinggasse 4, 1210, Vienna, Austria
| | - Moritz Eggeling
- AIT Austrian Institute of Technology GmbH, Gieffinggasse 4, 1210, Vienna, Austria
| | - Paul Muellner
- AIT Austrian Institute of Technology GmbH, Gieffinggasse 4, 1210, Vienna, Austria
| | - Rainer Hainberger
- AIT Austrian Institute of Technology GmbH, Gieffinggasse 4, 1210, Vienna, Austria
| | | | - Jochen Kraft
- ams AG, Tobelbader Strasse 30, 8141, Premstaetten, Austria
| | - Rainer A Leitgeb
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Waehringer Guertel 18-20/4 L, 1090, Vienna, Austria
| | - Wolfgang Drexler
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Waehringer Guertel 18-20/4 L, 1090, Vienna, Austria
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8
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Shirazi MF, Brunner E, Laslandes M, Pollreisz A, Hitzenberger CK, Pircher M. Visualizing human photoreceptor and retinal pigment epithelium cell mosaics in a single volume scan over an extended field of view with adaptive optics optical coherence tomography. BIOMEDICAL OPTICS EXPRESS 2020; 11:4520-4535. [PMID: 32923061 PMCID: PMC7449740 DOI: 10.1364/boe.393906] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 07/13/2020] [Accepted: 07/17/2020] [Indexed: 05/18/2023]
Abstract
Using adaptive optics optical coherence tomography, human photoreceptors and retinal pigment epithelium (RPE) cells are typically visualized on a small field of view of ∼1° to 2°. In addition, volume averaging is required for visualizing the RPE cell mosaic. To increase the imaging area, we introduce a lens based spectral domain AO-OCT system that shows low aberrations within an extended imaging area of 4°×4° while maintaining a high (theoretical) transverse resolution (at >7 mm pupil diameter) in the order of 2 µm. A new concept for wavefront sensing is introduced that uses light mainly originating from the RPE layer and yields images of the RPE cell mosaic in a single volume acquisition. The capability of the instrument for in vivo imaging is demonstrated by visualizing various cell structures within the posterior retinal layers over an extended field of view.
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Affiliation(s)
- Muhammad Faizan Shirazi
- Center for Medical Physics and Biomedical
Engineering, Medical University of Vienna, Waehringer Guertel 18-20,
A-1090 Vienna, Austria
| | - Elisabeth Brunner
- Center for Medical Physics and Biomedical
Engineering, Medical University of Vienna, Waehringer Guertel 18-20,
A-1090 Vienna, Austria
| | - Marie Laslandes
- ALPAO 727 rue Aristide Bergès 38330
Montbonnot-Saint-Martin, France
| | - Andreas Pollreisz
- Department of Ophthalmology and Optometry,
Medical University of Vienna, Vienna, Waehringer Guertel 18-20, A-1090
Vienna, Austria
| | - Christoph K. Hitzenberger
- Center for Medical Physics and Biomedical
Engineering, Medical University of Vienna, Waehringer Guertel 18-20,
A-1090 Vienna, Austria
| | - Michael Pircher
- Center for Medical Physics and Biomedical
Engineering, Medical University of Vienna, Waehringer Guertel 18-20,
A-1090 Vienna, Austria
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9
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Gesperger J, Lichtenegger A, Roetzer T, Salas M, Eugui P, Harper DJ, Merkle CW, Augustin M, Kiesel B, Mercea PA, Widhalm G, Baumann B, Woehrer A. Improved Diagnostic Imaging of Brain Tumors by Multimodal Microscopy and Deep Learning. Cancers (Basel) 2020; 12:E1806. [PMID: 32640583 PMCID: PMC7408054 DOI: 10.3390/cancers12071806] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 06/26/2020] [Accepted: 07/01/2020] [Indexed: 11/16/2022] Open
Abstract
Fluorescence-guided surgery is a state-of-the-art approach for intraoperative imaging during neurosurgical removal of tumor tissue. While the visualization of high-grade gliomas is reliable, lower grade glioma often lack visible fluorescence signals. Here, we present a hybrid prototype combining visible light optical coherence microscopy (OCM) and high-resolution fluorescence imaging for assessment of brain tumor samples acquired by 5-aminolevulinic acid (5-ALA) fluorescence-guided surgery. OCM provides high-resolution information of the inherent tissue scattering and absorption properties of tissue. We here explore quantitative attenuation coefficients derived from volumetric OCM intensity data and quantitative high-resolution 5-ALA fluorescence as potential biomarkers for tissue malignancy including otherwise difficult-to-assess low-grade glioma. We validate our findings against the gold standard histology and use attenuation and fluorescence intensity measures to differentiate between tumor core, infiltrative zone and adjacent brain tissue. Using large field-of-view scans acquired by a near-infrared swept-source optical coherence tomography setup, we provide initial assessments of tumor heterogeneity. Finally, we use cross-sectional OCM images to train a convolutional neural network that discriminates tumor from non-tumor tissue with an accuracy of 97%. Collectively, the present hybrid approach offers potential to translate into an in vivo imaging setup for substantially improved intraoperative guidance of brain tumor surgeries.
