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Balamur R, Eren GO, Kaleli HN, Karatum O, Kaya L, Hasanreisoglu M, Nizamoglu S. A Retina-Inspired Optoelectronic Synapse Using Quantum Dots for Neuromorphic Photostimulation of Neurons. Adv Sci (Weinh) 2024; 11:e2401753. [PMID: 38447181 PMCID: PMC11095222 DOI: 10.1002/advs.202401753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Indexed: 03/08/2024]
Abstract
Neuromorphic electronics, inspired by the functions of neurons, have the potential to enable biomimetic communication with cells. Such systems require operation in aqueous environments, generation of sufficient levels of ionic currents for neurostimulation, and plasticity. However, their implementation requires a combination of separate devices, such as sensors, organic synaptic transistors, and stimulation electrodes. Here, a compact neuromorphic synapse that combines photodetection, memory, and neurostimulation functionalities all-in-one is presented. The artificial photoreception is facilitated by a photovoltaic device based on cell-interfacing InP/ZnS quantum dots, which induces photo-faradaic charge-transfer mediated plasticity. The device sends excitatory post-synaptic currents exhibiting paired-pulse facilitation and post-tetanic potentiation to the hippocampal neurons via the biohybrid synapse. The electrophysiological recordings indicate modulation of the probability of action potential firing due to biomimetic temporal summation of excitatory post-synaptic currents. The results pave the way for the development of novel bioinspired neuroprosthetics and soft robotics and highlight the potential of quantum dots for achieving versatile neuromorphic functionality in aqueous environments.
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Affiliation(s)
- Ridvan Balamur
- Department of Electrical and Electronics EngineeringKoç UniversityIstanbul34450Türkiye
| | - Guncem Ozgun Eren
- Department of Biomedical Science and EngineeringKoç UniversityIstanbul34450Türkiye
| | - Humeyra Nur Kaleli
- Research Center for Translational MedicineKoç UniversityIstanbul34450Türkiye
| | - Onuralp Karatum
- Department of Electrical and Electronics EngineeringKoç UniversityIstanbul34450Türkiye
| | - Lokman Kaya
- Department of Electrical and Electronics EngineeringKoç UniversityIstanbul34450Türkiye
| | - Murat Hasanreisoglu
- Research Center for Translational MedicineKoç UniversityIstanbul34450Türkiye
| | - Sedat Nizamoglu
- Department of Electrical and Electronics EngineeringKoç UniversityIstanbul34450Türkiye
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Balamur R, Eren GO, Kaleli HN, Karatum O, Kaya L, Hasanreisoglu M, Nizamoglu S. A Retina-Inspired Optoelectronic Synapse Using Quantum Dots for Neuromorphic Photostimulation of Neurons. Adv Sci (Weinh) 2024:e2306097. [PMID: 38514908 DOI: 10.1002/advs.202306097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 01/08/2024] [Indexed: 03/23/2024]
Abstract
Neuromorphic electronics, inspired by the functions of neurons, have the potential to enable biomimetic communication with cells. Such systems require operation in aqueous environments, generation of sufficient levels of ionic currents for neurostimulation, and plasticity. However, their implementation requires a combination of separate devices, such as sensors, organic synaptic transistors, and stimulation electrodes. Here, a compact neuromorphic synapse that combines photodetection, memory, and neurostimulation functionalities all-in-one is presented. The artificial photoreception is facilitated by a photovoltaic device based on cell-interfacing InP/ZnS quantum dots, which induces photo-faradaic charge-transfer mediated plasticity. The device sends excitatory post-synaptic currents exhibiting paired-pulse facilitation and post-tetanic potentiation to the hippocampal neurons via the biohybrid synapse. The electrophysiological recordings indicate modulation of the probability of action potential firing due to biomimetic temporal summation of excitatory post-synaptic currents. These results pave the way for the development of novel bioinspired neuroprosthetics and soft robotics, and highlight the potential of quantum dots for achieving versatile neuromorphic functionality in aqueous environments.
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Affiliation(s)
- Ridvan Balamur
- Department of Electrical and Electronics Engineering, Koç University, Istanbul, 34450, Türkiye
| | - Guncem Ozgun Eren
- Department of Biomedical Science and Engineering, Koç University, Istanbul, 34450, Türkiye
| | - Humeyra Nur Kaleli
- Research Center for Translational Medicine, Koç University, Istanbul, 34450, Türkiye
| | - Onuralp Karatum
- Department of Electrical and Electronics Engineering, Koç University, Istanbul, 34450, Türkiye
| | - Lokman Kaya
- Department of Electrical and Electronics Engineering, Koç University, Istanbul, 34450, Türkiye
| | - Murat Hasanreisoglu
- Research Center for Translational Medicine, Koç University, Istanbul, 34450, Türkiye
| | - Sedat Nizamoglu
- Department of Electrical and Electronics Engineering, Koç University, Istanbul, 34450, Türkiye
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Moorthy VM, Rathnasami JD, Srivastava VM. Design Optimization and Characterization with Fabrication of Nanomaterials-Based Photo Diode Cell for Subretinal Implant Application. Nanomaterials (Basel) 2023; 13:934. [PMID: 36903812 PMCID: PMC10005570 DOI: 10.3390/nano13050934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 02/28/2023] [Accepted: 03/02/2023] [Indexed: 06/18/2023]
Abstract
An ultrathin nano photodiode array fabricated in a flexible substrate can be an ideal therapeutic replacement for degenerated photoreceptor cells damaged by Age-related Macula Degeneration (AMD) and Retinitis Pigmentosa (RP), such as retinal infections. Silicon-based photodiode arrays have been attempted as artificial retinas. Considering the difficulties caused by hard silicon subretinal implants, researchers have diverted their attention towards organic photovoltaic cells-based subretinal implants. Indium-Tin Oxide (ITO) has been a favorite choice as an anode electrode. A mix of poly(3-hexylthiophene) and [6,6]-phenyl C61-butyric acid methyleste (P3HT: PCBM) has been utilized as an active layer in such nanomaterial-based subretinal implants. Though encouraging results have been obtained during the trial of such retinal implants, the need to replace ITO with a suitable transparent conductive electrode will be a suitable substitute. Further, conjugated polymers have been used as active layers in such photodiodes and have shown delamination in the retinal space over time despite their biocompatibility. This research attempted to fabricate and characterize Bulk Hetero Junction (BHJ) based Nano Photo Diode (NPD) utilizing Graphene-polyethylene terephthalate (G-PET)/semiconducting Single-Wall Carbon Nano Tubes (s-SWCNT): fullerene (C60) blend/aluminium (Al) structure to determine the issues in the development of subretinal prosthesis. An effective design approach adopted in this analysis has resulted in developing an NPD with an Efficiency of 10.1% in a non-ITO-driven NPD structure. Additionally, the results show that the efficiency can be further improved by increasing active layer thickness.
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Affiliation(s)
- Vijai M. Moorthy
- Department of Electronic Engineering, Howard College, University of KwaZulu-Natal, Durban 4041, South Africa
| | - Joseph D. Rathnasami
- Department of Electronics and Instrumentation Engineering, Faculty of Engineering and Technology, Annamalai University, Chidambaram 608 002, India
| | - Viranjay M. Srivastava
- Department of Electronic Engineering, Howard College, University of KwaZulu-Natal, Durban 4041, South Africa
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Wu J, Rountree CM, Kare SS, Ramkumar PK, Finan JD, Troy JB. Progress on Designing a Chemical Retinal Prosthesis. Front Cell Neurosci 2022; 16:898865. [PMID: 35774083 PMCID: PMC9239740 DOI: 10.3389/fncel.2022.898865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Accepted: 05/17/2022] [Indexed: 11/29/2022] Open
Abstract
The last major review of progress toward a chemical retinal prosthesis was a decade ago. Many important advancements have been made since then with the aim of producing an implantable device for animal testing. We review that work here discussing the potential advantages a chemical retinal prosthesis may possess, the spatial and temporal resolutions it might provide, the materials from which an implant might be constructed and its likely effectiveness in stimulating the retina in a natural fashion. Consideration is also given to implant biocompatibility, excitotoxicity of dispensed glutamate and known changes to photoreceptor degenerate retinas.
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Affiliation(s)
- Jiajia Wu
- Department of Biomedical Engineering, Robert R. McCormick School of Engineering and Applied Science, Northwestern University, Evanston, IL, United States
| | - Corey M. Rountree
- Department of Mechanical and Industrial Engineering, College of Engineering, University of Illinois at Chicago, Chicago, IL, United States
| | - Sai-Siva Kare
- Department of Mechanical and Industrial Engineering, College of Engineering, University of Illinois at Chicago, Chicago, IL, United States
| | - Pradeep Kumar Ramkumar
- Department of Mechanical and Industrial Engineering, College of Engineering, University of Illinois at Chicago, Chicago, IL, United States
| | - John D. Finan
- Department of Mechanical and Industrial Engineering, College of Engineering, University of Illinois at Chicago, Chicago, IL, United States
| | - John B. Troy
- Department of Biomedical Engineering, Robert R. McCormick School of Engineering and Applied Science, Northwestern University, Evanston, IL, United States
- *Correspondence: John B. Troy,
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Faber H, Ernemann U, Sachs H, Gekeler F, Danz S, Koitschev A, Besch D, Bartz-Schmidt KU, Zrenner E, Stingl K, Kernstock C. CT Assessment of Intraorbital Cable Movement of Electronic Subretinal Prosthesis in Three Different Surgical Approaches. Transl Vis Sci Technol 2021; 10:16. [PMID: 34264295 PMCID: PMC8299430 DOI: 10.1167/tvst.10.8.16] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Purpose Electronic retinal implants restore some visual perception in patients blind from retinitis pigmentosa. Eye movements cause mechanical stress in intraorbital power supply cables leading to cable breaks. By using computer tomography (CT) scans at the extreme positions of the four cardinal gaze directions, this study determined in vivo, which of three surgical routing techniques results in minimal bending radius variation and favors durability. Methods Nine patients received the first-generation subretinal implant Alpha IMS (Retina Implant AG, Reutlingen, Germany) in one eye. Three techniques for intraorbital cable routing were used (straight cable route (A), parabulbar loop (B), and encircling band (C)), each in three patients. All patients underwent computer tomography of the orbital region. The bending radius of the intraorbital cable was measured with the DICOM viewer Osirix v4.1.2 (Pixmeo SARL, Bernex, Switzerland) and served as indicator for mechanical stress. Results Average bending radius variation was 87% for method A, 11% for method B, and 16% for method C. Methods A and B (P = 0.005) and methods A and C (P = 0.007) differed significantly, while method B and C showed no statistical difference (P = 0.07). Conclusions Compared to straight routes, arcuated cable routes significantly reduce cable movement and bending. Due to an easier surgical procedure, a parabulbar loop is the preferred method to minimize bending radius variation and prolong survival time of electronic subretinal implants. Translational Relevance CT analysis of cable bending of implanted medical devices allows to determine which surgical routing technique favors durability in vivo.
