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Schulz A, Knoll T, Jaeger T, Le Harzic R, Stracke F, Wien SL, Olsommer Y, Meiser I, Wagner S, Rammensee M, Kurz O, Klesy S, Sermeus L, Julich-Haertel H, Schweitzer Y, Januschowski K, Velten T, Szurman P. Photovoltaic, wireless wide-field epiretinal prosthesis to treat retinitis pigmentosa. Acta Ophthalmol 2024. [PMID: 38923194 DOI: 10.1111/aos.16733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 06/11/2024] [Indexed: 06/28/2024]
Abstract
PURPOSE To develop and evaluate a photovoltaic, wireless wide-field epiretinal prosthesis for the treatment of retinitis pigmentosa. METHODS A mosaic array of thinned silicon-based photodiodes with integrated thin-film stimulation electrodes was fabricated with a flexible polyimide substrate film to form a film-based miniaturized electronic system with wireless optical power and signal transmission and integrated electrostimulation. Manufactured implants were characterized with respect to their optoelectronic performance and biocompatibility following DIN EN ISO 10993. RESULTS A 14 mm diameter prosthesis containing 1276 pixels with a maximum sensitivity at a near infrared wavelength of 905 nm and maximized stimulation current density 30-50 μm below the electrodes was developed for direct activation of retinal ganglion cells during epiretinal stimulation. Fabricated prostheses demonstrated mucosal tolerance and the preservation of both metabolic activity, proliferation and membrane integrity of human fibroblasts as well as the retinal functions of bovine retinas. Illumination of the prosthesis, which was placed epiretinally on an isolated perfused bovine retina, with infrared light resulted in electrophysiological recordings reminiscent of an a-wave (hyperpolarization) and b-wave (depolarization). CONCLUSIONS A photovoltaic, wireless wide-field epiretinal prosthesis for the treatment of retinitis pigmentosa using near infrared light for signal transmission was designed, manufactured and its biocompatibility and functionality demonstrated in vitro and ex vivo.
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Affiliation(s)
- André Schulz
- Eye Clinic Sulzbach, Knappschaft Hospital Saar, Sulzbach, Germany
- Klaus Heimann Eye Research Institute, Sulzbach, Germany
| | - Thorsten Knoll
- Fraunhofer Institute for Biomedical Engineering IBMT, Sulzbach, Germany
| | | | - Ronan Le Harzic
- Fraunhofer Institute for Biomedical Engineering IBMT, Sulzbach, Germany
| | - Frank Stracke
- Fraunhofer Institute for Biomedical Engineering IBMT, Sulzbach, Germany
| | - Sascha L Wien
- Fraunhofer Institute for Biomedical Engineering IBMT, Sulzbach, Germany
| | - Yves Olsommer
- Fraunhofer Institute for Biomedical Engineering IBMT, Sulzbach, Germany
| | - Ina Meiser
- Fraunhofer Institute for Biomedical Engineering IBMT, Sulzbach, Germany
| | - Sylvia Wagner
- Fraunhofer Institute for Biomedical Engineering IBMT, Sulzbach, Germany
| | | | | | | | - Loic Sermeus
- Eye Clinic Sulzbach, Knappschaft Hospital Saar, Sulzbach, Germany
| | - Henrike Julich-Haertel
- Eye Clinic Sulzbach, Knappschaft Hospital Saar, Sulzbach, Germany
- Klaus Heimann Eye Research Institute, Sulzbach, Germany
| | | | - Kai Januschowski
- Eye Clinic Sulzbach, Knappschaft Hospital Saar, Sulzbach, Germany
- Klaus Heimann Eye Research Institute, Sulzbach, Germany
| | - Thomas Velten
- Fraunhofer Institute for Biomedical Engineering IBMT, Sulzbach, Germany
| | - Peter Szurman
- Eye Clinic Sulzbach, Knappschaft Hospital Saar, Sulzbach, Germany
- Klaus Heimann Eye Research Institute, Sulzbach, Germany
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2
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Sadeghi R, Kartha A, Barry MP, Gibson P, Caspi A, Roy A, Geruschat DR, Dagnelie G. Benefits of thermal and distance-filtered imaging for wayfinding with prosthetic vision. Sci Rep 2024; 14:1313. [PMID: 38225344 PMCID: PMC10789760 DOI: 10.1038/s41598-024-51798-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Accepted: 01/09/2024] [Indexed: 01/17/2024] Open
Abstract
Visual prostheses such as the Argus II provide partial vision for individuals with limited or no light perception. However, their effectiveness in daily life situations is limited by scene complexity and variability. We investigated whether additional image processing techniques could improve mobility performance in everyday indoor environments. A mobile system connected to the Argus II provided thermal or distance-filtered video stimulation. Four participants used the thermal camera to locate a person and the distance filter to navigate a hallway with obstacles. The thermal camera allowed for finding a target person in 99% of trials, while unfiltered video led to confusion with other objects and a success rate of only 55% ([Formula: see text]). Similarly, the distance filter enabled participants to detect and avoid 88% of obstacles by removing background clutter, whereas unfiltered video resulted in a detection rate of only 10% ([Formula: see text]). For any given elapsed time, the success rate with filtered video was higher than with unfiltered video. After 90 s, participants' success rate reached above 50% with filtered video and 24% and 3% with normal camera in the first and second tasks, respectively. Despite individual variations, all participants showed significant improvement when using the thermal and distance filters compared to unfiltered video. Adding a thermal and distance filter to a visual prosthesis system can enhance the performance of mobility activities by removing clutter in the background, showing people and warm objects with the thermal camera, or nearby obstacles with the distance filter.
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Affiliation(s)
- Roksana Sadeghi
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, MD, USA.
- Herbert Wertheim School of Optometry and Vision Science, University of California, Berkeley, CA, USA.
| | - Arathy Kartha
- Department of Biological and Vision Sciences, State University of New York College of Optometry, New York, NY, USA
- Department of Ophthalmology, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Michael P Barry
- Department of Ophthalmology, Johns Hopkins School of Medicine, Baltimore, MD, USA
- Pritzker Institute for Biomedical Science and Engineering, Illinois Institute of Technology, Chicago, IL, USA
| | - Paul Gibson
- Advanced Medical Electronics Corporation, Maple Grove, MN, USA
| | - Avi Caspi
- Jerusalem College of Technology, Jerusalem, Israel
| | | | - Duane R Geruschat
- Department of Ophthalmology, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Gislin Dagnelie
- Department of Ophthalmology, Johns Hopkins School of Medicine, Baltimore, MD, USA
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Kwan WC, Brunton EK, Begeng JM, Richardson RT, Ibbotson MR, Tong W. Timing is Everything: Stochastic Optogenetic Stimulation Reduces Adaptation in Retinal Ganglion Cells. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2023; 2023:1-4. [PMID: 38083106 DOI: 10.1109/embc40787.2023.10340849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2023]
Abstract
Optogenetics gives us unprecedented power to investigate brain connectivity. The ability to activate neural circuits with single cell resolution and its ease of application has provided a wealth of knowledge in brain function. More recently, optogenetics has shown tremendous utility in prosthetics applications, including vision restoration for patients with retinitis pigmentosa. One of the disadvantages of optogenetics, however, is its poor temporal bandwidth, i.e. the cell's inability to fire at a rate that matches the optical stimulation rate at high frequencies (>30 Hz). This research proposes a new strategy to overcome the temporal limits of optogenetic stimulation. Using whole-cell current clamp recordings in mouse retinal ganglion cells expressing channelrhodopsin-2 (H134R variant), we observed that randomizing inter-pulse intervals can significantly increase a retinal ganglion cell's temporal response to high frequency stimulation.Clinical Relevance- A significant disadvantage of optogenetic stimulation is its poor temporal dynamics which prohibit its widespread use in retinal prosthetics. We have shown that randomizing the interval between stimulation pulses reduces adaptation in retinal ganglion cells. This stimulation strategy may contribute to new levels of functional restoration in therapeutics which incorporate optogenetics.