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Affiliation(s)
- Johanna Gesperger
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, 1090 Vienna, Austria; (J.G.); (A.L.); (M.S.); (P.E.); (D.J.H.); (C.W.M.); (M.A.)
- Division of Neuropathology and Neurochemistry, Department of Neurology, Medical University of Vienna, 1090 Vienna, Austria; (T.R.); (A.W.)
| | - Antonia Lichtenegger
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, 1090 Vienna, Austria; (J.G.); (A.L.); (M.S.); (P.E.); (D.J.H.); (C.W.M.); (M.A.)
| | - Thomas Roetzer
- Division of Neuropathology and Neurochemistry, Department of Neurology, Medical University of Vienna, 1090 Vienna, Austria; (T.R.); (A.W.)
| | - Matthias Salas
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, 1090 Vienna, Austria; (J.G.); (A.L.); (M.S.); (P.E.); (D.J.H.); (C.W.M.); (M.A.)
| | - Pablo Eugui
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, 1090 Vienna, Austria; (J.G.); (A.L.); (M.S.); (P.E.); (D.J.H.); (C.W.M.); (M.A.)
| | - Danielle J. Harper
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, 1090 Vienna, Austria; (J.G.); (A.L.); (M.S.); (P.E.); (D.J.H.); (C.W.M.); (M.A.)
| | - Conrad W. Merkle
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, 1090 Vienna, Austria; (J.G.); (A.L.); (M.S.); (P.E.); (D.J.H.); (C.W.M.); (M.A.)
| | - Marco Augustin
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, 1090 Vienna, Austria; (J.G.); (A.L.); (M.S.); (P.E.); (D.J.H.); (C.W.M.); (M.A.)
| | - Barbara Kiesel
- Department of Neurosurgery, Medical University of Vienna, 1090 Vienna, Austria; (B.K.); (P.A.M.)
| | - Petra A. Mercea
- Department of Neurosurgery, Medical University of Vienna, 1090 Vienna, Austria; (B.K.); (P.A.M.)
| | - Georg Widhalm
- Department of Neurosurgery, Medical University of Vienna, 1090 Vienna, Austria; (B.K.); (P.A.M.)
| | - Bernhard Baumann
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, 1090 Vienna, Austria; (J.G.); (A.L.); (M.S.); (P.E.); (D.J.H.); (C.W.M.); (M.A.)
| | - Adelheid Woehrer
- Division of Neuropathology and Neurochemistry, Department of Neurology, Medical University of Vienna, 1090 Vienna, Austria; (T.R.); (A.W.)
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10
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Lichtenegger A, Gesperger J, Niederleithner M, Ginner L, Woehrer A, Drexler W, Baumann B, Leitgeb RA, Salas M. Ex-vivo Alzheimer's disease brain tissue investigation: a multiscale approach using 1060-nm swept source optical coherence tomography for a direct correlation to histology. NEUROPHOTONICS 2020; 7:035004. [PMID: 32855993 PMCID: PMC7441220 DOI: 10.1117/1.nph.7.3.035004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 08/04/2020] [Indexed: 06/11/2023]
Abstract
Significance: Amyloid-beta ( A - β ) plaques are pathological protein deposits formed in the brain of Alzheimer's disease (AD) patients upon disease progression. Further research is needed to elucidate the complex underlying mechanisms involved in their formation using label-free, tissue preserving, and volumetric techniques. Aim: The aim is to achieve a one-to-one correlation of optical coherence tomography (OCT) data to histological micrographs of brain tissue using 1060-nm swept source OCT. Approach: A - β plaques were investigated in ex-vivo AD brain tissue using OCT with the capability of switching between two magnifications. For the exact correlation to histology, a 3D-printed tool was designed to generate samples with parallel flat surfaces. Large field-of-view (FoV) and sequentially high-resolution volumes at different locations were acquired. The large FoV served to align the OCT to histology images; the high-resolution images were used to visualize fine details. Results: The instrument and the presented method enabled an accurate correlation of histological micrographs with OCT data. A - β plaques were identified as hyperscattering features in both FoV OCT modalities. The plaques identified in volumetric OCT data were in good agreement with immunohistochemically derived micrographs. Conclusion: OCT combined with the 3D-printed tool is a promising approach for label-free, nondestructive, volumetric, and fast tissue analysis.