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Affiliation(s)
- Hanna Faber
- University Eye Hospital, Center for Ophthalmology, University of Tuebingen, Tuebingen, Germany
| | - Ulrike Ernemann
- Department of Diagnostic and Interventional Neuroradiology, Radiological Clinic, University of Tuebingen, Tuebingen, Germany
| | - Helmut Sachs
- Ophthalmology Clinic, Städtisches Klinikum Dresden Friedrichstadt, Dresden, Germany
| | - Florian Gekeler
- Ophthalmology Clinic, Klinikum Stuttgart, Stuttgart, Germany
| | - Søren Danz
- Radiologische Praxis Hofbauer Danz Fischer, Sindelfingen, Germany
| | - Assen Koitschev
- Clinic for Ear, Nose and Throat Disorders, Plastic Surgery, Klinikum Stuttgart, Stuttgart, Germany
| | - Dorothea Besch
- University Eye Hospital, Center for Ophthalmology, University of Tuebingen, Tuebingen, Germany
| | | | - Eberhart Zrenner
- University Eye Hospital, Center for Ophthalmology, University of Tuebingen, Tuebingen, Germany.,Institute for Ophthalmic Research, Center for Ophthalmology, University of Tuebingen, Tuebingen, Germany.,Werner Reichardt Centre for Integrative Neuroscience, University of Tuebingen, Tuebingen, Germany
| | - Katarina Stingl
- University Eye Hospital, Center for Ophthalmology, University of Tuebingen, Tuebingen, Germany.,Center of Rare Eye Diseases, University of Tuebingen, Tuebingen, Germany
| | - Christoph Kernstock
- University Eye Hospital, Center for Ophthalmology, University of Tuebingen, Tuebingen, Germany
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Bagewadi S, Parameswaran S, Krishnakumar S, Sethuraman S, Subramanian A. Tissue engineering approaches towards the regeneration of biomimetic scaffolds for age-related macular degeneration. J Mater Chem B 2021; 9:5935-5953. [PMID: 34254105 DOI: 10.1039/d1tb00976a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Age-related macular degeneration (AMD) is the third major cause of blindness in people aged above 60 years. It causes dysfunction of the retinal pigment epithelium (RPE) and leads to an irreversible loss of central vision. The present clinical treatment options are more palliative in controlling the progression of the disease and do not functionally restore the degenerated RPE monolayer and photoreceptors. Currently, the clinical transplantation of RPE cells has shown poor engraftment potential due to the absence of an intact Bruch's membrane in AMD patients, thereby the vision is unable to be restored completely. Although tissue engineering strategies target the development of Bruch's membrane-mimetic substrates, the challenge still lies in the development of an ultrathin, biologically and mechanically equivalent membrane to restore visual acuity. Further, existing limitations such as cellular aggregation, surgical complications including retinal tissue damage, tissue rejection, disease transmission, inferior mechanical strength, and the loss of vision over time demand the search for an ideal strategy to restore the functional RPE. Hence, this review aims to provide insights into various approaches, from conventional cell therapy to 3D bioprinting, and their unmet challenges in treating AMD by outlining the pathophysiology of AMD and the host tissue response with respect to injury, treatment and preclinical animal models.
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Affiliation(s)
- Shambhavi Bagewadi
- Tissue Engineering & Additive Manufacturing (TEAM) Lab, Centre for Nanotechnology & Advanced Biomaterials, ABCDE Innovation Centre, School of Chemical & Biotechnology, SASTRA Deemed University, Thanjavur 613 401, Tamil Nadu, India.
| | - Sowmya Parameswaran
- Radheshyam Kanoi Stem Cell Laboratory, Kamalnayan Bajaj Institute for Research in Vision and Ophthalmology Vision Research Foundation, Chennai, India
| | - Subramanian Krishnakumar
- Radheshyam Kanoi Stem Cell Laboratory, Kamalnayan Bajaj Institute for Research in Vision and Ophthalmology Vision Research Foundation, Chennai, India
| | - Swaminathan Sethuraman
- Tissue Engineering & Additive Manufacturing (TEAM) Lab, Centre for Nanotechnology & Advanced Biomaterials, ABCDE Innovation Centre, School of Chemical & Biotechnology, SASTRA Deemed University, Thanjavur 613 401, Tamil Nadu, India.
| | - Anuradha Subramanian
- Tissue Engineering & Additive Manufacturing (TEAM) Lab, Centre for Nanotechnology & Advanced Biomaterials, ABCDE Innovation Centre, School of Chemical & Biotechnology, SASTRA Deemed University, Thanjavur 613 401, Tamil Nadu, India.
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Faber H, Besch D, Bartz‐Schmidt K, Eisenstein H, Roider J, Sachs H, Gekeler F, Zrenner E, Stingl K. Restriction of eye motility in patients with RETINA IMPLANT Alpha AMS. Acta Ophthalmol 2020; 98:e998-e1003. [PMID: 32304165 DOI: 10.1111/aos.14435] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2019] [Accepted: 03/16/2020] [Indexed: 12/22/2022]
Abstract
PURPOSE To evaluate the motility of the eye in patients with the RETINA IMPLANT Alpha AMS. METHODS Eye motility was determined in eight gaze directions in ten blind retinitis pigmentosa patients, who had received the RETINA IMPLANT Alpha AMS, before implantation of the subretinal implant and at six time-points up to one year after. RESULTS The analysis of eye motility showed a restriction in the upgaze and gaze to the temporal side directly after surgery in eight of the nine patients included. The degree of motility restriction decreased continuously with recovery during the observation time. One year after surgery, eye motility was still restricted in the majority of patients, especially in the upgaze to the temporal side at 20° (five of seven patients). CONCLUSION Retinal implants with intraorbital parts (e.g. connecting cables) caused restriction in the temporal and superior viewing directions in the majority of patients. Although this restriction might be cosmetically visible, this limitation in eye motility has no effects on the monocular vision and the implant's efficacy for daily use.
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Affiliation(s)
- Hanna Faber
- University Eye Hospital Center for Ophthalmology Eberhard Karls University Tuebingen Germany
| | - Dorothea Besch
- University Eye Hospital Center for Ophthalmology Eberhard Karls University Tuebingen Germany
| | | | - Hanna Eisenstein
- University Eye Hospital Center for Ophthalmology Eberhard Karls University Tuebingen Germany
| | - Johann Roider
- Department of Ophthalmology Christian‐Albrechts‐University of Kiel University Medical Center Kiel Germany
| | - Helmut Sachs
- Städtisches Klinikum Dresden Friedrichstadt Dresden Germany
| | - Florian Gekeler
- Department of Ophthalmology Klinikum Stuttgart Stuttgart Germany
| | - Eberhart Zrenner
- Institute for Ophthalmic Research Center for Ophthalmology Eberhard Karls University Tuebingen Germany
- Werner Reichardt Centre for Integrative Neuroscience Eberhard Karls University Tuebingen Tuebingen Germany
| | - Katarina Stingl
- University Eye Hospital Center for Ophthalmology Eberhard Karls University Tuebingen Germany
- Center for Rare Eye Diseases Eberhard Karls University Tuebingen Germany
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Choi KE, Anh VTQ, Seo HW, Kim N, Kim S, Kim SW. Ab-interno surgical technique for the implantation of a wireless subretinal prosthesis in mini-pigs. Sci Rep 2020; 10:18507. [PMID: 33116246 PMCID: PMC7595207 DOI: 10.1038/s41598-020-75579-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Accepted: 10/16/2020] [Indexed: 11/22/2022] Open
Abstract
We sought to describe the surgical techniques required in the ab-interno method to implant subretinal prostheses in mini-pigs and suggest tips to facilitate optimal outcomes. During vitrectomy, the use of valved trocar cannulas was essential to stabilize the detached retina and implanted chip. As a first step in retinal detachment, a 23-gauge cannula with very small amount of viscoelastic material was used to establish the retinal hole and promote retinal detachment. Then, balanced salt solution was applied to increase the retinal detachment and diathermy was used to make opening for subretinal prosthesis. For easy positioning of the subretinal prosthesis, a curved laser probe was adopted when handling the subretinal prosthesis under the retina. After surgery, the sclerotomy sites were tightly sutured to prevent silicone oil leakage. Without special equipment, such as a 41-gauge tip, retinal detachment could be induced easily, while the prosthesis was also successfully inserted and manipulated under the retina without an iatrogenic retinal tear. Two weeks after the operation, the oil fully occupied the intraocular volume without leakage. The subretinal prosthesis remained stable without complication. Understanding the principle of the ab-interno method and considering several tips for improving surgical access may help to enhance surgical success rates of subretinal prostheses implantation.
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Affiliation(s)
- Kwang-Eon Choi
- Department of Ophthalmology, Korea University College of Medicine, Seoul, South Korea
| | - Vu Thi Que Anh
- Department of Ophthalmology, Hanoi Medical University, Hanoi, Vietnam
| | - Hee Won Seo
- Department of Robotics Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, South Korea
| | - Namju Kim
- Department of Robotics Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, South Korea
| | - Sohee Kim
- Department of Robotics Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, South Korea.
| | - Seong-Woo Kim
- Department of Ophthalmology, Korea University College of Medicine, Seoul, South Korea.
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Yu ZH, Chen WJ, Liu X, Xia QY, Yang YN, Dong M, Liu JH, Guan HJ, Sun C, Feng FD, Shen QD. Folate-Modified Photoelectric Responsive Polymer Microarray as Bionic Artificial Retina to Restore Visual Function. ACS Appl Mater Interfaces 2020; 12:28759-28767. [PMID: 32478503 DOI: 10.1021/acsami.0c04058] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
A high-optical-resolution artificial retina system that accurately communicates with the optic nerve is the main challenge in the modern biological science and bionic field. Here, we developed a bionic artificial retina possessing phototransduction "cells" with measurements even smaller than that of the neural cells. Using the technique of micrometer processing, we constructed a pyramid-shape periodic microarray of a photoreceptor. Each "sensing cell" took advantage of polythiophene derivative/fullerene derivative (PCBM) as a photoelectric converter. Because folic acid played an essential role in eye growth, we particularly modified the polythiophene derivatives with folic acid tags. Therefore, the artificial retina could enlarge the contact area and even recognize the nerve cells to improve the consequence of nerve stimulation. We implanted the artificial retina into blinded rats' eyes. Electrophysiological analysis revealed its recovery of photosensitive function 3 months after surgery. Our work provides an innovative idea for fabricating a high-resolution bionic artificial retina system. It shows great potential in artificial intelligence and biomedicine.