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Copper–Ruthenium Composite as Perspective Material for Bioelectrodes: Laser-Assisted Synthesis, Biocompatibility Study, and an Impedance-Based Cellular Biosensor as Proof of Concept. BIOSENSORS 2022; 12:bios12070527. [PMID: 35884330 PMCID: PMC9313201 DOI: 10.3390/bios12070527] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 07/03/2022] [Accepted: 07/06/2022] [Indexed: 11/17/2022]
Abstract
Copper is an inexpensive material that has found wide application in electronics due to its remarkable electric properties. However, the high toxicity of both copper and copper oxide imposes restrictions on the application of this metal as a material for bioelectronics. One way to increase the biocompatibility of pure copper while keeping its remarkable properties is to use copper-based composites. In the present study, we explored a new copper–ruthenium composite as a potential biocompatible material for bioelectrodes. Sample electrodes were obtained by subsequent laser deposition of copper and ruthenium on glass plates from a solution containing salts of these metals. The fabricated Cu–Ru electrodes exhibit high effective area and their impedance properties can be described by simple R-CPE equivalent circuits that make them perspective for sensing applications. Finally, we designed a simple impedance cell-based biosensor using this material that allows us to distinguish between dead and alive HeLa cells.
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5
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Italiano ML, Guo T, Lovell NH, Tsai D. Improving the spatial resolution of artificial vision using midget retinal ganglion cell populations modelled at the human fovea. J Neural Eng 2022; 19. [PMID: 35609556 DOI: 10.1088/1741-2552/ac72c2] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Accepted: 05/24/2022] [Indexed: 11/11/2022]
Abstract
OBJECTIVE Retinal prostheses seek to create artificial vision by stimulating surviving retinal neurons of patients with profound vision impairment. Notwithstanding tremendous research efforts, the performance of all implants tested to date has remained rudimentary, incapable of overcoming the threshold for legal blindness. To maximize the perceptual efficacy of retinal prostheses, a device must be capable of controlling retinal neurons with greater spatiotemporal precision. Most studies of retinal stimulation were derived from either non-primate species or the peripheral primate retina. We investigated if artificial stimulation could leverage the high spatial resolution afforded by the neural substrates at the primate fovea and surrounding regions to achieve improved percept qualities. APPROACH We began by developing a new computational model capable of generating anatomically accurate retinal ganglion cell (RGC) populations within the human central retina. Next, multiple RGC populations across the central retina were stimulated in-silico to compare clinical and recently proposed neurostimulation configurations based on their ability to improve perceptual efficacy and reduce activation thresholds. MAIN RESULTS Our model uniquely upholds eccentricity-dependent characteristics such as RGC density and dendritic field diameter, whilst incorporating anatomically accurate features such as axon projection and three-dimensional RGC layering, features often forgone in favor of reduced computational complexity. Following epiretinal stimulation, the RGCs in our model produced response patterns in shapes akin to the complex percepts reported in clinical trials. Our results also demonstrated that even within the neuron-dense central retina, epiretinal stimulation using a multi-return hexapolar electrode arrangement could reliably achieve spatially focused RGC activation and could achieve single-cell excitation in 74% of all tested locations. SIGNIFICANCE This study establishes an anatomically accurate three-dimensional model of the human central retina and demonstrates the potential for an epiretinal hexapolar configuration to achieve consistent, spatially confined retinal responses, even within the neuron-dense foveal region. Our results promote the prospect and optimization of higher spatial resolution in future epiretinal implants.
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Affiliation(s)
- Michael Lewis Italiano
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, Sydney, New South Wales, 2052, AUSTRALIA
| | - Tianruo Guo
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, Sydney, New South Wales, 2052, AUSTRALIA
| | - Nigel H Lovell
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, Sydney, New South Wales, 2052, AUSTRALIA
| | - David Tsai
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, Sydney, New South Wales, 2052, AUSTRALIA
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Kravchenko SV, Sakhnov SN, Myasnikova VV. Modern concepts of bionic vision. Vestn Oftalmol 2022; 138:95-101. [PMID: 35801887 DOI: 10.17116/oftalma202213803195] [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] [Indexed: 06/15/2023]
Abstract
Loss of vision is a pressing medical and social problem leading to profound disability, loss of ability to work, serious alterations in the psycho-emotional state, and a decline of the quality of life. When conservative or surgical treatment can not help restore vision, the use of visual prosthesis - bionic eye - can be an effective solution. This review covers the main modern approaches to the development of visual prosthetic systems. Analysis of publications revealed that there are several main approaches to visual prosthesis differing primarily by the anatomical structure targeted for stimulation in order to activate visual sensations. The most significant among them are retinal prostheses, optic nerve stimulation, and cortical visual prostheses. Currently, retinal prostheses such as ARGUS II demonstrate the most successful results, since the stimulation of the surviving neural structures of the retina is a relatively easy task, but their field of application is limited to diseases associated with pathological changes in photoreceptors. The development of cortical visual prostheses is more difficult, but in the future they may allow using more stimulation channels to obtain a more detailed visual perception. In addition, cortical visual prostheses are universal, as they do not require preservation of any structures of the visual organ, only the primary visual cortex.
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Affiliation(s)
- S V Kravchenko
- Krasnodar branch of S.N. Fedorov National Medical Research Center «MNTK «Eye Microsurgery», Krasnodar, Russia
| | - S N Sakhnov
- Krasnodar branch of S.N. Fedorov National Medical Research Center «MNTK «Eye Microsurgery», Krasnodar, Russia
- Kuban State Medical University, Krasnodar, Russia
| | - V V Myasnikova
- Krasnodar branch of S.N. Fedorov National Medical Research Center «MNTK «Eye Microsurgery», Krasnodar, Russia
- Kuban State Medical University, Krasnodar, Russia
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7
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Hallum LE, Dakin SC. Retinal Implantation of Electronic Vision Prostheses to Treat Retinitis Pigmentosa: A Systematic Review. Transl Vis Sci Technol 2021; 10:8. [PMID: 34383874 PMCID: PMC8362638 DOI: 10.1167/tvst.10.10.8] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Purpose Retinitis pigmentosa (RP) is a hereditary disease causing photoreceptor degeneration and permanent vision loss. Retinal implantation of a stimulating electrode array is a new treatment for RP, but quantification of its efficacy is the subject of ongoing work. This review evaluates vision-related outcomes resulting from retinal implantation in participants with RP. Methods We searched MEDLINE and Embase for journal articles published since January 1, 2015. We selected articles describing studies of implanted participants that reported the postimplantation measurement of vision. We extracted study information including design, participants’ residual vision, comparators, and assessed outcomes. To assess the risk of bias, we used signaling questions and a target trial. Results Our search returned 425 abstracts. We reviewed the full text of 34 articles. We judged all studies to be at high risk of bias owing to the study design or experimental conduct. Regarding design, studies lacked the measures that typical clinical trials take to protect against bias (e.g., control groups and masking). Regarding experimental conduct, outcome measures were rarely comparable before and after implantation, and psychophysical methods were prone to bias (subjective, not forced choice, methods). The most common comparison found was between postimplantation visual function with the device powered off versus on. This comparison is at high risk of bias. Conclusions There is a need for high-quality evidence of efficacy of retinal implantation to treat RP. Translational Relevance For patients and clinicians to make informed choices about RP treatment, visual function restored by retinal implantation must be properly quantified and reported.