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Affiliation(s)
- Antonia Lichtenegger
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
| | - Johanna Gesperger
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
- Medical University of Vienna, Division of Neuropathology and Neurochemistry, Department of Neurology, Vienna, Austria
| | - Michael Niederleithner
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
| | - Laurin Ginner
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
- AIT Austrian Institute of Technology GmbH, Vienna, Austria
| | - Adelheid Woehrer
- Medical University of Vienna, Division of Neuropathology and Neurochemistry, Department of Neurology, Vienna, Austria
| | - Wolfgang Drexler
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
| | - Bernhard Baumann
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
| | - Rainer A. Leitgeb
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
- Medical University of Vienna, Christian Doppler Laboratory for Innovative Optical Imaging and its Translation to Medicine, Vienna, Austria
| | - Matthias Salas
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
- Medical University of Vienna, Division of Neuropathology and Neurochemistry, Department of Neurology, Vienna, Austria
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11
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Tey KY, Teo K, Tan ACS, Devarajan K, Tan B, Tan J, Schmetterer L, Ang M. Optical coherence tomography angiography in diabetic retinopathy: a review of current applications. EYE AND VISION 2019; 6:37. [PMID: 31832448 PMCID: PMC6859616 DOI: 10.1186/s40662-019-0160-3] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Accepted: 10/14/2019] [Indexed: 01/09/2023]
Abstract
Background Diabetic retinopathy (DR) is a leading cause of vision loss in adults. Currently, the standard imaging technique to monitor and prognosticate DR and diabetic maculopathy is dye-based angiography. With the introduction of optical coherence tomography angiography (OCTA), it may serve as a potential rapid, non-invasive imaging modality as an adjunct. Main text Recent studies on the role of OCTA in DR include the use of vascular parameters e.g., vessel density, intercapillary spacing, vessel diameter index, length of vessels based on skeletonised OCTA, the total length of vessels, vascular architecture and area of the foveal avascular zone. These quantitative measures may be able to detect changes with the severity and progress of DR for clinical research. OCTA may also serve as a non-invasive imaging method to detect diabetic macula ischemia, which may help predict visual prognosis. However, there are many limitations of OCTA in DR, such as difficulty in segmentation between superficial and deep capillary plexus; and its use in diabetic macula edema where the presence of cystic spaces may affect image results. Future applications of OCTA in the anterior segment include detection of anterior segment ischemia and iris neovascularisation associated with proliferative DR and risk of neovascular glaucoma. Conclusion OCTA may potentially serve as a useful non-invasive imaging tool in the diagnosis and monitoring of diabetic retinopathy and maculopathy in the future. Future studies may demonstrate how quantitative OCTA measures may have a role in detecting early retinal changes in patients with diabetes.