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Affiliation(s)
- Zheng-Hang Yu
- Department of Polymer Science & Engineering and Key Laboratory of High Performance Polymer Materials & Technology of MOE, School of Chemistry & Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Wei-Jian Chen
- Department of Polymer Science & Engineering and Key Laboratory of High Performance Polymer Materials & Technology of MOE, School of Chemistry & Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Xi Liu
- Key Laboratory for Neuroregeneration of Jiangsu Province and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong 226001, China
- Eye Institute, Affiliated Hospital of Nantong University, Nantong 226001, China
| | - Qiu-Yu Xia
- Department of Polymer Science & Engineering and Key Laboratory of High Performance Polymer Materials & Technology of MOE, School of Chemistry & Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Yi-Nuo Yang
- Key Laboratory for Neuroregeneration of Jiangsu Province and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong 226001, China
- Eye Institute, Affiliated Hospital of Nantong University, Nantong 226001, China
| | - Mei Dong
- Department of Polymer Science & Engineering and Key Laboratory of High Performance Polymer Materials & Technology of MOE, School of Chemistry & Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Jia-Hao Liu
- Department of Polymer Science & Engineering and Key Laboratory of High Performance Polymer Materials & Technology of MOE, School of Chemistry & Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Huai-Jin Guan
- Key Laboratory for Neuroregeneration of Jiangsu Province and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong 226001, China
- Eye Institute, Affiliated Hospital of Nantong University, Nantong 226001, China
| | - Cheng Sun
- Key Laboratory for Neuroregeneration of Jiangsu Province and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong 226001, China
| | - Fu-De Feng
- Department of Polymer Science & Engineering and Key Laboratory of High Performance Polymer Materials & Technology of MOE, School of Chemistry & Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Qun-Dong Shen
- Department of Polymer Science & Engineering and Key Laboratory of High Performance Polymer Materials & Technology of MOE, School of Chemistry & Chemical Engineering, Nanjing University, Nanjing 210023, China
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Takhchidi KP, Kachalina GF, Takhchidi NK, Manoyan RA, Gliznitsa PV. A bionic eye: performance of the Argus II retinal prosthesis in low-vision and social rehabilitation of patients with end-stage retinitis pigmentosa. BRSMU 2019. [DOI: 10.24075/brsmu.2019.042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The death of outer retinal layers occurring in retinitis pigmentosa causes severe visual impairment and often leads to total blindness. Inner retinal layers are spared, though, which provides a possibility of inducing visual perception by direct electrical stimulation of intact retinal cells. This article presents clinical outcomes of two patients who were the first in Russia to have received the Argus II Retinal Prosthesis System. Both implantations were successful. No complications were reported throughout the entire follow-up period. Upon completing 3 rehabilitation sessions, the patients were able to navigate indoors and outdoors, locate small high-contrast objects, discern contours of large objects and people’s silhouettes.
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Affiliation(s)
- Kh. P. Takhchidi
- Pirogov Russian National Research Medical University, Moscow, Russia
| | - G. F. Kachalina
- Scientific Clinical Center of Otorhinolaryngology, FMBA of Russia, Moscow, Russia
| | - N. Kh. Takhchidi
- Scientific Clinical Center of Otorhinolaryngology, FMBA of Russia, Moscow, Russia
| | - R. A. Manoyan
- Scientific Clinical Center of Otorhinolaryngology, FMBA of Russia, Moscow, Russia
| | - P. V. Gliznitsa
- Pirogov Russian National Research Medical University, Moscow, Russia
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12
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Liu W, Liu M, Liu Y, Li S, Weng C, Fu Y, He J, Gong Y, Liu W, Zhao C, Yin ZQ. Validation and Safety of Visual Restoration by Ectopic Expression of Human Melanopsin in Retinal Ganglion Cells. Hum Gene Ther 2019; 30:714-726. [PMID: 30582371 DOI: 10.1089/hum.2018.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
To study whether ectopic human melanopsin (hMel) in retinal ganglion cells (RGCs) could restore the visual function in end-stage retinal degeneration, AAV2/8-CMV-hMel/FYP was injected into the intravitreal space of Royal College of Surgeons (RCS) rats. It was observed that ectopic hMel/yellow fluorescent protein (YFP) was dominantly expressed in the RGCs of the RCS rat retinae. At 30-45 days after administration of AAV2/8-CMV-hMel/FYP in RCS rats, the flash visual evoked potentials and behavioral results demonstrated that visual function was significantly improved compared to that in the control group, while no improvement in flash electroretinography was observed at this time point. To translate this potential therapeutic approach to the clinic, the safety of viral vectors in the retinae of normal macaques was then studied, and the expression profile of exogenous hMel with/without internal limiting membrane peeling was compared before viral vector administration. The data revealed that there was no significant difference in the number of RGCs containing exogenous hMel/YFP between the two groups. Whole-cell patch-clamp recordings demonstrated that the hMel/YFP-positive RGCs of the macaque retinae reacted to the intense light stimulation, generating inward currents and action potentials. This result confirms that the ectopic hMel expressed in RGCs is functional. Moreover, the introduction of AAV2/8-CMV-hMel/FYP does not cause detectable pathological effects. Thus, this study suggests that AAV2/8-CMV-hMel/FYP administration without internal limiting membrane peeling is safe and feasible for efficient transduction and provides therapeutic benefits to restore the visual function of patients suffering photoreceptor loss.
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Affiliation(s)
- Wenyi Liu
- 1 Southwest Hospital/Southwest Eye Hospital, Third Military Medical University, Chongqing, P.R. China; and Chongqing, P.R. China.,2 Key Lab of Visual Damage and Regeneration and Restoration of Chongqing, Chongqing, P.R. China
| | - Mingming Liu
- 1 Southwest Hospital/Southwest Eye Hospital, Third Military Medical University, Chongqing, P.R. China; and Chongqing, P.R. China.,2 Key Lab of Visual Damage and Regeneration and Restoration of Chongqing, Chongqing, P.R. China
| | - Yong Liu
- 1 Southwest Hospital/Southwest Eye Hospital, Third Military Medical University, Chongqing, P.R. China; and Chongqing, P.R. China.,2 Key Lab of Visual Damage and Regeneration and Restoration of Chongqing, Chongqing, P.R. China
| | - ShiYing Li
- 1 Southwest Hospital/Southwest Eye Hospital, Third Military Medical University, Chongqing, P.R. China; and Chongqing, P.R. China.,2 Key Lab of Visual Damage and Regeneration and Restoration of Chongqing, Chongqing, P.R. China
| | - Chuanhuang Weng
- 1 Southwest Hospital/Southwest Eye Hospital, Third Military Medical University, Chongqing, P.R. China; and Chongqing, P.R. China.,2 Key Lab of Visual Damage and Regeneration and Restoration of Chongqing, Chongqing, P.R. China
| | - Yan Fu
- 1 Southwest Hospital/Southwest Eye Hospital, Third Military Medical University, Chongqing, P.R. China; and Chongqing, P.R. China.,2 Key Lab of Visual Damage and Regeneration and Restoration of Chongqing, Chongqing, P.R. China
| | - Juncai He
- 1 Southwest Hospital/Southwest Eye Hospital, Third Military Medical University, Chongqing, P.R. China; and Chongqing, P.R. China.,2 Key Lab of Visual Damage and Regeneration and Restoration of Chongqing, Chongqing, P.R. China
| | - Yu Gong
- 1 Southwest Hospital/Southwest Eye Hospital, Third Military Medical University, Chongqing, P.R. China; and Chongqing, P.R. China.,2 Key Lab of Visual Damage and Regeneration and Restoration of Chongqing, Chongqing, P.R. China
| | - Weiping Liu
- 1 Southwest Hospital/Southwest Eye Hospital, Third Military Medical University, Chongqing, P.R. China; and Chongqing, P.R. China.,2 Key Lab of Visual Damage and Regeneration and Restoration of Chongqing, Chongqing, P.R. China
| | - CongJian Zhao
- 1 Southwest Hospital/Southwest Eye Hospital, Third Military Medical University, Chongqing, P.R. China; and Chongqing, P.R. China.,2 Key Lab of Visual Damage and Regeneration and Restoration of Chongqing, Chongqing, P.R. China
| | - Zheng Qin Yin
- 1 Southwest Hospital/Southwest Eye Hospital, Third Military Medical University, Chongqing, P.R. China; and Chongqing, P.R. China.,2 Key Lab of Visual Damage and Regeneration and Restoration of Chongqing, Chongqing, P.R. China
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13
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Weiland JD, Humayun MS, Gonzalez Calle A. The Development of Visual Prosthetic Devices to Restore Vision to the Blind. Neuromodulation 2018. [DOI: 10.1016/b978-0-12-805353-9.00101-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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14
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Eiber CD, Dokos S, Lovell NH, Suaning GJ. Multipolar Field Shaping in a Suprachoroidal Visual Prosthesis. IEEE Trans Neural Syst Rehabil Eng 2017; 25:2480-2487. [DOI: 10.1109/tnsre.2017.2730880] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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15
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Stingl K, Schippert R, Bartz-Schmidt KU, Besch D, Cottriall CL, Edwards TL, Gekeler F, Greppmaier U, Kiel K, Koitschev A, Kühlewein L, MacLaren RE, Ramsden JD, Roider J, Rothermel A, Sachs H, Schröder GS, Tode J, Troelenberg N, Zrenner E. Interim Results of a Multicenter Trial with the New Electronic Subretinal Implant Alpha AMS in 15 Patients Blind from Inherited Retinal Degenerations. Front Neurosci 2017; 11:445. [PMID: 28878616 PMCID: PMC5572402 DOI: 10.3389/fnins.2017.00445] [Citation(s) in RCA: 106] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Accepted: 07/20/2017] [Indexed: 11/13/2022] Open
Abstract
Purpose: We assessed the safety and efficacy of a technically advanced subretinal electronic implant, RETINA IMPLANT Alpha AMS, in end stage retinal degeneration in an interim analysis of two ongoing prospective clinical trials. The purpose of this article is to describe the interim functional results (efficacy). Methods: The subretinal visual prosthesis RETINA IMPLANT Alpha AMS (Retina Implant AG, Reutlingen, Germany) was implanted in 15 blind patients with hereditary retinal degenerations at four study sites with a follow-up period of 12 months (www.clinicaltrials.gov NCT01024803 and NCT02720640). Functional outcome measures included (1) screen-based standardized 2- or 4-alternative forced-choice (AFC) tests of light perception, light localization, grating detection (basic grating acuity (BaGA) test), and Landolt C-rings; (2) gray level discrimination; (3) performance during activities of daily living (ADL-table tasks). Results: Implant-mediated light perception was observed in 13/15 patients. During the observation period implant mediated localization of visual targets was possible in 13/15 patients. Correct grating detection was achieved for spatial frequencies of 0.1 cpd (cycles per degree) in 4/15; 0.33 cpd in 3/15; 0.66 cpd in 2/15; 1.0 cpd in 2/15 and 3.3 cpd in 1/15 patients. In two patients visual acuity (VA) assessed with Landolt C- rings was 20/546 and 20/1111. Of 6 possible gray levels on average 4.6 ± 0.8 (mean ± SD, n = 10) were discerned. Improvements (power ON vs. OFF) of ADL table tasks were measured in 13/15 patients. Overall, results were stable during the observation period. Serious adverse events (SAEs) were reported in 4 patients: 2 movements of the implant, readjusted in a second surgery; 4 conjunctival erosion/dehiscence, successfully treated; 1 pain event around the coil, successfully treated; 1 partial reduction of silicone oil tamponade leading to distorted vision (silicon oil successfully refilled). The majority of adverse events (AEs) were transient and mostly of mild to moderate intensity. Conclusions: Psychophysical and subjective data show that RETINA IMPLANT Alpha AMS is reliable, well tolerated and can restore limited visual functions in blind patients with degenerations of the outer retina. Compared with the previous implant Alpha IMS, longevity of the new implant Alpha AMS has been considerably improved. Alpha AMS has meanwhile been certified as a commercially available medical device, reimbursed in Germany by the public health system.