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Affiliation(s)
- Luke E Hallum
- Department of Mechanical Engineering, University of Auckland, Auckland, New Zealand
| | - Steven C Dakin
- School of Optometry and Vision Science, University of Auckland, Auckland, New Zealand
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8
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Karapanos L, Abbott CJ, Ayton LN, Kolic M, McGuinness MB, Baglin EK, Titchener SA, Kvansakul J, Johnson D, Kentler WG, Barnes N, Nayagam DAX, Allen PJ, Petoe MA. Functional Vision in the Real-World Environment With a Second-Generation (44-Channel) Suprachoroidal Retinal Prosthesis. Transl Vis Sci Technol 2021; 10:7. [PMID: 34383875 PMCID: PMC8362639 DOI: 10.1167/tvst.10.10.7] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Accepted: 06/09/2021] [Indexed: 11/24/2022] Open
Abstract
Purpose In a clinical trial (NCT03406416) of a second-generation (44-channel) suprachoroidal retinal prosthesis implanted in subjects with late-stage retinitis pigmentosa (RP), we assessed performance in real-world functional visual tasks and emotional well-being. Methods The Functional Low-Vision Observer Rated Assessment (FLORA) and Impact of Vision Impairment-Very Low Vision (IVI-VLV) instruments were administered to four subjects before implantation and after device fitting. The FLORA contains 13 self-reported and 35 observer-reported items ranked for ease of conducting task (impossible-easy, central tendency given as mode). The IVI-VLV instrument quantified the impact of low vision on daily activities and emotional well-being. Results Three subjects completed the FLORA for two years after device fitting; the fourth subject ceased participation in the FLORA after fitting for reasons unrelated to the device. For all subjects at each post-fitting visit, the mode ease of task with device ON was better or equal to device OFF. Ease of task improved over the first six months with device ON, then remained stable. Subjects reported improvements in mobility, functional vision, and quality of life with device ON. The IVI-VLV suggested self-assessed vision-related quality of life was not impacted by device implantation or usage. Conclusions Subjects demonstrated sustained improved ease of task scores with device ON compared to OFF, indicating the device has a positive impact in the real-world setting. Translational Relevance Our suprachoroidal retinal prosthesis shows potential utility in everyday life, by enabling an increased environmental awareness and improving access to sensory information for people with end-stage RP.
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Affiliation(s)
- Lewis Karapanos
- Centre for Eye Research Australia, Royal Victorian Eye & Ear Hospital, East Melbourne, VIC, Australia
- Ophthalmology, Department of Surgery, University of Melbourne, East Melbourne, VIC, Australia
| | - Carla J. Abbott
- Centre for Eye Research Australia, Royal Victorian Eye & Ear Hospital, East Melbourne, VIC, Australia
- Ophthalmology, Department of Surgery, University of Melbourne, East Melbourne, VIC, Australia
| | - Lauren N. Ayton
- Centre for Eye Research Australia, Royal Victorian Eye & Ear Hospital, East Melbourne, VIC, Australia
- Ophthalmology, Department of Surgery, University of Melbourne, East Melbourne, VIC, Australia
- Department of Optometry and Vision Sciences, University of Melbourne, Melbourne, VIC, Australia
| | - Maria Kolic
- Centre for Eye Research Australia, Royal Victorian Eye & Ear Hospital, East Melbourne, VIC, Australia
| | - Myra B. McGuinness
- Centre for Eye Research Australia, Royal Victorian Eye & Ear Hospital, East Melbourne, VIC, Australia
- Melbourne School of Population and Global Health, University of Melbourne, Parkville, VIC, Australia
| | - Elizabeth K. Baglin
- Centre for Eye Research Australia, Royal Victorian Eye & Ear Hospital, East Melbourne, VIC, Australia
| | - Samuel A. Titchener
- Bionics Institute, East Melbourne, VIC, Australia
- Medical Bionics Department, University of Melbourne, Parkville, VIC, Australia
| | - Jessica Kvansakul
- Bionics Institute, East Melbourne, VIC, Australia
- Medical Bionics Department, University of Melbourne, Parkville, VIC, Australia
| | - Dean Johnson
- Specialised Orientation and Mobility, Melbourne, VIC, Australia
| | - William G. Kentler
- Department of Biomedical Engineering, University of Melbourne, Parkville, VIC, Australia
| | - Nick Barnes
- Research School of Engineering, Australian National University, Canberra, ACT, Australia
| | - David A. X. Nayagam
- Bionics Institute, East Melbourne, VIC, Australia
- Department of Pathology, University of Melbourne, St. Vincent's Hospital, Fitzroy, VIC, Australia
| | - Penelope J. Allen
- Centre for Eye Research Australia, Royal Victorian Eye & Ear Hospital, East Melbourne, VIC, Australia
- Ophthalmology, Department of Surgery, University of Melbourne, East Melbourne, VIC, Australia
| | - Matthew A. Petoe
- Bionics Institute, East Melbourne, VIC, Australia
- Medical Bionics Department, University of Melbourne, Parkville, VIC, Australia
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Wang J, Zhu H, Liu J, Li H, Han Y, Zhou R, Zhang Y. The application of computer vision to visual prosthesis. Artif Organs 2021; 45:1141-1154. [PMID: 34318520 DOI: 10.1111/aor.14022] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 04/28/2021] [Accepted: 05/07/2021] [Indexed: 11/27/2022]
Abstract
A visual prosthesis is an auxiliary device for patients with blinding diseases that cannot be treated with conventional surgery or drugs. It converts captured images into corresponding electrical stimulation patterns, according to which phosphenes are generated through the action of internal electrodes on the visual pathway to form visual perception. However, due to some restrictions such as the few implantable electrodes that the biological tissue can accommodate, the induced perception is far from ideal. Therefore, an important issue in visual prosthesis research is how to detect and present useful information in low-resolution prosthetic vision to improve the visual function of the wearer. In recent years, with the development and broad application of computer vision methods, researchers have investigated the possibility of their utilization in visual prostheses by simulating prosthetic visual percepts. Through the optimization of visual perception by image processing, the efficiency of visual prosthesis devices can be further improved to better meet the needs of prosthesis wearers. In this article, recent works on prosthetic vision centering on implementing computer vision methods are reviewed. Differences, strengths, and weaknesses of the mentioned methods are discussed. The development directions of optimizing prosthetic vision and improving methods of visual perception are analyzed.