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Affiliation(s)
- Kai Yuan Tey
- Hobart Clinical School, Level 3, 43 Collins Street, Hobart, TAS 7000 Australia
| | - Kelvin Teo
- 2Singapore National Eye Centre, 11 Third Hospital Ave, Singapore, 168751 Singapore
| | - Anna C S Tan
- 2Singapore National Eye Centre, 11 Third Hospital Ave, Singapore, 168751 Singapore
| | - Kavya Devarajan
- 3Singapore Eye Research Institute, 20 College Road Discovery Tower, Level 6 The Academia, Singapore, 169856 Singapore
| | - Bingyao Tan
- 3Singapore Eye Research Institute, 20 College Road Discovery Tower, Level 6 The Academia, Singapore, 169856 Singapore
| | - Jacqueline Tan
- 3Singapore Eye Research Institute, 20 College Road Discovery Tower, Level 6 The Academia, Singapore, 169856 Singapore
| | - Leopold Schmetterer
- 3Singapore Eye Research Institute, 20 College Road Discovery Tower, Level 6 The Academia, Singapore, 169856 Singapore
| | - Marcus Ang
- 4Singapore National Eye Centre, 11 Third Hospital Ave, Singapore 168751; Duke-NUS Medical School, 8 College Rd, Singapore, 169857 Singapore
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12
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Gräfe MGO, Nadiarnykh O, De Boer JF. Optical coherence tomography velocimetry based on decorrelation estimation of phasor pair ratios (DEPPAIR). BIOMEDICAL OPTICS EXPRESS 2019; 10:5470-5485. [PMID: 31799025 PMCID: PMC6865093 DOI: 10.1364/boe.10.005470] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 09/17/2019] [Accepted: 09/20/2019] [Indexed: 05/13/2023]
Abstract
Quantitative velocity estimations in optical coherence tomography requires the estimation of the axial and lateral flow components. Optical coherence tomography measures the depth resolved complex field reflected from a sample. While the axial velocity component can be determined from the Doppler shift or phase shift between a pair of consecutive measurements at the same location, the estimation of the lateral component for in vivo applications is still challenging. One approach to determine lateral velocity is multiple simultaneous measurements at different angles. In another approach the lateral component can be retrieved through repeated measurements at (nearly) the same location by an analysis of the decorrelation over time. In this paper we follow the latter approach. We describe a model for the complex field changes between consecutive measurements and use it to predict the uncertainties for amplitude-based, phase-based and complex algorithms. The uncertainty of the flow estimations follows from a statistical analysis and is determined by the number of available measurements and the applied analysis method. The model is verified in phantom measurements and the dynamic range of velocity estimations is investigated. We demonstrate that phase-based and complex (phasor) based lateral flow estimation methods are superior to amplitude-based algorithms.
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13
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Slepneva S, Kovalev A, Rebrova N, Grigorenko K, Viktorov E, Huyet G. Coherence transfer in an akinetic swept source OCT laser with optical feedback. OPTICS LETTERS 2019; 44:5161-5164. [PMID: 31674956 DOI: 10.1364/ol.44.005161] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 09/23/2019] [Indexed: 06/10/2023]
Abstract
We theoretically investigate the influence of optical feedback onto the dynamics of a semiconductor swept source laser. In particular, we show that optical feedback can be used to lock the phase of the successive lasing modes of a multi-section semiconductor laser commonly used for optical coherence tomography (OCT) applications. We also identify two different regimes called sliding frequency self-mixing and sliding frequency mode locking. The second regime demonstrates sub-nanosecond sliding frequency pulses for nonlinear optics applications.
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14
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Review on Retrospective Procedures to Correct Retinal Motion Artefacts in OCT Imaging. APPLIED SCIENCES-BASEL 2019. [DOI: 10.3390/app9132700] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Motion artefacts from involuntary changes in eye fixation remain a major imaging issue in optical coherence tomography (OCT). This paper reviews the state-of-the-art of retrospective procedures to correct retinal motion and axial eye motion artefacts in OCT imaging. Following an overview of motion induced artefacts and correction strategies, a chronological survey of retrospective approaches since the introduction of OCT until the current days is presented. Pre-processing, registration, and validation techniques are described. The review finishes by discussing the limitations of the current techniques and the challenges to be tackled in future developments.
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15
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Leitgeb RA. En face optical coherence tomography: a technology review [Invited]. BIOMEDICAL OPTICS EXPRESS 2019; 10:2177-2201. [PMID: 31143489 PMCID: PMC6524600 DOI: 10.1364/boe.10.002177] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 03/01/2019] [Accepted: 03/05/2019] [Indexed: 05/20/2023]
Abstract
A review on the technological development of en face optical coherence tomography (OCT) and optical coherence microscopy (OCM) is provided. The terminology originally referred to time domain OCT, where the preferential scanning was performed in the en face plane. Potentially the fastest realization of en face image recording is full-field OCT, where the full en face plane is illuminated and recorded simultaneously. The term has nowadays been adopted for high-speed Fourier domain approaches, where the en face image is reconstructed from full 3D volumes either by direct slicing or through axial projection in post processing. The success of modern en face OCT lies in its immediate and easy image interpretation, which is in particular of advantage for OCM or OCT angiography. Applications of en face OCT with a focus on ophthalmology are presented. The review concludes by outlining exciting technological prospects of en face OCT based both on time as well as on Fourier domain OCT.