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Affiliation(s)
- Katarina Stingl
- Centre for Ophthalmology, University of TuebingenTuebingen, Germany
| | | | | | - Dorothea Besch
- Centre for Ophthalmology, University of TuebingenTuebingen, Germany
| | - Charles L Cottriall
- Nuffield Laboratory of Ophthalmology, Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, University of OxfordOxford, United Kingdom
| | - Thomas L Edwards
- Nuffield Laboratory of Ophthalmology, Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, University of OxfordOxford, United Kingdom
| | - Florian Gekeler
- Centre for Ophthalmology, University of TuebingenTuebingen, Germany.,Department of Ophthalmology, Katharinenhospital, Klinikum StuttgartStuttgart, Germany
| | | | - Katja Kiel
- Städtisches Klinikum Dresden Friedrichstadt, University Teaching HospitalDresden, Germany
| | - Assen Koitschev
- Division Pediatric Otorhinolaryngology and Otology - Olgahospital, Department of Otorhinolaryngology, Klinikum StuttgartStuttgart, Germany
| | - Laura Kühlewein
- Centre for Ophthalmology, University of TuebingenTuebingen, Germany
| | - Robert E MacLaren
- Nuffield Laboratory of Ophthalmology, Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, University of OxfordOxford, United Kingdom
| | - James D Ramsden
- Nuffield Laboratory of Ophthalmology, Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, University of OxfordOxford, United Kingdom
| | - Johann Roider
- Department of Ophthalmology, University of KielKiel, Germany
| | | | - Helmut Sachs
- Städtisches Klinikum Dresden Friedrichstadt, University Teaching HospitalDresden, Germany
| | | | - Jan Tode
- Department of Ophthalmology, University of KielKiel, Germany
| | | | - Eberhart Zrenner
- Centre for Ophthalmology, University of TuebingenTuebingen, Germany.,Werner Reichardt Centre for Integrative Neuroscience, University of TuebingenTuebingen, Germany
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16
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Cheng DL, Greenberg PB, Borton DA. Advances in Retinal Prosthetic Research: A Systematic Review of Engineering and Clinical Characteristics of Current Prosthetic Initiatives. Curr Eye Res 2017; 42:334-347. [PMID: 28362177 DOI: 10.1080/02713683.2016.1270326] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
PURPOSE To date, reviews of retinal prostheses have focused primarily on devices undergoing human trials in the Western Hemisphere and fail to capture significant advances in materials and engineering research in countries such as Japan and Korea, as well as projects in early stages of development. To address these gaps, this systematic review examines worldwide advances in retinal prosthetic research, evaluates engineering characteristics and clinical progress of contemporary device initiatives, and identifies potential directions for future research in the field of retinal prosthetics. METHODS A literature search using PubMed, Google Scholar, and IEEExplore was conducted following the PRISMA Guidelines for Systematic Review. Inclusion criteria were peer-reviewed papers demonstrating progress in human or animal trials and papers discussing the prosthetic engineering design. For each initiative, a description of the device, its engineering considerations, and recent clinical results were provided. RESULTS Ten prosthetic initiatives met our inclusion criteria and were organized by stimulation location. Of these initiatives, four have recently completed human trials, three are undergoing multi- or single-center human trials, and three are undergoing preclinical animal testing. Only the Argus II (FDA 2013, CE 2011) has obtained FDA approval for use in the United States; the Alpha-IMS (CE 2013) has achieved the highest visual acuity using a Landolt-C test to date and is the only device presently undergoing a multicenter clinical trial. CONCLUSION Several distinct approaches to retinal stimulation have been successful in eliciting visual precepts in animals and/or humans. However, many clinical needs are still not met and engineering challenges must be addressed before a retinal prosthesis with the capability to fully and safely restore functional vision can be realized.
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Affiliation(s)
- Derrick L Cheng
- a Alpert Medical School , Brown University , Providence , RI , USA
| | - Paul B Greenberg
- b Section of Ophthalmology , Providence VA Medical Center , Providence , RI , USA.,c Division of Ophthalmology, Alpert Medical School , Brown University , Providence , RI , USA
| | - David A Borton
- d School of Engineering , Brown University , Providence , RI , USA.,e Brown Institute for Brain Science , Brown University , Providence , RI , USA
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17
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Werginz P, Rattay F. The impact of calcium current reversal on neurotransmitter release in the electrically stimulated retina. J Neural Eng 2016; 13:046013. [DOI: 10.1088/1741-2560/13/4/046013] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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18
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Koitschev A, Stingl K, Bartz-Schmidt KU, Braun A, Gekeler F, Greppmaier U, Sachs H, Peters T, Wilhelm B, Zrenner E, Besch D. Extraocular Surgical Approach for Placement of Subretinal Implants in Blind Patients: Lessons from Cochlear-Implants. J Ophthalmol 2015; 2015:842518. [PMID: 26783453 DOI: 10.1155/2015/842518] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Revised: 11/11/2015] [Accepted: 11/16/2015] [Indexed: 11/29/2022] Open
Abstract
In hereditary retinal diseases photoreceptors progressively degenerate, often causing blindness without therapy being available. Newly developed subretinal implants can substitute functions of photoreceptors. Retina implant extraocular surgical technique relies strongly on cochlear-implant know-how. However, a completely new surgical approach providing safe handling of the photosensor array had to be developed. The Retina Implant Alpha IMS consisting of a subretinal microphotodiode array and cable linked to a cochlear-implant-like ceramic housing was introduced via a retroauricular incision through a subperiosteal tunnel above the zygoma into the orbit using a specially designed trocar. Implant housing was fixed in a bony bed within a tight subperiosteal pocket in all patients. Primary outcomes were patient short term safety as well as effectiveness. Nine patients participated in the first part of the multicenter trial and received the subretinal visual implant in one eye. In all cases microphotodiode array pull-through procedure and stable positioning were possible without affecting the device function. No intraoperative complications were encountered. The minimally invasive suprazygomatic tunneling technique for the sensor unit as well as a subperiosteal pocket fixation of the implant housing provides a safe extraocular implantation approach of a subretinal device with a transcutaneous extracorporeal power supply.
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19
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Ilmarinen T, Hiidenmaa H, Kööbi P, Nymark S, Sorkio A, Wang JH, Stanzel BV, Thieltges F, Alajuuma P, Oksala O, Kataja M, Uusitalo H, Skottman H. Ultrathin Polyimide Membrane as Cell Carrier for Subretinal Transplantation of Human Embryonic Stem Cell Derived Retinal Pigment Epithelium. PLoS One 2015; 10:e0143669. [PMID: 26606532 PMCID: PMC4659637 DOI: 10.1371/journal.pone.0143669] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Accepted: 11/06/2015] [Indexed: 12/11/2022] Open
Abstract
In this study, we investigated the suitability of ultrathin and porous polyimide (PI) membrane as a carrier for subretinal transplantation of human embryonic stem cell (hESC) -derived retinal pigment epithelial (RPE) cells in rabbits. The in vivo effects of hESC-RPE cells were analyzed by subretinal suspension injection into Royal College of Surgeons (RCS) rats. Rat eyes were analyzed with electroretinography (ERG) and histology. After analyzing the surface and permeability properties of PI, subretinal PI membrane transplantations with and without hESC-RPE were performed in rabbits. The rabbits were followed for three months and eyes analyzed with fundus photography, ERG, optical coherence tomography (OCT), and histology. Animals were immunosuppressed with cyclosporine the entire follow-up time. In dystrophic RCS rats, ERG and outer nuclear layer (ONL) thickness showed some rescue after hESC-RPE injection. Cells positive for human antigen were found in clusters under the retina 41 days post-injection but not anymore after 105 days. In rabbits, OCT showed good placement of the PI. However, there was loss of pigmentation on the hESC-RPE-PI over time. In the eyes with PI alone, no obvious signs of inflammation or retinal atrophy were observed. In the presence of hESC-RPE, mononuclear cell infiltration and retinal atrophy were observed around the membranes. The porous ultrathin PI membrane was well-tolerated in the subretinal space and is a promising scaffold for RPE transplantation. However, the rejection of the transplanted cells seems to be a major problem and the given immunosuppression was insufficient for reduction of xenograft induced inflammation.
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Affiliation(s)
- Tanja Ilmarinen
- BioMediTech, University of Tampere, Tampere, Finland
- * E-mail:
| | | | - Peeter Kööbi
- Department of Ophthalmology, SILK, University of Tampere and Tays Eye Center, Tampere, Finland
| | - Soile Nymark
- Department of Electronics and Communications Engineering and BioMediTech, Tampere University of Technology, Tampere, Finland
| | - Anni Sorkio
- BioMediTech, University of Tampere, Tampere, Finland
| | - Jing-Huan Wang
- Department of Ophthalmology, SILK, University of Tampere and Tays Eye Center, Tampere, Finland
| | | | | | | | | | | | - Hannu Uusitalo
- Department of Ophthalmology, SILK, University of Tampere and Tays Eye Center, Tampere, Finland
| | - Heli Skottman
- BioMediTech, University of Tampere, Tampere, Finland
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20
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Abstract
Navigating the world with visual impairments presents inconveniences and safety concerns. Although a traditional white cane is the most commonly used mobility aid due to its low cost and acceptable functionality, electronic traveling aids can provide more functionality as well as additional benefits. The Wearable Virtual Cane Network is an electronic traveling aid that utilizes ultrasound sonar technology to scan the surrounding environment for spatial information. The Wearable Virtual Cane Network is composed of four sensing nodes: one on each of the user's wrists, one on the waist, and one on the ankle. The Wearable Virtual Cane Network employs vibration and sound to communicate object proximity to the user. While conventional navigation devices are typically hand-held and bulky, the hands-free design of our prototype allows the user to perform other tasks while using the Wearable Virtual Cane Network. When the Wearable Virtual Cane Network prototype was tested for distance resolution and range detection limits at various displacements and compared with a traditional white cane, all participants performed significantly above the control bar (p < 4.3 × 10(-5), standard t-test) in distance estimation. Each sensor unit can detect an object with a surface area as small as 1 cm(2) (1 cm × 1 cm) located 70 cm away. Our results showed that the walking speed for an obstacle course was increased by 23% on average when subjects used the Wearable Virtual Cane Network rather than the white cane. The obstacle course experiment also shows that the use of the white cane in combination with the Wearable Virtual Cane Network can significantly improve navigation over using either the white cane or the Wearable Virtual Cane Network alone (p < 0.05, paired t-test).