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Affiliation(s)
- Jing Wang
- School of Information, Shanghai Ocean University, Shanghai, China.,Key Laboratory of Fishery Information, Ministry of Agriculture, Shanghai, China
| | - Haiyi Zhu
- School of Information, Shanghai Ocean University, Shanghai, China
| | - Jianyun Liu
- School of Information, Shanghai Ocean University, Shanghai, China
| | - Heng Li
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Yanling Han
- School of Information, Shanghai Ocean University, Shanghai, China
| | - Ruyan Zhou
- School of Information, Shanghai Ocean University, Shanghai, China
| | - Yun Zhang
- School of Information, Shanghai Ocean University, Shanghai, China.,Key Laboratory of Fishery Information, Ministry of Agriculture, Shanghai, China
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10
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Sadeghi R, Kartha A, Barry MP, Bradley C, Gibson P, Caspi A, Roy A, Dagnelie G. Glow in the dark: Using a heat-sensitive camera for blind individuals with prosthetic vision. Vision Res 2021; 184:23-29. [PMID: 33780753 PMCID: PMC8137663 DOI: 10.1016/j.visres.2021.02.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 02/12/2021] [Accepted: 02/28/2021] [Indexed: 11/29/2022]
Abstract
To date, retinal implants are the only available treatment for blind individuals with retinal degenerations such as retinitis pigmentosa. Argus II is the only visual implant with FDA approval, with more than 300 users worldwide. Argus II stimulation is based on a grayscale image coming from a head-mounted visible-light camera. Normally, the 11°×19° field of view of the Argus II user is full of objects that may elicit similar phosphenes. The prosthesis cannot meaningfully convey so much visual information, and the percept is reduced to an ambiguous impression of light. This study is aimed at investigating the efficacy of simplifying the video input in real-time using a heat-sensitive camera. Data were acquired from four Argus II users in 5 stationary tasks with either hot objects or human targets as stimuli. All tasks were of m-alternative forced choice design where precisely one of the m≥2 response alternatives was defined to be "correct" by the experimenter. To compare performance with heat-sensitive and normal cameras across all tasks, regardless of m, we used an extension of signal detection theory to latent variables, estimating person ability and item difficulty in d' units. Results demonstrate that subject performance was significantly better across all tasks with the thermal camera compared to the regular Argus II camera. The future addition of thermal imaging to devices with very poor spatial resolution may have significant real-life benefits for orientation, personal safety, and social interactions, thereby improving quality of life.
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Affiliation(s)
- Roksana Sadeghi
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Arathy Kartha
- Department of Ophthalmology, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | | | - Chris Bradley
- Department of Ophthalmology, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Paul Gibson
- Advanced Medical Electronics Corporation, Maple Grove, MN, USA
| | - Avi Caspi
- Second Sight Medical Products, Sylmar, CA, USA; Jerusalem College of Technology, Jerusalem, Israel
| | - Arup Roy
- Second Sight Medical Products, Sylmar, CA, USA
| | - Gislin Dagnelie
- Department of Ophthalmology, Johns Hopkins School of Medicine, Baltimore, MD, USA
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11
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Xie H, Wang Y, Ye Z, Fang S, Xu Z, Wu T, Chan LLH. Monitoring Cortical Response and Electrode-Retina Impedance Under Epiretinal Stimulation in Rats. IEEE Trans Neural Syst Rehabil Eng 2021; 29:1178-1187. [PMID: 34152987 DOI: 10.1109/tnsre.2021.3090904] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Retinal prosthesis can restore partial vision in patients with retinal degenerative diseases such as retinitis pigmentosa and age-related macular degeneration. Epiretinal prosthesis is one of three therapeutic approaches, which received regulatory approval several years ago. The thresholds of an epiretinal stimulation is partly determined by the size of the physical gap between the electrode and the retina after implantation. Precise positioning of epiretinal stimulating electrode array is still a challenging task. In this study, we demonstrate an approach to positioning epiretinal prostheses for an optimal response at the cortical output by monitoring both the impedance at the electrode-retina interface and the evoked-potential at the cortical level. We implanted a single-channel electrode on the epiretinal surface in adult rats, acutely, guided by both the impedance at the electrode-retina interface and by electrically evoked potentials (EEPs) in the visual cortex during retinal stimulation. We observe that impedance monotonously increases with decreasing electrode-retina distance, but that the strongest cortical responses were achieved at intermediate impedance levels. When the electrode penetrates the retina, the impedance keeps increasing. The effect of stimulation on the retina changes from epiretinal paradigm to intra-retinal paradigm and a decrease in cortical activation is observed. It is found that high impedance is not always favorable to elicit best cortical responses. Histopathological results showed that the electrode was placed at the intra-retinal space at high impedance value. These results show that monitoring impedance at the electrode-retina interface is necessary but not sufficient in obtaining strong evoked-potentials at the cortical level. Monitoring the cortical EEPs together with the impedance can improve the safety of implantation as well as efficacy of stimulation in the next generation of retinal implants.
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12
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Yamashita K, Tanaka T, Matsuo T, Uchida T. Development and chemical properties of retinal prostheses using photoelectric dyes coupled to polyethylene films with various anions to achieve high durability. Polym J 2021. [DOI: 10.1038/s41428-021-00468-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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13
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Yamashita K, Sundaram P, Uchida T, Matsuo T, Wong W. Modelling the visual response to an OUReP retinal prosthesis with photoelectric dye coupled to polyethylene film. J Neural Eng 2021; 18. [PMID: 33857924 DOI: 10.1088/1741-2552/abf892] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 04/15/2021] [Indexed: 11/12/2022]
Abstract
Objective.Retinal prostheses have been developed to restore vision in blind patients suffering from diseases like retinitis pigmentosa.Approach.A new type of retinal prosthesis called the Okayama University-type retinal prosthesis (OUReP) was developed by chemically coupling photoelectric dyes to a polyethylene film surface. The prosthesis works by passively generating an electric potential when stimulated by light. However, the neurophysiological mechanism of how OUReP stimulates the degenerated retina is unknown.Main results.Here, we explore how the OUReP affects retinal tissues using a finite element model to solve for the potential inside the tissue and an active Hodgkin-Huxley model based on rat vision to predict the corresponding retinal bipolar response.Significance.We show that the OUReP is likely capable of eliciting responses in retinal bipolar cells necessary to generate vision under most ambient conditions.
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Affiliation(s)
- Koichiro Yamashita
- Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Tsushima-Naka, Kita-ku, Okayama 700-8530, Japan
| | - Prathima Sundaram
- Department of Electrical and Computer Engineering, University of Toronto, 40 St. George Street, Toronto, ON M5S 2E4, Canada
| | - Tetsuya Uchida
- Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Tsushima-Naka, Kita-ku, Okayama 700-8530, Japan
| | - Toshihiko Matsuo
- Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University, 2-5-1 Shikata-cho, Kita-ku, Okayama 700-8558, Japan
| | - Willy Wong
- Department of Electrical and Computer Engineering, University of Toronto, 40 St. George Street, Toronto, ON M5S 2E4, Canada
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Stupin DD, Kuzina EA, Abelit AA, Emelyanov AK, Nikolaev DM, Ryazantsev MN, Koniakhin SV, Dubina MV. Bioimpedance Spectroscopy: Basics and Applications. ACS Biomater Sci Eng 2021; 7:1962-1986. [PMID: 33749256 DOI: 10.1021/acsbiomaterials.0c01570] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
In this review, we aim to introduce the reader to the technique of electrical impedance spectroscopy (EIS) with a focus on its biological, biomaterials, and medical applications. We explain the theoretical and experimental aspects of the EIS with the details essential for biological studies, i.e., interaction of metal electrodes with biological matter and liquids, strategies of measurement rate increasing, noise reduction in bio-EIS experiments, etc. We also give various examples of successful bio-EIS practical implementations in science and technology, from whole-body health monitoring and sensors for vision prosthetic care to single living cell examination platforms, virus disease research, biomolecules detection, and implementation of novel biomaterials. The present review can be used as a bio-EIS tutorial for students as well as a handbook for scientists and engineers because of the extensive references covering the contemporary research papers in the field.