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Affiliation(s)
- R A Leitgeb
- Center for Medical Physics and Biomedical Engineering, Medical University Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria
- Christian Doppler Laboratory for Innovative Optical Imaging and its Translation to Medicine, Medical University Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria
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16
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Lee HD, Kim GH, Shin JG, Lee B, Kim CS, Eom TJ. Akinetic swept-source optical coherence tomography based on a pulse-modulated active mode locking fiber laser for human retinal imaging. Sci Rep 2018; 8:17660. [PMID: 30518926 PMCID: PMC6281618 DOI: 10.1038/s41598-018-36252-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 11/15/2018] [Indexed: 01/09/2023] Open
Abstract
Optical coherence tomography (OCT) is a noninvasive imaging modality that can provide high-resolution, cross-sectional images of tissues. Especially in retinal imaging, OCT has become one of the most valuable imaging tools for diagnosing eye diseases. Considering the scattering and absorption properties of the eye, the 1000-nm OCT system is preferred for retinal imaging. In this study, we describe the use of an akinetic swept-source OCT system based on a pulse-modulated active mode locking (AML) fiber laser at a 1080-nm wavelength for in-vivo human retinal imaging. The akinetic AML wavelength-swept fiber laser was constructed with polarization-maintaining fiber that has an average linewidth of 0.625 nm, a spectral bandwidth of 81.15 nm, and duty ratio of 90% without the buffering method. We successfully obtained in-vivo human retinal images using the proposed OCT system without the additional k-clock and the frequency shifter that provides a wide field of view of 43.1°. The main retina layers, such as the retinal pigment epithelium, can be distinguished from the OCT image with an axial resolution of 6.3 μm with this OCT system.
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Affiliation(s)
- Hwi Don Lee
- Advanced Photonics Research Institute, Gwangju Institute of Science and Technology, Gwangju, 61005, South Korea
| | - Gyeong Hun Kim
- Department of Cogno-Mechatronics Engineering, Pusan National University, Busan, 46241, South Korea
| | - Jun Geun Shin
- Advanced Photonics Research Institute, Gwangju Institute of Science and Technology, Gwangju, 61005, South Korea
| | - Boram Lee
- Department of ophthalmology, Korea University college of medicine, Seoul, 02841, South Korea
| | - Chang-Seok Kim
- Department of Cogno-Mechatronics Engineering, Pusan National University, Busan, 46241, South Korea.
| | - Tae Joong Eom
- Advanced Photonics Research Institute, Gwangju Institute of Science and Technology, Gwangju, 61005, South Korea.
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17
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Heisler M, Ju MJ, Bhalla M, Schuck N, Athwal A, Navajas EV, Beg MF, Sarunic MV. Automated identification of cone photoreceptors in adaptive optics optical coherence tomography images using transfer learning. BIOMEDICAL OPTICS EXPRESS 2018; 9:5353-5367. [PMID: 30460133 PMCID: PMC6238943 DOI: 10.1364/boe.9.005353] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 10/01/2018] [Accepted: 10/02/2018] [Indexed: 05/11/2023]
Abstract
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 different AO-OCT images acquired from five normal subjects. Voronoi analysis confirmed the general hexagonal-packing structure of the cone mosaic as well as the general cone density variability across portions of the retina. The consistency of our measurements demonstrates the high reliability and practical utility of having an automated solution to this problem.
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Affiliation(s)
- Morgan Heisler
- Simon Fraser University, Department of Engineering Science, 8888 University Drive, Burnaby, BC, V5A 1S6,
Canada
| | - Myeong Jin Ju
- Simon Fraser University, Department of Engineering Science, 8888 University Drive, Burnaby, BC, V5A 1S6,
Canada
| | - Mahadev Bhalla
- University of British Columbia, Faculty of Medicine, 317 - 2194 Health Sciences Mall, Vancouver, BC, V6T 1Z3,
Canada
| | - Nathan Schuck
- University of British Columbia, Faculty of Medicine, 317 - 2194 Health Sciences Mall, Vancouver, BC, V6T 1Z3,
Canada
| | - Arman Athwal
- Simon Fraser University, Department of Engineering Science, 8888 University Drive, Burnaby, BC, V5A 1S6,
Canada
| | - Eduardo V. Navajas
- University of British Columbia, Department of Ophthalmology & Vision Science, 2550 Willow Street, Vancouver, BC, V5Z 3N9,
Canada
| | - Mirza Faisal Beg
- Simon Fraser University, Department of Engineering Science, 8888 University Drive, Burnaby, BC, V5A 1S6,
Canada
| | - Marinko V. Sarunic
- Simon Fraser University, Department of Engineering Science, 8888 University Drive, Burnaby, BC, V5A 1S6,
Canada
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