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Affiliation(s)
- Yabiao Gao
- College of Engineering, The University of Georgia, Athens, GA, USA
| | - Rahul Chandrawanshi
- Department of Mechanical Engineering, Indian Institute of Technology (Banaras Hindu University), Varanasi, Varanasi, India
| | - Amy C Nau
- Korb & Associates, Boston, MA, USA Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Zion Tsz Ho Tse
- College of Engineering, The University of Georgia, Athens, GA, USA
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21
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Stingl K, Bartz-Schmidt KU, Besch D, Chee CK, Cottriall CL, Gekeler F, Groppe M, Jackson TL, MacLaren RE, Koitschev A, Kusnyerik A, Neffendorf J, Nemeth J, Naeem MAN, Peters T, Ramsden JD, Sachs H, Simpson A, Singh MS, Wilhelm B, Wong D, Zrenner E. Subretinal Visual Implant Alpha IMS--Clinical trial interim report. Vision Res 2015; 111:149-60. [PMID: 25812924 DOI: 10.1016/j.visres.2015.03.001] [Citation(s) in RCA: 224] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Revised: 02/18/2015] [Accepted: 03/02/2015] [Indexed: 11/27/2022]
Abstract
A subretinal visual implant (Alpha IMS, Retina Implant AG, Reutlingen, Germany) was implanted in 29 blind participants with outer retinal degeneration in an international multicenter clinical trial. Primary efficacy endpoints of the study protocol were a significant improvement of activities of daily living and mobility to be assessed by activities of daily living tasks, recognition tasks, mobility, or a combination thereof. Secondary efficacy endpoints were a significant improvement of visual acuity/light perception and/or object recognition (clinicaltrials.gov, NCT01024803). During up to 12 months observation time twenty-one participants (72%) reached the primary endpoints, of which thirteen participants (45%) reported restoration of visual function which they use in daily life. Additionally, detection, localization, and identification of objects were significantly better with the implant power switched on in the first 3 months. Twenty-five participants (86%) reached the secondary endpoints. Measurable grating acuity was up to 3.3 cycles per degree, visual acuities using standardized Landolt C-rings were 20/2000, 20/2000, 20/606 and 20/546. Maximal correct motion perception ranged from 3 to 35 degrees per second. These results show that subretinal implants can restore very-low-vision or low vision in blind (light perception or less) patients with end-stage hereditary retinal degenerations.
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Affiliation(s)
- Katarina Stingl
- Centre for Ophthalmology, University of Tübingen, Schleichstr. 12-16, 72076 Tübingen, Germany
| | | | - Dorothea Besch
- Centre for Ophthalmology, University of Tübingen, Schleichstr. 12-16, 72076 Tübingen, Germany
| | - Caroline K Chee
- Department of Ophthalmology, National University Health System, 1E Kent Ridge Road, Singapore 119228, Singapore
| | - Charles L Cottriall
- Oxford Eye Hospital and Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford OX3 9DU, United Kingdom
| | - Florian Gekeler
- Centre for Ophthalmology, University of Tübingen, Schleichstr. 12-16, 72076 Tübingen, Germany; Klinikum Stuttgart - Katharinenhospital, Eye Clinic, Kriegsbergstraße 60, 70174 Stuttgart, Germany(1)
| | - Markus Groppe
- Oxford Eye Hospital and Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford OX3 9DU, United Kingdom
| | - Timothy L Jackson
- King's College Hospital and King's College London, Denmark Hill, London SE5 9RS, United Kingdom
| | - Robert E MacLaren
- Oxford Eye Hospital and Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford OX3 9DU, United Kingdom
| | - Assen Koitschev
- Klinikum Stuttgart - Olgahospital, ORL-Department, Pediatric Otorhinolaryngology and Otology, Kriegsbergstr. 62, 70176 Stuttgart, Germany
| | - Akos Kusnyerik
- Department of Ophthalmology, Semmelweis University, Maria utca 39, H-1085 Budapest, Hungary
| | - James Neffendorf
- King's College Hospital and King's College London, Denmark Hill, London SE5 9RS, United Kingdom
| | - Janos Nemeth
- Department of Ophthalmology, Semmelweis University, Maria utca 39, H-1085 Budapest, Hungary
| | - Mohamed Adheem Naser Naeem
- Department of Ophthalmology, National University Health System, 1E Kent Ridge Road, Singapore 119228, Singapore
| | - Tobias Peters
- STZ Eyetrial, Center for Ophthalmology, University of Tübingen, Schleichstr. 12-16, 72076 Tübingen, Germany
| | - James D Ramsden
- Department of Otolaryngology, Oxford University Hospitals NHS Trust, Oxford OX3 9DU, United Kingdom
| | - Helmut Sachs
- Klinikum Dresden Friedrichstadt, Univ. Teaching Hospital, Eye Clinic, Friedrichstr. 41, 01067 Dresden, Germany
| | - Andrew Simpson
- King's College Hospital and King's College London, Denmark Hill, London SE5 9RS, United Kingdom
| | - Mandeep S Singh
- Department of Ophthalmology, National University Health System, 1E Kent Ridge Road, Singapore 119228, Singapore
| | - Barbara Wilhelm
- STZ Eyetrial, Center for Ophthalmology, University of Tübingen, Schleichstr. 12-16, 72076 Tübingen, Germany
| | - David Wong
- Li Ka Shing Faculty of Medicine, University of Hong Kong, 301 Block B, Cyberport 4, Hong Kong
| | - Eberhart Zrenner
- Werner Reichardt Centre for Integrative Neuroscience (CIN), University of Tübingen, Schleichstr. 12-16, 72076 Tübingen, Germany; Centre for Ophthalmology, University of Tübingen, Schleichstr. 12-16, 72076 Tübingen, Germany.
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22
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Matonti F, Roux S, Denis D, Picaud S, Chavane F. [Blindness and visual rehabilitation]. J Fr Ophtalmol 2015; 38:93-102. [PMID: 25595628 DOI: 10.1016/j.jfo.2014.06.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2014] [Revised: 06/23/2014] [Accepted: 06/30/2014] [Indexed: 10/24/2022]
Abstract
Blindness and visual impairment are a major public health problem all over the world and in all societies. A large amount of basic science and clinical research aims to rehabilitate patients and help them become more independent. Various methods are explored from cell and molecular therapy to prosthetic interfaces. We review the various treatment alternatives, describing their results and their limitations.
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Affiliation(s)
- F Matonti
- Service d'ophtalmologie, hôpital Nord, chemin de Bourrely, 13915 Marseille cedex 20, France; Équipe InViBe, institut de neurosciences de la Timone, UMR 7289 CNRS, Aix-Marseille université, 13402 Marseille cedex 20, France.
| | - S Roux
- Équipe InViBe, institut de neurosciences de la Timone, UMR 7289 CNRS, Aix-Marseille université, 13402 Marseille cedex 20, France
| | - D Denis
- Service d'ophtalmologie, hôpital Nord, chemin de Bourrely, 13915 Marseille cedex 20, France; Équipe InViBe, institut de neurosciences de la Timone, UMR 7289 CNRS, Aix-Marseille université, 13402 Marseille cedex 20, France
| | - S Picaud
- Inserm, U968, CNRS, UMR 7210, institut de la vision, UPMC université Paris 06, 75012 Paris, France
| | - F Chavane
- Équipe InViBe, institut de neurosciences de la Timone, UMR 7289 CNRS, Aix-Marseille université, 13402 Marseille cedex 20, France
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Leung RT, Nayagam DAX, Williams RA, Allen PJ, Salinas-La Rosa CM, Luu CD, Shivdasani MN, Ayton LN, Basa M, Yeoh J, Saunders AL, Shepherd RK, Williams CE. Safety and efficacy of explanting or replacing suprachoroidal electrode arrays in a feline model. Clin Exp Ophthalmol 2014; 43:247-58. [PMID: 25196241 DOI: 10.1111/ceo.12428] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Accepted: 08/24/2014] [Indexed: 11/26/2022]
Abstract
BACKGROUND A key requirement for retinal prostheses is the ability for safe removal or replacement. We examined whether suprachoroidal electrode arrays can be removed or replaced after implantation. METHODS Suprachoroidal electrode arrays were unilaterally implanted into 13 adult felines. After 1 month, arrays were surgically explanted (n = 6), replaced (n = 5) or undisturbed (n = 2). The retina was assessed periodically using fundus photography and optical coherence tomography. Three months after the initial implantation, the function of replaced or undisturbed arrays was assessed by measuring the responses of the visual cortex to retinal electrical stimulation. The histopathology of tissues surrounding the implant was examined. RESULTS Array explantation or replacement was successful in all cases. Fundus photography showed localized disruption to the tapetum lucidum near the implant's tip in seven subjects following implantation. Although optical coherence tomography showed localized retinal changes, there were no widespread statistically significant differences in the thickness of the retinal layers or choroid. The distance between the electrodes and retina increased after device replacement but returned to control values within eight weeks (P < 0.03). Staphylomas developed near the scleral wound in five animals after device explantation. Device replacement did not alter the cortical evoked potential threshold. Histopathology showed localized outer nuclear layer thinning, tapetal disruption and pseudo-rosette formation, but the overall retinal morphology was preserved. CONCLUSIONS It is feasible to remove or replace conformable medical grade silicone electrode arrays implanted suprachoroidally. The scleral wound requires careful closure to minimize the risk of staphylomas.
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Affiliation(s)
- Ronald T Leung
- Bionics Institute, Melbourne, Victoria, Australia; Department of Pathology, The University of Melbourne, Melbourne, Victoria, Australia
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Kitiratschky VBD, Stingl K, Wilhelm B, Peters T, Besch D, Sachs H, Gekeler F, Bartz-Schmidt KU, Zrenner E. Safety evaluation of "retina implant alpha IMS"--a prospective clinical trial. Graefes Arch Clin Exp Ophthalmol 2014; 253:381-7. [PMID: 25219982 DOI: 10.1007/s00417-014-2797-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2013] [Revised: 08/28/2014] [Accepted: 08/29/2014] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND To restore vision in patients with retinitis pigmentosa, several types of electronic devices have been developed to stimulate neurons at different levels along the visual pathway. Subretinal stimulation of the retina with the Retina Implant Alpha IMS (Retina Implant AG, Reutlingen, Germany) has been demonstrated to provide useful vision in daily life. Here we evaluated the safety of this device. METHODS An interventional, prospective, multi-center, single-arm study was conducted in patients with retinitis pigmentosa with the Retina Implant Alpha IMS. The results from the first nine patients of a single center regarding safety of the device are reported. Any untoward medical occurrence related or unrelated to the tested device was documented and evaluated. RESULTS Nine adult subjects were included in the study at the Tübingen site. Seventy-five adverse events occurred in total, and 53 affected the eye and its adnexa. Thirty-one ocular adverse events had a relationship to the implant that was classified as "certain" while 19 had a probable or possible relationship; three had no relationship to the implant. Thirty-nine ocular adverse events resolved without sequelae, two resolved with sequelae, 11 remained unresolved, and in one the status was unknown. The intensity of ocular adverse events was mild in the majority of cases (n = 45), while six were of moderate and two of severe intensity. There was no non-ocular adverse event with certain relationship to the device. One subject lost light perception (without light localization) in her study eye. CONCLUSIONS In conclusion, this prospective study, "Safety and Efficacy of Subretinal Implants for Partial Restoration of Vision in Blind Patients," shows that the Retina Implant Alpha IMS is an option for restoring vision using a subretinal stimulation device with a clinically acceptable safety profile.