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Affiliation(s)
- Daniil D Stupin
- Alferov University, 8/3 Khlopina Street, Saint Petersburg 194021, Russia
| | - Ekaterina A Kuzina
- Alferov University, 8/3 Khlopina Street, Saint Petersburg 194021, Russia
| | - Anna A Abelit
- Alferov University, 8/3 Khlopina Street, Saint Petersburg 194021, Russia.,Peter the Great St. Petersburg Polytechnic University, Polytechnicheskaya 29, St. Petersburg 195251, Russia
| | - Anton K Emelyanov
- Alferov University, 8/3 Khlopina Street, Saint Petersburg 194021, Russia.,Pavlov First Saint Petersburg State Medical University, L'va Tolstogo Street. 6-8, Saint Petersburg 197022, Russia
| | - Dmitrii M Nikolaev
- Alferov University, 8/3 Khlopina Street, Saint Petersburg 194021, Russia
| | - Mikhail N Ryazantsev
- Institute of Chemistry, Saint Petersburg State University, 26 Universitetskii pr, Saint Petersburg 198504, Russia
| | - Sergei V Koniakhin
- Alferov University, 8/3 Khlopina Street, Saint Petersburg 194021, Russia.,Institut Pascal, PHOTON-N2, Université Clermont Auvergne, CNRS, SIGMA Clermont, Clermont-Ferrand F-63000, France
| | - Michael V Dubina
- Institute of Highly Pure Biopreparation of the Federal Medical-Biological Agency, Pudozhskaya 7, St. Petersburg 197110, Russia
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Yamashita K, Tanaka T, Matsuo T, Uchida T. Development of highly durable retinal prosthesis using photoelectric dyes coupled to polyethylene film and quantitative in vitro evaluation of its durability. Biomed Mater 2021; 16. [PMID: 33607636 DOI: 10.1088/1748-605x/abe809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 02/19/2021] [Indexed: 11/11/2022]
Abstract
Retinal prostheses have been developed to restore vision in blind patients suffering from such diseases as retinitis pigmentosa. In our previous studies, we developed a retinal prosthesis called dye-coupled film by chemical coupling of photoelectric dyes, which absorb light and then generate electrical potential, with a polyethylene film surface. The dye-coupled film is nontoxic, and we recovered the vision of a monkey with macular degeneration. The amount of dye on the dye-coupled film, however, decreased to one-third after five months in the monkey's eye. The photoelectric dye consists of a cation with photoresponsivity and a bromide ion (Br-). Therefore, an anion-exchange reaction could be applied to the dye-coupled film to improve its durability. In this study, the anion-exchange reaction was conducted using bis(trifluoromethanesulfonyl)imide ion (TFSI-), which has lower nucleophilicity than Br-. First, the long-term durability was examined without using animal subjects and in a short period. Subsequently, an elemental analysis was performed to confirm the exchange between Br-and TFSI-, and chemical properties, such as photoresponsivity and durability, before and after the anion exchange, were evaluated. It was quantitatively confirmed that the long-term durability of dye-coupled films can be evaluated in an in vitro environment and in a short period of one-thirtieth by utilizing a saline solution at 60°C, compared with an in vivo environment. In addition, the durability of the dye-coupled film with TFSI-was improved to 270%-320% compared with that of the dye-coupled film with Br-.
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Affiliation(s)
- Koichiro Yamashita
- Okayama University - Tsushima Campus, 3-1-1 Tsushimanaka, Kitaku, Okayama, Okayama, 700-8530, JAPAN
| | - Tenu Tanaka
- Okayama University Graduate School of Natural Science and Technology, 3-1-1 Tsushimanaka Kitaku, Okayama, Okayama, 700-8530, JAPAN
| | - Toshihiko Matsuo
- Okayama University, 2-5-1 Shikatacho,, Okayama, Okayama, 700-8558, JAPAN
| | - Tetsuya Uchida
- Okayama University Graduate School of Natural Science and Technology, 3-1-1 Tsushimanaka, Kitaku, Okayama, 700-8530, JAPAN
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Charreyron SL, Boehler Q, Danun AN, Mesot A, Becker M, Nelson BJ. A Magnetically Navigated Microcannula for Subretinal Injections. IEEE Trans Biomed Eng 2021; 68:119-129. [DOI: 10.1109/tbme.2020.2996013] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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17
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Shoffstall AJ, Capadona JR. Bioelectronic Neural Implants. Biomater Sci 2020. [DOI: 10.1016/b978-0-12-816137-1.00073-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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18
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Rachitskaya A, Lane L, Ehlers J, DeBenedictis M, Yuan A. Argus II Retinal Prosthesis Implantation Using Three-Dimensional Visualization System. Retina 2019; 39 Suppl 1:S199-S200. [DOI: 10.1097/iae.0000000000002296] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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19
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Kuehlewein L, Troelenberg N, Stingl K, Schleehauf S, Kusnyerik A, Jackson TL, MacLaren RE, Chee C, Roider J, Wilhelm B, Gekeler F, Bartz‐Schmidt KU, Zrenner E, Stingl K. Changes in microchip position after implantation of a subretinal vision prosthesis in humans. Acta Ophthalmol 2019; 97:e871-e876. [PMID: 30816625 DOI: 10.1111/aos.14077] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Accepted: 02/02/2019] [Indexed: 11/29/2022]
Abstract
PURPOSE Retinal prosthetic devices have been developed to partially restore very low vision in legally blind patients with end-stage hereditary retinal dystrophies. Subretinal implants, unlike epiretinal implants, are not fixated by a tack. The aim of this study was to assess and analyse possible changes over time in the subretinal position of the RETINA IMPLANT Alpha IMS and Alpha AMS (ClinicalTrials.gov NCT01024803). METHODS Imaging studies were performed on fundus photographs using GIMP (Version 2.8.14). Postoperative photographs of the implanted eye were scaled and aligned. Landmarks were chosen and distances between landmarks were measured to then calculate the displacement of the microchip using a transformation matrix for rotational and translational movements. Analyses were performed using MATLAB 8.6 (The MathWorks Inc., Natick, MA). RESULTS Of the 27 datasets with the Alpha IMS device, 12 (44%) remained stable without displacement of the microchip relative to the optic disc and the major blood vessels, whereas in 15 (56%), displacement occurred. The mean ± SD displacement in those 15 eyes was 0.66 ± 0.35 mm (range, 0.24-1.67 mm). Of the eight datasets with the Alpha AMS device, 1 (13%) remained stable without displacement of the microchip relative to the optic disc and the major blood vessels, whereas in 7 (87%), displacement occurred. The mean ± SD displacement in those seven eyes was 0.66 ± 0.26 mm (range, 0.32-0.97 mm). Calculated from all eyes (including those in which no displacement occurred), the mean displacement was 0.36 mm in the IMS cohort, and 0.58 mm in the AMS cohort, however, the difference was not statistically significant (p = 0.17). CONCLUSIONS We have shown that the position of the subretinal implant changes in the majority of the cases after implantation. While the overall mean displacement of the chip was not significantly different in either of the cohorts, the maximum displacement was smaller in the Alpha AMS cohort.
