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      A head mounted device stimulator for optogenetic retinal prosthesis

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          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          Objective. Our main objective is to demonstrate that compact high radiance gallium nitride displays can be used with conventional virtual reality optics to stimulate an optogenetic retina. Hence, we aim to introduce a non-invasive approach to restore vision for people with conditions such as retinitis pigmentosa where there is a remaining viable communication link between the retina and the visual cortex. Approach. We design and implement the headset using a high-density µLED matrix, Raspberry Pi, microcontroller from NXP and virtual reality lens. Then, a test platform is developed to evaluate the performance of the headset and the optical system. Furthermore, image simplification algorithms are used to simplify the scene to be sent to the retina. Moreover, in vivo evaluation of the genetically modified retina response at different light intensity is discussed to prove the reliability of the proposed system . Main results. We demonstrate that in keeping with regulatory guidance, the headset displays need to limit their luminance to 90 kcd m −2. We demonstrate an optical system with 5.75% efficiency which allows for 0.16 mW mm −2 irradiance on the retina within the regulatory guidance, but which is capable of an average peak irradiance of 1.35 mW mm −2. As this is lower than the commonly accepted threshold for channelrhodopsin-2, we demonstrate efficacy through an optical model of an eye onto a biological retina. Significance. We demonstrate a fully functional 8100-pixel headset system including software/hardware which can operate on a standard consumer battery for periods exceeding a 24 h recharge cycle. The headset is capable of delivering enough light to stimulate the genetically modified retina cells and also keeping the amount of light below the regulation threshold for safety.

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          Most cited references 54

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          The Laplacian Pyramid as a Compact Image Code

           J P Burt,  M Adelson (1983)
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            Channelrhodopsin-2, a directly light-gated cation-selective membrane channel.

            Microbial-type rhodopsins are found in archaea, prokaryotes, and eukaryotes. Some of them represent membrane ion transport proteins such as bacteriorhodopsin, a light-driven proton pump, or channelrhodopsin-1 (ChR1), a recently identified light-gated proton channel from the green alga Chlamydomonas reinhardtii. ChR1 and ChR2, a related microbial-type rhodopsin from C. reinhardtii, were shown to be involved in generation of photocurrents of this green alga. We demonstrate by functional expression, both in oocytes of Xenopus laevis and mammalian cells, that ChR2 is a directly light-switched cation-selective ion channel. This channel opens rapidly after absorption of a photon to generate a large permeability for monovalent and divalent cations. ChR2 desensitizes in continuous light to a smaller steady-state conductance. Recovery from desensitization is accelerated by extracellular H+ and negative membrane potential, whereas closing of the ChR2 ion channel is decelerated by intracellular H+. ChR2 is expressed mainly in C. reinhardtii under low-light conditions, suggesting involvement in photoreception in dark-adapted cells. The predicted seven-transmembrane alpha helices of ChR2 are characteristic for G protein-coupled receptors but reflect a different motif for a cation-selective ion channel. Finally, we demonstrate that ChR2 may be used to depolarize small or large cells, simply by illumination.
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              Magnitude, temporal trends, and projections of the global prevalence of blindness and distance and near vision impairment: a systematic review and meta-analysis.

              Global and regional prevalence estimates for blindness and vision impairment are important for the development of public health policies. We aimed to provide global estimates, trends, and projections of global blindness and vision impairment.
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                Author and article information

                Journal
                J Neural Eng
                J Neural Eng
                jne
                JNEIEZ
                Journal of Neural Engineering
                IOP Publishing
                1741-2560
                1741-2552
                December 2018
                9 October 2018
                : 15
                : 6
                Affiliations
                [1 ]School of Engineering, Newcastle University , Newcastle upon Tyne, NE1 7RU, United Kingdom
                [2 ]Institute of Neuroscience, Newcastle University , Newcastle upon Tyne, NE1 7RU, United Kingdom
                [3 ]Tyndall Institute, University of Cork , Cork, Republic of Ireland
                [4 ]C4 Sightcare Ltd, Northumberland House , Newcastle upon Tyne, NE1 8ER, United Kingdom
                [5 ]Department of Biomedical Engineering, Helwan University , Helwan, Egypt
                [6 ]Blackett Laboratory, Department Physics, Imperial College , London SW7 2AZ, United Kingdom
                patrick.degenaar@ 123456newcastle.ac.uk
                Article
                jneaadd55 aadd55 JNE-102313.R2
                10.1088/1741-2552/aadd55
                6372131
                30156188
                © 2018 IOP Publishing Ltd

                Original content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.

                Page count
                Pages: 15
                Funding
                Funded by: Wellcome Trust https://doi.org/10.13039/100004440
                Award ID: 102037/Z/13/Z
                Funded by: Engineering and Physical Sciences Research Council https://doi.org/10.13039/501100000266
                Award ID: NS/A000026/1
                Funded by: European Commission https://doi.org/10.13039/501100000780
                Award ID: 249867
                Funded by: British Council https://doi.org/10.13039/501100000308
                Award ID: 216344044
                Categories
                Paper
                The Eye and the Chip 2017
                Custom metadata
                1741-2552/18/065002+15$33.00
                Printed in the UK
                yes

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