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Abstract
Retinal prostheses aim at restoring visual perception in blind patients affected by retinal diseases leading to the loss of photoreceptors, such as age-related macular degeneration or retinitis pigmentosa. Recent clinical trials have demonstrated the feasibility of this approach for restoring useful vision. Despite a limited number of electrodes (60), and therefore of pixels, some patients were able to read words and to recognize high-contrast objects. Face recognition and independent locomotion in unknown urban environments imply technological breakthroughs to increase the number and density of electrodes. This review presents recent clinical results and discusses future solutions to answer the major technological challenges.
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Affiliation(s)
- Serge Picaud
- Inserm, U968, Institut de la Vision, 17, rue Moreau, 75012 Paris, France; Sorbonne Universités, Université Pierre et Marie Curie (Paris-6), UMR S968, Institut de la Vision, 17, rue Moreau, 75012 Paris, France; CNRS, UMR 7210, Institut de la Vision, 17, rue Moreau, 75012 Paris, France; Fondation Ophtalmologique Adolphe de Rothschild, 75019 Paris, France.
| | - José-Alain Sahel
- Inserm, U968, Institut de la Vision, 17, rue Moreau, 75012 Paris, France; Sorbonne Universités, Université Pierre et Marie Curie (Paris-6), UMR S968, Institut de la Vision, 17, rue Moreau, 75012 Paris, France; CNRS, UMR 7210, Institut de la Vision, 17, rue Moreau, 75012 Paris, France; Fondation Ophtalmologique Adolphe de Rothschild, 75019 Paris, France; Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, 75012 Paris, France; Institute of Ophthalmology, University College of London, London EC1V 9EL, United Kingdom; Académie des sciences, Institut de France, 23, quai de Conti, 75006 Paris, France
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Abstract
INTRODUCTION/BACKGROUND The Argus® II is the first retinal prosthesis approved for the treatment of patients blind from retinitis pigmentosa (RP), receiving CE (Conformité Européenne) marking in March 2011 and FDA approval in February 2013. Alpha-IMS followed closely and obtained CE marking in July 2013. Other devices are being developed, some of which are currently in clinical trials. SOURCES OF DATA A systematic literature search was conducted on PubMED, Google Scholar and IEEExplore. AREAS OF AGREEMENT Retinal prostheses play a part in restoring vision in blind RP patients providing stable, safe and long-term retinal stimulation. AREAS OF CONTROVERSY Objective improvement in visual function does not always translate into consistent improvement in the patient's quality of life. Controversy exists over the use of an external image-capturing device versus internally placed photodiode devices. GROWING POINTS The alpha-IMS, a photovoltaic-based retinal prosthesis recently obtained its CE marking in July 2013. AREAS TIMELY FOR DEVELOPING RESEARCH Improvement in retinal prosthetic vision depends on: (i) improving visual resolution, (ii) improving the visual field, (iii) developing an accurate neural code for image processing and (iv) improving the biocompatibility of the device to ensure longevity.
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Affiliation(s)
- Yvonne H-L Luo
- Biomedical Research Centre, National Institute of Health Research, Moorfields Eye Hospital NHS Foundation Trust, 162 City Road, London EC1V 2PD, UK
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Bendali A, Lorach H, Djilas M, Marre O, Bensoman R, Rousseau L, Lissorgues G, Scorsone E, Bergonzo P, Garrido JA, Sahel JA, Picaud S. [Restoring vision in blind patients following photoreceptor degeneration: clinical results and future challenges]. Biol Aujourdhui 2013; 207:123-32. [PMID: 24103342 DOI: 10.1051/jbio/2013008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Indexed: 11/15/2022]
Abstract
Retinal prostheses aim at restoring vision in patients blind from photoreceptor degeneration by electrically stimulating the residual retinal tissue. Currently, the most efficient implants are either inserted in the subretinal space or on the vitreal side of the retina (epi-retinal). Although the residual tissue can partly degenerate, it was shown that acute stimulation of residual neurones can induce visual percepts. Recently, a clinical trial with the epiretinal Argus2 device (60 electrodes) from the company 2nd Sight enabled most patients to orient and find light targets, some even reading words. This device has received a CE mark. Surprisingly, when the subretinal implant from the company Retina Implant AG displaying many more electrodes (1500 electrodes) was evaluated in clinical trials, the patient visual performances were fairly similar. The restored visual performances of the patients demonstrate that blind patients can recover some visual function when their residual retina is properly stimulated. However, the resolution is not yet sufficient to perform complex tasks such as autonomous locomotion, face identification or text reading. Several challenges remain to generate an increase in pixel density corresponding to the increase in electrode number and density. These challenges include the stimulation modality, the tissue/implant interface design, the electrode materials, and the visual information encoder. This review will discuss these great challenges after introducing the major clinical results.
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Affiliation(s)
- Amel Bendali
- INSERM, U968, Institut de la Vision, 75012 Paris, France - UPMC Université Paris 06, UMR S968, Institut de la Vision, 75012 Paris, France - CNRS, UMR 7210, Institut de la Vision, 75012 Paris, France
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Abstract
OBJECTIVE We present a holographic near-the-eye display system enabling optical approaches for sight restoration to the blind, such as photovoltaic retinal prosthesis, optogenetic and other photoactivation techniques. We compare it with conventional liquid crystal displays (LCD) or digital light processing (DLP)-based displays in terms of image quality, field of view, optical efficiency and safety. APPROACH We detail the optical configuration of the holographic display system and its characterization using a phase-only spatial light modulator. MAIN RESULTS We describe approaches to controlling the zero diffraction order and speckle related issues in holographic display systems and assess the image quality of such systems. We show that holographic techniques offer significant advantages in terms of peak irradiance and power efficiency, and enable designs that are inherently safer than LCD or DLP-based systems. We demonstrate the performance of our holographic display system in the assessment of cortical response to alternating gratings projected onto the retinas of rats. SIGNIFICANCE We address the issues associated with the design of high brightness, near-the-eye display systems and propose solutions to the efficiency and safety challenges with an optical design which could be miniaturized and mounted onto goggles.
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Affiliation(s)
- G A Goetz
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305, USA
- Department of Electrical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Y Mandel
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305, USA
- Department of Ophthalmology, Stanford University, Stanford, CA 94305, USA
| | - R Manivanh
- Department of Ophthalmology, Stanford University, Stanford, CA 94305, USA
| | - D V Palanker
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305, USA
- Department of Ophthalmology, Stanford University, Stanford, CA 94305, USA
| | - T Čižmár
- School of Medicine, University of St Andrews, North Haugh, KY16 9TF, UK
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Sirova M, Vlierberghe SV, Matyasova V, Rossmann P, Schacht E, Dubruel P, Rihova B. Immunocompatibility evaluation of hydrogel-coated polyimide implants for applications in regenerative medicine. J Biomed Mater Res A 2013; 102:1982-90. [DOI: 10.1002/jbm.a.34873] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Revised: 07/02/2013] [Accepted: 07/08/2013] [Indexed: 11/08/2022]
Affiliation(s)
- Milada Sirova
- Division of Immunology and Gnotobiology, Institute of Microbiology; Academy of Sciences of the Czech Republic; v.v.i., Videnska 1083, 142 20 Prague 4 Czech Republic
| | - Sandra Van Vlierberghe
- Polymer Chemistry and Biomaterials Research Group; Ghent University; Krijgslaan 281 S4-bis 9000 Ghent Belgium
| | - Veronika Matyasova
- Division of Immunology and Gnotobiology, Institute of Microbiology; Academy of Sciences of the Czech Republic; v.v.i., Videnska 1083, 142 20 Prague 4 Czech Republic
| | - Pavel Rossmann
- Division of Immunology and Gnotobiology, Institute of Microbiology; Academy of Sciences of the Czech Republic; v.v.i., Videnska 1083, 142 20 Prague 4 Czech Republic
| | - Etienne Schacht
- Polymer Chemistry and Biomaterials Research Group; Ghent University; Krijgslaan 281 S4-bis 9000 Ghent Belgium
| | - Peter Dubruel
- Polymer Chemistry and Biomaterials Research Group; Ghent University; Krijgslaan 281 S4-bis 9000 Ghent Belgium
| | - Blanka Rihova
- Division of Immunology and Gnotobiology, Institute of Microbiology; Academy of Sciences of the Czech Republic; v.v.i., Videnska 1083, 142 20 Prague 4 Czech Republic
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Abstract
PURPOSE To highlight recent innovations in the medical and surgical treatment of retinal disease. DESIGN Retrospective literature review. METHODS The peer-reviewed, published (during 2012) English literature was searched using the Medline database. Articles deemed relevant were selected and highlighted. RESULTS A number of important innovations in the treatment of retinal disease have occurred during the past year. We review developments in regenerative medicine (e.g., retinal prosthesis, optogenetics, cell-based therapy), diagnostics (e.g., swept source optical coherence tomography [OCT], intraoperative OCT, multimodal imaging), surgical innovations (e.g., chemical vitreolysis with ocriplasmin, 27-gauge vitrectomy), and pharmacological therapy of retinal vascular disease (e.g., use of ranibizumab and aflibercept in the treatment of macular edema associated with diabetic retinopathy and retinal vein occlusion). CONCLUSIONS Many important innovations in regenerative medicine, diagnostic and surgical instrumentation, and pharmacological therapy for retinal vascular disease have occurred during the past year. In view of the number of agents in early phase clinical trials (e.g., treatments for dry age-related macular degeneration) as well as technologies under development (e.g., microrobots for vitreous surgery), this trend will continue.