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Affiliation(s)
- Laura Kuehlewein
- Institute for Ophthalmic Research University Eye Hospital Center for Ophthalmology Eberhard Karls University Tuebingen Germany
| | | | - Krunoslav Stingl
- Institute for Ophthalmic Research University Eye Hospital Center for Ophthalmology Eberhard Karls University Tuebingen Germany
| | | | - Akos Kusnyerik
- Department of Ophthalmology Semmelweis University Budapest Hungary
| | - Timothy L. Jackson
- Department of Ophthalmology Faculty of Life Sciences and Medicine King's College London King's College Hospital London UK
| | - Robert E. MacLaren
- Oxford Eye Hospital at the Oxford University Hospitals NHS Foundation Trust and Nuffield Laboratory of Ophthalmology University of Oxford Oxford UK
| | - Caroline Chee
- Department of Ophthalmology National University Hospital Singapore Singapore
| | - Johann Roider
- Department of Ophthalmology University of Kiel Kiel Germany
| | - Barbara Wilhelm
- Institute for Ophthalmic Research University Eye Hospital Center for Ophthalmology Eberhard Karls University Tuebingen Germany
| | - Florian Gekeler
- Institute for Ophthalmic Research University Eye Hospital Center for Ophthalmology Eberhard Karls University Tuebingen Germany
| | - Karl Ulrich Bartz‐Schmidt
- Institute for Ophthalmic Research University Eye Hospital Center for Ophthalmology Eberhard Karls University Tuebingen Germany
| | - Eberhart Zrenner
- Institute for Ophthalmic Research University Eye Hospital Center for Ophthalmology Eberhard Karls University Tuebingen Germany
- Werner Reichardt Centre for Integrative Neuroscience Eberhard Karls University Tuebingen Tuebingen Germany
| | - Katarina Stingl
- Institute for Ophthalmic Research University Eye Hospital Center for Ophthalmology Eberhard Karls University Tuebingen Germany
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Rizzo S, Barale PO, Ayello-Scheer S, Devenyi RG, Delyfer MN, Korobelnik JF, Rachitskaya A, Yuan A, Jayasundera KT, Zacks DN, Handa JT, Montezuma SR, Koozekanani D, Stanga P, da Cruz L, Walter P, Augustin AJ, Olmos de Koo LC, Ho AC, Kirchhof B, Hahn P, Vajzovic L, Iezzi R, Gaucher D, Arevalo JF, Gregori NZ, Wiedemann P, Özmert E, Lim JI, Rezende FA, Huang SS, Merlini F, Patel U, Greenberg RJ, Justus S, Bacherini D, Cinelli L, Humayun MS. Hypotony and the Argus II retinal prosthesis: causes, prevention and management. Br J Ophthalmol 2019; 104:518-523. [DOI: 10.1136/bjophthalmol-2019-314135] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 06/23/2019] [Accepted: 06/24/2019] [Indexed: 01/15/2023]
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21
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Rountree CM, Troy JB, Saggere L. Investigation of Injection Depth for Subretinal Delivery of Exogenous Glutamate to Restore Vision via Biomimetic Chemical Neuromodulation. IEEE Trans Biomed Eng 2019; 67:464-470. [PMID: 31071013 DOI: 10.1109/tbme.2019.2915255] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Chemical neuromodulation of the retina using native neurotransmitters to biomimetically activate target retinal neurons through chemical synapses is a promising biomimetic alternative to electrical stimulation for restoring vision in blindness caused by photoreceptor degenerative diseases. Recent research has shown that subretinal chemical stimulation could be advantageous for treating photoreceptor degenerative diseases but many of the parameters for achieving efficacious chemical neuromodulation are yet to be explored. In this paper, we investigated how the depth at which neurotransmitter is injected subretinally affects the success rate, spike rate characteristics (i.e., amplitude, response latency, and time width), and spatial resolution of chemical stimulation in wild-type Long Evans and photoreceptor degenerated S334ter-3 transgenic rat retinas in vitro. We compared the responses to injections of glutamate at the subretinal surface and two subsurface depths near the outer and inner plexiform layers and found that while injections at all depths elicited robust retinal ganglion cell responses, they differed significantly in terms of the spike rate characteristics and spatial resolutions across injection depths. Shallow subsurface injections near the outer plexiform layer evoked the highest spike rate amplitudes and had the highest spatial resolution and success rates, while deep subsurface injections near the inner plexiform layer elicited the shortest latencies and narrowest time widths. Our results suggest that surface injections are suboptimal for subretinal chemical neuromodulation, while shallow subsurface and deep subsurface injections may optimize high spatial and high temporal resolution, respectively. These findings have great significance for the design and development of a potential neurotransmitter-based subretinal prosthesis.
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22
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Bae SH, Jeong J, Kim SJ, Chung H, Seo JM. Investigation of Surgical Techniques for Optimization of Long-Term Outcomes of LCP-Based Retinal Prosthesis Implantation. Transl Vis Sci Technol 2018; 7:17. [PMID: 30159210 PMCID: PMC6108533 DOI: 10.1167/tvst.7.4.17] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 07/02/2018] [Indexed: 01/09/2023] Open
Abstract
Purpose To investigate reproducible surgical techniques to optimize the long-term safety of liquid crystal polymer (LCP)-based retinal prosthesis implantation. Methods An LCP-based retinal prosthesis is fabricated monolithically on a single-body LCP substrate with all components, including the package and electrode array. We implanted the electrode array into the suprachoroidal space and anchored the package and transition part to the sclera in rabbits (n = 11). The safety profile was assessed upon the completion of the surgery and postoperatively. Results The surgical procedures for implantation of the entire system were easily performed in nine eyes (81.8%) without any intraoperative complications. In the other two eyes (18.2%), surgical complications related to electrode insertion, including optic nerve damage and retinal tear, arose. In 10 eyes (90.9%), the devices were well tolerated for at least 3 months. However, in most eyes (nine; 81.8%), two complications began to appear after 3 months, postoperatively, including conjunctival erosion or dehiscence over the package or transition part. The electrode arrays were maintained safely in the suprachoroidal space after surgery without any complications, regardless of the status of the extraocular components in all cases except two intraoperative complications. Conclusions We established safe and reproducible surgical techniques for implantation of our LCP-based retinal prosthesis into the suprachoroidal space. Although issues related to surgical technique or device configuration were identified, further technical solutions would improve the long-term safety of device implantation. Translational Relevance This study presents successful implantation of LCP-based retinal prosthesis. The technical solutions will permit an optimization of surgical techniques.
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Affiliation(s)
- So Hyun Bae
- Department of Ophthalmology, Kangnam Sacred Heart Hospital, College of Medicine, Hallym University, Seoul, Republic of Korea.,Interdisciplinary Program for Bioengineering, Seoul National University, Seoul, Republic of Korea
| | - Joonsoo Jeong
- School of Engineering, Brown University, Providence, RI, USA
| | - Sung June Kim
- Department of Electrical and Computer Engineering, Inter-University Semiconductor Research Center, Institute of Engineering Research, Seoul National University, Seoul, Republic of Korea
| | - Hum Chung
- Department of Ophthalmology, Chung-Ang University Hospital, Seoul, Republic of Korea
| | - Jong-Mo Seo
- Interdisciplinary Program for Bioengineering, Seoul National University, Seoul, Republic of Korea.,Department of Electrical and Computer Engineering, Inter-University Semiconductor Research Center, Institute of Engineering Research, Seoul National University, Seoul, Republic of Korea.,Department of Ophthalmology, Biomedical Research Institute, Seoul National University Hospital, Seoul, Republic of Korea
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23
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Fernandez E. Development of visual Neuroprostheses: trends and challenges. Bioelectron Med 2018; 4:12. [PMID: 32232088 PMCID: PMC7098238 DOI: 10.1186/s42234-018-0013-8] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2018] [Accepted: 07/27/2018] [Indexed: 02/06/2023] Open
Abstract
Visual prostheses are implantable medical devices that are able to provide some degree of vision to individuals who are blind. This research field is a challenging subject in both ophthalmology and basic science that has progressed to a point where there are already several commercially available devices. However, at present, these devices are only able to restore a very limited vision, with relatively low spatial resolution. Furthermore, there are still many other open scientific and technical challenges that need to be solved to achieve the therapeutic benefits envisioned by these new technologies. This paper provides a brief overview of significant developments in this field and introduces some of the technical and biological challenges that still need to be overcome to optimize their therapeutic success, including long-term viability and biocompatibility of stimulating electrodes, the selection of appropriate patients for each artificial vision approach, a better understanding of brain plasticity and the development of rehabilitative strategies specifically tailored for each patient.
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Affiliation(s)
- Eduardo Fernandez
- Institute of Bioengineering, University Miguel Hernández and CIBER-BBN, Avda de la Universidad, s/n, 03202 Alicante, Elche Spain.,2John A. Moran Eye Center, University of Utah, Salt Lake City, USA
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Matsuo T, Uchida T, Sakurai J, Yamashita K, Matsuo C, Araki T, Yamashita Y, Kamikawa K. Visual Evoked Potential Recovery by Subretinal Implantation of Photoelectric Dye-Coupled Thin Film Retinal Prosthesis in Monkey Eyes With Macular Degeneration. Artif Organs 2018; 42:E186-E203. [PMID: 29633282 PMCID: PMC6175213 DOI: 10.1111/aor.13120] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 12/30/2017] [Accepted: 01/02/2018] [Indexed: 12/23/2022]
Abstract
Retinal prosthesis or artificial retina is a promising modality of treatment for outer retinal degeneration, caused by primary and secondary loss of photoreceptor cells, in hereditary retinal dystrophy and age‐related macular degeneration, respectively. Okayama University‐type retinal prosthesis (OUReP) is a photoelectric dye‐coupled polyethylene film which generates electric potential in response to light and stimulates nearby neurons. The dye‐coupled films were implanted by vitreous surgery in the subretinal space of monkey eyes with macular degeneration which had been induced by cobalt chloride injection from the scleral side. A pilot 1‐month observation study involved 6 monkeys and a pivotal 6‐month observation study involved 8 monkeys. Of 8 monkeys in 6‐month group, 3 monkeys underwent dye‐coupled film removal at 5 months and were observed further for 1 month. The amplitude of visual evoked potential which had been reduced by macular degeneration did recover at 1 month after film implantation and maintained the level at 6 months. Optical coherence tomography showed no retinal detachment, and full‐field electroretinograms maintained a‐wave and b‐wave amplitudes, indicative of no retinal toxicity. Pathological examinations after 6‐month implantation showed structural integrity of the inner retinal layer in close apposition to dye‐coupled films. The implanted films which were removed by vitrectomy 5 months later showed light‐evoked surface electric potentials by scanning Kelvin probe measurement. The photoelectric dye‐coupled film (OUReP), which serves as a light‐receiver and a displacement current generator in the subretinal space of the eye, has a potential for recovering vision in diseases with photoreceptor cell loss, such as retinitis pigmentosa and age‐related macular degeneration.
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Affiliation(s)
- Toshihiko Matsuo
- Department of Ophthalmology, Okayama University Medical School and Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama City, Japan
| | - Tetsuya Uchida
- Department of Polymer Materials Science, Okayama University Faculty of Engineering and Graduate School of Natural Science and Technology, Okayama City, Japan
| | - Jun Sakurai
- Center for Innovative Clinical Medicine, Okayama University Hospital, Okayama City, Japan
| | - Koichiro Yamashita
- Department of Polymer Materials Science, Okayama University Faculty of Engineering and Graduate School of Natural Science and Technology, Okayama City, Japan
| | - Chie Matsuo
- Department of Orthodontist, Okayama City, Japan
| | - Tomoaki Araki
- Department of Shin Nippon Biomedical Laboratories, Ltd., Kagoshima City, Japan
| | - Yusuke Yamashita
- Department of Shin Nippon Biomedical Laboratories, Ltd., Kagoshima City, Japan
| | - Kunihisa Kamikawa
- Center for Innovative Clinical Medicine, Okayama University Hospital, Okayama City, Japan
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25
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Delyfer MN, Gaucher D, Govare M, Cougnard-Grégoire A, Korobelnik JF, Ajana S, Mohand-Saïd S, Ayello-Scheer S, Rezaiguia-Studer F, Dollfus H, Sahel JA, Barale PO. Adapted Surgical Procedure for Argus II Retinal Implantation: Feasibility, Safety, Efficiency, and Postoperative Anatomic Findings. ACTA ACUST UNITED AC 2018; 2:276-287. [DOI: 10.1016/j.oret.2017.08.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 08/01/2017] [Accepted: 08/08/2017] [Indexed: 11/17/2022]
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26
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Abdallah W, Li W, Weiland J, Humayun M, Ameri H. Implantation of multiple suprachoroidal electrode arrays in rabbits. J Curr Ophthalmol 2018; 30:68-73. [PMID: 29564412 PMCID: PMC5859463 DOI: 10.1016/j.joco.2017.11.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 11/06/2017] [Accepted: 11/10/2017] [Indexed: 11/23/2022] Open
Abstract
Purpose Epiretinal and subretinal prosthesis have been shown to be a valid way to provide some vision to patients with advanced outer retinal degeneration and profound vision loss. However, the field of vision for these patients is markedly limited by the area occupied by the electrode array. In this study, we aimed to evaluate the feasibility of implantation of multiple suprachoroidal electrode arrays in a single eye in order to increase the field of vision in patients implanted with retinal prosthesis. Methods The right eye of seventeen Dutch rabbits (age range, 5–6 months) was used for the study. Multiple inactive custom-made electrode arrays were inserted into the suprachoroidal space (SCS) and animals were followed up for up to 6 months using fundus photography, optical coherence tomography (OCT), and fluorescein angiography (FA). Results It was possible to surgically implant up to 8 electrode arrays in a single eye. None of the rabbits showed any major complications. The electrodes were well tolerated and remained in position in all rabbits. There was no evidence of retinal damage on follow-up exams and FA throughout the study. Conclusion Multiple suprachoroidal electrode array implantation is feasible and may provide a novel approach to increase the field of vision in subjects implanted with retinal prosthesis.