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Affiliation(s)
- Neelakshi Bhagat
- From the Institute of Ophthalmology and Visual Science, New Jersey Medical School, Doctors Office Center, Newark, NJ
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32
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Dorn JD, Ahuja AK, Caspi A, da Cruz L, Dagnelie G, Sahel JA, Greenberg RJ, McMahon MJ. The Detection of Motion by Blind Subjects With the Epiretinal 60-Electrode (Argus II) Retinal Prosthesis. JAMA Ophthalmol 2013; 131:183-9. [PMID: 23544203 DOI: 10.1001/2013.jamaophthalmol.221] [Citation(s) in RCA: 136] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
OBJECTIVE To investigate the ability of 28 blind subjects implanted with a 60-electrode Argus II (Second Sight Medical Products Inc) retinal prosthesis system to detect the direction of a moving object. METHODS Blind subjects (bare light perception or worse in both eyes) with retinitis pigmentosa were implanted with the Argus II prosthesis as part of a phase 1/2 feasibility study at multiple clinical sites worldwide. The experiment measured their ability to detect the direction of motion of a high-contrast moving bar on a flatscreen monitor in 3 conditions: with the prosthesis system on and a 1-to-1 mapping of spatial information, with the system off, and with the system on but with randomly scrambled spatial information. RESULTS Fifteen subjects (54%) were able to perform the task significantly better with their prosthesis system than they were with their residual vision, 2 subjects had significantly better performance with their residual vision, and no difference was found for 11 subjects. Of the 15 better-performing subjects, 11 were available for follow-up testing, and 10 of them had significantly better performance with normal rather than with scrambled spatial information. CONCLUSIONS This work demonstrates that blind subjects implanted with the Argus II retinal prosthesis were able to perform a motion detection task they could not do with their native vision, confirming that electrical stimulation of the retina provides spatial information from synchronized activation of multiple electrodes. TRIAL REGISTRATION clinicaltrials.gov Identifier:NCT00407602
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Affiliation(s)
- Jessy D Dorn
- Second Sight Medical Products, Sylmar, CA 91342, USA.
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33
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Stingl K, Bartz-Schmidt KU, Besch D, Braun A, Bruckmann A, Gekeler F, Greppmaier U, Hipp S, Hörtdörfer G, Kernstock C, Koitschev A, Kusnyerik A, Sachs H, Schatz A, Stingl KT, Peters T, Wilhelm B, Zrenner E. Artificial vision with wirelessly powered subretinal electronic implant alpha-IMS. Proc Biol Sci 2013; 280:20130077. [PMID: 23427175 PMCID: PMC3619489 DOI: 10.1098/rspb.2013.0077] [Citation(s) in RCA: 229] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
This study aims at substituting the essential functions of photoreceptors in patients who are blind owing to untreatable forms of hereditary retinal degenerations. A microelectronic neuroprosthetic device, powered via transdermal inductive transmission, carrying 1500 independent microphotodiode-amplifier-electrode elements on a 9 mm2 chip, was subretinally implanted in nine blind patients. Light perception (8/9), light localization (7/9), motion detection (5/9, angular speed up to 35 deg s−1), grating acuity measurement (6/9, up to 3.3 cycles per degree) and visual acuity measurement with Landolt C-rings (2/9) up to Snellen visual acuity of 20/546 (corresponding to decimal 0.037 or corresponding to 1.43 logMAR (minimum angle of resolution)) were restored via the subretinal implant. Additionally, the identification, localization and discrimination of objects improved significantly (n = 8; p < 0.05 for each subtest) in repeated tests over a nine-month period. Three subjects were able to read letters spontaneously and one subject was able to read letters after training in an alternative-force choice test. Five subjects reported implant-mediated visual perceptions in daily life within a field of 15° of visual angle. Control tests were performed each time with the implant's power source switched off. These data show that subretinal implants can restore visual functions that are useful for daily life.
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Affiliation(s)
- Katarina Stingl
- Centre for Ophthalmology, University of Tübingen, Schleichstraße 12-16, Tübingen, Germany
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da Cruz L, Coley BF, Dorn J, Merlini F, Filley E, Christopher P, Chen FK, Wuyyuru V, Sahel J, Stanga P, Humayun M, Greenberg RJ, Dagnelie G. The Argus II epiretinal prosthesis system allows letter and word reading and long-term function in patients with profound vision loss. Br J Ophthalmol 2013; 97:632-6. [PMID: 23426738 PMCID: PMC3632967 DOI: 10.1136/bjophthalmol-2012-301525] [Citation(s) in RCA: 207] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND Retinal prosthesis systems (RPS) are a novel treatment for profound vision loss in outer retinal dystrophies. Ideal prostheses would offer stable, long-term retinal stimulation and reproducible spatial resolution in a portable form appropriate for daily life. METHODS We report a prospective, internally controlled, multicentre trial of the Argus II system. Twenty-eight subjects with light perception vision received a retinal implant. Controlled, closed-group, forced-choice letter identification, and, open-choice two-, three- and four-letter word identification tests were carried out. RESULTS The mean±SD percentage correct letter identification for 21 subjects tested were: letters L, T, E, J, F, H, I, U, 72.3±24.6% system on and 17.7±12.9% system off; letters A, Z, Q, V, N, W, O, C, D, M, 55.0±27.4% system on and 11.8%±10.7% system off, and letters K, R, G, X, B, Y, S, P, 51.7±28.9% system on and 15.3±7.4% system off. (p<0.001 for all groups). A subgroup of six subjects was able to consistently read letters of reduced size, the smallest measuring 0.9 cm (1.7°) at 30 cm, and four subjects correctly identify unrehearsed two-, three- and four-letter words. Average implant duration was 19.9 months. CONCLUSIONS Multiple blind subjects fitted with the Argus II system consistently identified letters and words using the device, indicating reproducible spatial resolution. This, in combination with stable, long-term function, represents significant progress in the evolution of artificial sight.
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Affiliation(s)
- Lyndon da Cruz
- NIHR Biomedical Research Centre for Ophthalmology, Moorfields Eye Hospital, 162 City Road, London EC1V 2PD, UK.
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Stingl K, Gekeler F, Bartz-Schmidt KU, Kögel A, Zrenner E, Gelisken F. Fluorescein Angiographic Findings in Eyes of Patients with a Subretinal Electronic Implant. Curr Eye Res 2013; 38:588-96. [DOI: 10.3109/02713683.2013.767349] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Humayun MS, Fernandes RAB, Weiland JD. Artificial Vision. Retina 2013. [DOI: 10.1016/b978-1-4557-0737-9.00126-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Humayun MS, Rowley AP, Whalen JJ, Weiland JD, Tanguay AR. The Development of a Retinal Prosthesis: A Significant Biomaterials Challenge. Biomater Sci 2013. [DOI: 10.1016/b978-0-08-087780-8.00081-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Mathieson K, Moodie AR, Grant E, Morrison JD. Development and evaluation of thin-film flexible microelectrode arrays for retinal stimulation and recording. J Med Eng Technol 2012; 37:79-85. [PMID: 23249248 DOI: 10.3109/03091902.2012.719995] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
We have described the development of a flexible microelectrode array with potential applications in the large scale recording of neural signals and in focal electrical stimulation for use as a prosthetic implant in degenerative retinal diseases. The array under test consisted of 61 platinum electrodes of 5 µm diameter with 60 µm spacing connected by 8 µm wide gold tracks encased in a flexible polyimide substrate of 15 µm thickness from which recordings were taken from 16 electrodes. The device was tested on an exposed frog eyecup preparation which is characterized by small retinal ganglion cells of similar dimensions to those present in the human retina. The responses of these cells evoked by photic stimulation consisted of trains of action potentials of high signal-to noise ratio at each of the recording sites. Delivery of cathodal constant voltage pulses and constant current pulses to specific electrodes in the array led to the generation of action potentials in adjacent electrodes, implying that retinal ganglion cells in the proximity had been stimulated. Since prolonged stimulation with supra-threshold voltages impaired neither electrode structure nor retinal function, these results provide a sound basis for scaling up the number of array electrodes to deliver focal electrical pulses to the retina, as would be required by a viable epiretinal prosthesis.
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Affiliation(s)
- K Mathieson
- Department of Physics and Astronomy, University of Glasgow, Glasgow, Scotland
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Peters T, Klingberg S, Zrenner E, Wilhelm B. Emotional wellbeing of blind patients in a pilot trial with subretinal implants. Graefes Arch Clin Exp Ophthalmol 2012. [DOI: 10.1007/s00417-012-2210-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
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Stingl K, Bach M, Bartz-Schmidt KU, Braun A, Bruckmann A, Gekeler F, Greppmaier U, Hörtdörfer G, Kusnyerik A, Peters T, Wilhelm B, Wilke R, Zrenner E. Safety and efficacy of subretinal visual implants in humans: methodological aspects. Clin Exp Optom 2012; 96:4-13. [PMID: 23173814 DOI: 10.1111/j.1444-0938.2012.00816.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2012] [Revised: 07/24/2012] [Accepted: 08/07/2012] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND Replacing the function of visual pathway neurons by electronic implants is a novel approach presently explored by various groups in basic research and clinical trials. The novelty raises unexplored methodological aspects of clinical trial design that may require adaptation and validation. METHODS We present procedures of efficacy and safety testing for subretinal visual implants in humans, as developed during our pilot trial 2005 to 2009 and multi-centre clinical trial since 2010. RESULTS Planning such a trial requires appropriate inclusion and exclusion criteria. For subretinal electronic visual implants, patients with photoreceptor degeneration are the target patient group, whereas presence of additional diseases affecting clear optic media or the visual pathway must be excluded. Because sham surgery is not possible, a masked study design with implant power ON versus OFF is necessary. Prior to the efficacy testing by psychophysical tests, the implant's technical characteristics have to be controlled via electroretinography (ERG). Moreover the testing methods require adaptation to the particular technology. We recommend standardised tasks first to determine the light perception thresholds, light localisation and movement detection, followed by grating acuity and vision acuity test via Landolt C rings. A laboratory setup for assessing essential activities of daily living is presented. Subjective visual experiences with the implant in a natural environment, as well as questionnaires and psychological counselling are further important aspects. CONCLUSIONS A clinical trial protocol for artificial vision in humans, which leads a patient from blindness to the state of very low vision is a challenge and cannot be defined completely prior to the study. Available tests of visual function may not be sufficiently suited for efficacy testing of artificial vision devices. A protocol based on experience with subretinal visual implants in 22 patients is presented that has been found adequate to monitor safety and efficacy.
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Affiliation(s)
- Katarina Stingl
- Center for Ophthalmology, University of Tübingen, Tübingen, Germany.
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Subrizi A, Hiidenmaa H, Ilmarinen T, Nymark S, Dubruel P, Uusitalo H, Yliperttula M, Urtti A, Skottman H. Generation of hESC-derived retinal pigment epithelium on biopolymer coated polyimide membranes. Biomaterials 2012; 33:8047-54. [DOI: 10.1016/j.biomaterials.2012.07.033] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Accepted: 07/15/2012] [Indexed: 12/29/2022]
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Stingl K, Bartz-Schmidt KU, Besch D, Gekeler F, Greppmaier U, Hörtdörfer G, Koitschev A, Peters T, Sachs H, Wilhelm B, Zrenner E. [What can blind patients see in daily life with the subretinal Alpha IMS implant? Current overview from the clinical trial in Tübingen]. Ophthalmologe 2012; 109:136-41. [PMID: 22350550 DOI: 10.1007/s00347-011-2479-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
The subretinal visual implant is a scientific research approach to restore partial vision in end-stage hereditary retinal diseases by replacing the function of the degenerated photoreceptors by microelectronic chips. In a clinical trial in Tübingen these implants were tested on voluntary blind patients. By using the implants in daily living the patients reported valuable visual information. The subretinal microchip mediates subjectively useful visual information in near as well as in distant vision.
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Affiliation(s)
- K Stingl
- Department für Augenheilkunde, Universität Tübingen, Schleichstr. 12-16, 72076, Tübingen, Deutschland.