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Affiliation(s)
- Walid Abdallah
- Department of Ophthalmology, USC Roski Eye Institute, Keck School of Medicine of the University of Southern California, Los Angeles, CA, USA
| | - Wen Li
- Department of Electrical and Computer Engineering, Michigan State University, East Lansing, MI, USA
| | - James Weiland
- Department of Ophthalmology, USC Roski Eye Institute, Keck School of Medicine of the University of Southern California, Los Angeles, CA, USA
| | - Mark Humayun
- Department of Ophthalmology, USC Roski Eye Institute, Keck School of Medicine of the University of Southern California, Los Angeles, CA, USA
| | - Hossein Ameri
- Department of Ophthalmology, USC Roski Eye Institute, Keck School of Medicine of the University of Southern California, Los Angeles, CA, USA
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Sanjuan-Alberte P, Alexander MR, Hague RJM, Rawson FJ. Electrochemically stimulating developments in bioelectronic medicine. Bioelectron Med 2018; 4:1. [PMID: 32232077 PMCID: PMC7098225 DOI: 10.1186/s42234-018-0001-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 02/13/2018] [Indexed: 12/22/2022] Open
Abstract
Cellular homeostasis is in part controlled by biological generated electrical activity. By interfacing biology with electronic devices this electrical activity can be modulated to actuate cellular behaviour. There are current limitations in merging electronics with biology sufficiently well to target and sense specific electrically active components of cells. By addressing this limitation, researchers give rise to new capabilities for facilitating the two-way transduction signalling mechanisms between the electronic and cellular components. This is required to allow significant advancement of bioelectronic technology which offers new ways of treating and diagnosing diseases. Most of the progress that has been achieved to date in developing bioelectronic therapeutics stimulate neural communication, which ultimately orchestrates organ function back to a healthy state. Some devices used in therapeutics include cochlear and retinal implants and vagus nerve stimulators. However, all cells can be impacted by electrical inputs which gives rise to the opportunity to broaden the use of bioelectronic medicine for treating disease. Electronic actuation of non-excitable cells has been shown to lead to ‘programmed’ cell behaviour via application of electronic input which alter key biological processes. A neglected form of cellular electrical communication which has not yet been considered when developing bioelectronic therapeutics is faradaic currents. These are generated during redox reactions. A precedent of electrochemical technology being used to modulate these reactions, thereby controlling cell behaviour, has already been set. In this mini review we highlight the current state of the art of electronic routes to modulating cell behaviour and identify new ways in which electrochemistry could be used to contribute to the new field of bioelectronic medicine.
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Affiliation(s)
- Paola Sanjuan-Alberte
- 1Regenerative Medicine and Cellular Therapies, School of Pharmacy, University of Nottingham, Nottingham, NG7 2QL UK.,2Centre for Additive Manufacturing, School of Engineering, University of Nottingham, Nottingham, NG7 2QL UK
| | - Morgan R Alexander
- 3Advanced Materials and Healthcare Technologies, School of Pharmacy, University of Nottingham, Nottingham, NG7 2QL UK
| | - Richard J M Hague
- 2Centre for Additive Manufacturing, School of Engineering, University of Nottingham, Nottingham, NG7 2QL UK
| | - Frankie J Rawson
- 1Regenerative Medicine and Cellular Therapies, School of Pharmacy, University of Nottingham, Nottingham, NG7 2QL UK
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29
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Rountree CM, Troy JB, Saggere L. Methodology for Biomimetic Chemical Neuromodulation of Rat Retinas with the Neurotransmitter Glutamate In Vitro. J Vis Exp 2017. [PMID: 29286422 DOI: 10.3791/56645] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Photoreceptor degenerative diseases cause irreparable blindness through the progressive loss of photoreceptor cells in the retina. Retinal prostheses are an emerging treatment for photoreceptor degenerative diseases that seek to restore vision by artificially stimulating the surviving retinal neurons in the hope of eliciting comprehensible visual perception in patients. Current retinal prostheses have demonstrated success in restoring limited vision to patients using an array of electrodes to electrically stimulate the retina but face substantial physical barriers in restoring high acuity, natural vision to patients. Chemical neurostimulation using native neurotransmitters is a biomimetic alternative to electrical stimulation and could bypass the fundamental limitations associated with retinal prostheses using electrical neurostimulation. Specifically, chemical neurostimulation has the potential to restore more natural vision with comparable or better visual acuities to patients by injecting very small quantities of neurotransmitters, the same natural agents of communication used by retinal chemical synapses, at much finer resolution than current electrical prostheses. However, as a relatively unexplored stimulation paradigm, there is no established protocol for achieving chemical stimulation of the retina in vitro. The purpose of this work is to provide a detailed framework for accomplishing chemical stimulation of the retina for investigators who wish to study the potential of chemical neuromodulation of the retina or similar neural tissues in vitro. In this work, we describe the experimental setup and methodology for eliciting retinal ganglion cell (RGC) spike responses similar to visual light responses in wild-type and photoreceptor-degenerated wholemount rat retinas by injecting controlled volumes of the neurotransmitter glutamate into the subretinal space using glass micropipettes and a custom multiport microfluidic device. This methodology and protocol are general enough to be adapted for neuromodulation using other neurotransmitters or even other neural tissues.
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Affiliation(s)
- Corey M Rountree
- Department of Mechanical and Industrial Engineering, University of Illinois at Chicago
| | - John B Troy
- Department of Biomedical Engineering, Northwestern University
| | - Laxman Saggere
- Department of Mechanical and Industrial Engineering, University of Illinois at Chicago;
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Meyniel C, Bodaghi B, Robert PY. Revisiting Vision Rehabilitation. Front Syst Neurosci 2017; 11:82. [PMID: 29163077 PMCID: PMC5671942 DOI: 10.3389/fnsys.2017.00082] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Accepted: 10/16/2017] [Indexed: 11/21/2022] Open
Abstract
Low vision is a condition caused by eye or brain disease, in which visual acuity is 20/70 (3/10 or 6/18) or poorer in the better-seeing eye and cannot be corrected or improved with regular eyeglasses. It impacts personal ability to perform vision-dependent tasks as activities of daily living, walking, reading or using a computer. Rehabilitation is a multidisciplinary training dedicated to improve patients’ functional abilities and quality of life. It has to be personalized to every individual situation, whatever the underlying pathology.
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Affiliation(s)
- Claire Meyniel
- Department of Neurophysiology, Pitié-Salpêtrière Hospital, Paris, France.,Department of Ophthalmology, University of Pierre et Marie Curie, Paris-Sorbonne University, Paris, France
| | - Bahram Bodaghi
- Department of Ophthalmology, University of Pierre et Marie Curie, Paris-Sorbonne University, Paris, France.,Department of Ophthalmology, Pitié-Salpêtrière Hospital, Paris, France
| | - Pierre-Yves Robert
- Department of Ophthalmology, Limoges Hospital, Limoges, France.,Department of Ophthalmology, University of Limoges, Limoges, France
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Abstract
The first medical device to restore a human sense, a cochlear implant converts sound into a train of current pulses that directly stimulate the auditory nerve of a profoundly deaf ear.
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