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Abstract
The nervous system communicates in a language of electrical activities. The motivation to replace function lost through injury or disease through electrical prostheses has gained traction through steady advances in basic and translational science addressing the interface between electrical prostheses and the nervous system. Recent experiments suggest that electrical activity, signaling through specific molecular pathways, promotes neuronal survival and regeneration. Such data suggests that electrical prostheses, in addition to replacing lost function, may slow underlying degenerative disease or induce regenerative response. Here we review these data with a focus on retinal neurons, and discuss current efforts to translate this effect of electrical activity into clinically applicable treatments.
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Affiliation(s)
- Jeffrey L Goldberg
- Bascom Palmer Eye Institute and Interdisciplinary Stem Cell Institute, University of Miami Miller School of Medicine, Miami, FL 33136, United States.
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Khraiche ML, Lo Y, Wang D, Cauwenberghs G, Freeman W, Silva GA. Ultra-high photosensitivity silicon nanophotonics for retinal prosthesis: electrical characteristics. Annu Int Conf IEEE Eng Med Biol Soc 2012; 2011:2933-6. [PMID: 22254955 DOI: 10.1109/iembs.2011.6090807] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Retinal degenerative diseases such as age related macular degeneration (AMD) and retinitis pigmentosa (RP), lead to the loss of the photoreceptor cells rendering the retina incapable of detecting light. Several engineering approaches have aimed at replacing the function of the photoreceptors by detecting light via an external camera or photodiodes and electrically stimulating the remaining retinal tissue to restore vision. These devices rely heavily on off-device processing to solve the computational challenge of matching the performance of the PRs. In this work, we present a unique ultra-high sensitivity photodetector technology with light sensitivity, signal amplification, light adaptation that shows signal transduction performance approaching those of the rods and cones in the mammalian retina. In addition, the technology offers nanoscale control over photodetectors topography with the potential to reproduce the visual acuity of the natural retina. This technology promises to drastically reduce the foot print, power consumption and computational needs of the current retinal prothesis, while reproducing high resolution vision.
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Affiliation(s)
- Massoud L Khraiche
- Department of Bioengineering, University of California, San Diego, CA, USA
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Mathieson K, Loudin J, Goetz G, Huie P, Wang L, Kamins TI, Galambos L, Smith R, Harris JS, Sher A, Palanker D. Photovoltaic Retinal Prosthesis with High Pixel Density. Nat Photonics 2012; 6:391-397. [PMID: 23049619 PMCID: PMC3462820 DOI: 10.1038/nphoton.2012.104] [Citation(s) in RCA: 239] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2012] [Accepted: 04/04/2012] [Indexed: 05/21/2023]
Abstract
Retinal degenerative diseases lead to blindness due to loss of the "image capturing" photoreceptors, while neurons in the "image processing" inner retinal layers are relatively well preserved. Electronic retinal prostheses seek to restore sight by electrically stimulating surviving neurons. Most implants are powered through inductive coils, requiring complex surgical methods to implant the coil-decoder-cable-array systems, which deliver energy to stimulating electrodes via intraocular cables. We present a photovoltaic subretinal prosthesis, in which silicon photodiodes in each pixel receive power and data directly through pulsed near-infrared illumination and electrically stimulate neurons. Stimulation was produced in normal and degenerate rat retinas, with pulse durations from 0.5 to 4 ms, and threshold peak irradiances from 0.2 to 10 mW/mm(2), two orders of magnitude below the ocular safety limit. Neural responses were elicited by illuminating a single 70 μm bipolar pixel, demonstrating the possibility of a fully-integrated photovoltaic retinal prosthesis with high pixel density.
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Affiliation(s)
- Keith Mathieson
- Hansen Experimental Physics Laboratory, Stanford University ; Santa Cruz Institute for Particle Physics, UC Santa Cruz
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Fernandes RA, Diniz B, Ribeiro R, Humayun M. Artificial vision through neuronal stimulation. Neurosci Lett 2012; 519:122-8. [PMID: 22342306 DOI: 10.1016/j.neulet.2012.01.063] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2011] [Accepted: 01/25/2012] [Indexed: 11/23/2022]
Abstract
INTRODUCTION The term visual prosthesis refers to any device capable of eliciting visual percepts in an individual through electrical stimulation of any part of the visual system. BACKGROUND Blindness can be due to eye pathology or due to damage of the lateral geniculate or visual cortex. Eye pathology other than diseases that affect the cornea and lens are numerous and some of the leading causes are diabetic retinopathy, age-related macular degeneration, retinal detachment, glaucoma, and retinal vascular occlusions. The visual prosthesis can be divided into non-retinal and retinal approaches. Non-retinal approaches include cortical and optic nerve prosthesis. Retinal approaches are aimed at eye pathologies in which at least part of the optic nerve remains intact whereas when the optic nerve is nearly completely damaged and/or the eye itself is disfigured or degenerated then a non-retinal approach is warranted. The retinal prosthesis can be placed on the surface of the retina, in the subretinal space or in the suprachoroidal space. RESULTS Several independent groups related variable degrees of success in promoting visual sensations through electrical stimulation of the visual system. Every technique, equipment and anatomical target has its advantages and disadvantages, and the biological/electrical-mechanical interface is still the aspect of the research towards a chronic, long term, reliable biomimetic implant. CONCLUSIONS The visual prostheses have achieved significant developments in recent years. We see continued improvement in visual acuity with increasing number and density of electrodes. Even though the visual acuity is still poor relative to normal vision, these subjects can read letters using their implants. Perhaps more importantly, blind patients can use these devices for mobility and orientation.
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Weiland JD, Cho AK, Humayun MS. Retinal prostheses: current clinical results and future needs. Ophthalmology 2011; 118:2227-37. [PMID: 22047893 DOI: 10.1016/j.ophtha.2011.08.042] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2010] [Revised: 08/26/2011] [Accepted: 08/26/2011] [Indexed: 10/15/2022] Open
Abstract
UNLABELLED Degenerative diseases such as age-related macular degeneration (AMD) and retinitis pigmentosa (RP) primarily affect the photoreceptors, ultimately resulting in significant loss of vision. Retinal prostheses aim to elicit neural activity in the remaining retinal cells by detecting and converting light into electrical stimuli that can then be delivered to the retina. The concept of visual prostheses has existed for more than 50 years and recent progress shows promise, yet much remains to be understood about how the visual system will respond to artificial input after years of blindness that necessitate this type of prosthesis. This review focuses on 3 major areas: the histopathologic features of human retina affected by AMD and RP, current results from clinical trials, and challenges to overcome for continued improvement of retinal prostheses. FINANCIAL DISCLOSURE(S) Proprietary or commercial disclosures may be found after the references.
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Affiliation(s)
- James D Weiland
- Doheny Eye Institute, Department of Ophthalmology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
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Abstract
Clinical laboratories are strong, integral partners in personalized health care. Laboratory databases hold a vast amount of data on human phenotypes, genotypes, biomarkers, progression of disease, and response to therapy. These structured and unstructured free text data are critical for patient care and a resource for personalized medicine and translational research. Laboratory data are integrated into many electronic medical records that provide "summary reports" and "trending" to visualize longitudinal patient data. Recent advances in ophthalmology such as gene therapy, cell therapy using stem cells, and also retinal prosthesis explore the potential of translational research marking a new era in research into the diagnosis and treatment of eye diseases.
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Affiliation(s)
- Rubens Camargo Siqueira
- Rubens Siqueira Research Center, São José do Rio Preto, São Paulo, Brazil
- Retina and Vitreous Section, Department of Ophthalmology, School of Medicine of Ribeirão Preto, University of São Paulo, Brazil
| | - Rodrigo Jorge
- Retina and Vitreous Section, Department of Ophthalmology, School of Medicine of Ribeirão Preto, University of São Paulo, Brazil
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Abstract
Photodiode circuits show promise for the development of high-resolution retinal prostheses. While several of these systems have been constructed and some even implanted in humans, existing descriptions of the complex optoelectronic interaction between light, photodiode, and the electrode/electrolyte load are limited. This study examines this interaction in depth with theoretical calculations and experimental measurements. Actively biased photoconductive and passive photovoltaic circuits are investigated, with the photovoltaic circuits consisting of one or more diodes connected in series, and the photoconductive circuits consisting of a single diode in series with a pulsed bias voltage. Circuit behavior and charge injection levels were markedly different for platinum and sputtered iridium-oxide film (SIROF) electrodes. Photovoltaic circuits were able to deliver 0.038 mC/cm(2) (0.75 nC/phase) per photodiode with 50- μm platinum electrodes, and 0.54-mC/cm(2) (11 nC/phase) per photodiode with 50-μ m SIROF electrodes driven with 0.5-ms pulses of light at 25 Hz. The same pulses applied to photoconductive circuits with the same electrodes were able to deliver charge injections as high as 0.38 and 7.6 mC/cm(2) (7.5 and 150 nC/phase), respectively. We demonstrate photovoltaic stimulation of rabbit retina in-vitro, with 0.5-ms pulses of 905-nm light using peak irradiance of 1 mW/mm(2). Based on the experimental data, we derive electrochemical and optical safety limits for pixel density and charge injection in various circuits. While photoconductive circuits offer smaller pixels, photovoltaic systems do not require an external bias voltage. Both classes of circuits show promise for the development of high-resolution optoelectronic retinal prostheses.
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Laube T, Brockmann C, Roessler G, Walter P, Krueger C, Goertz M, Klauke S, Bornfeld N. Development of surgical techniques for implantation of a wireless intraocular epiretinal retina implant in Göttingen minipigs. Graefes Arch Clin Exp Ophthalmol 2012; 250:51-9. [PMID: 21861087 DOI: 10.1007/s00417-011-1756-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2010] [Revised: 05/10/2011] [Accepted: 07/28/2011] [Indexed: 10/17/2022] Open
Abstract
BACKGROUND The aim of this study was to develop surgical methods for the implantation of a wireless intraocular epiretinal retina implant (EPI RET3) in Göttingen minipigs. This animal model resembles closely the anatomical conditions in humans, and is thus suitable for investigating the EPI RET3 implant as designed for the application in humans. METHODS Phacoemulsification and vitrectomy was performed on the right eye of 16 Göttingen minipigs under general anesthesia. The implants, consisting of a receiver module and an electrode array connected via a flexible micro cable, were inserted through a corneoscleral incision. The receiver module was placed into the sulcus ciliaris and the electrode array was fixed onto the retina temporal to the optic disc with a retinal tack. Minipigs were monitored for intra- and postoperative ocular complications. Follow-up times were 3 (seven minipigs) and 12 weeks (nine minipigs). RESULTS Implantation was successfully performed in all 16 minipigs. The complete implantation surgery required on average 2 hours. Intraoperative findings were a minor hemorrhage of the anterior chamber angle in two eyes, one minor iris hemorrhage, and one minor punctiform retinal hemorrhage, which were all reversible. Postoperatively, the corneoscleral incision showed good wound healing in all eyes. Intraocular reactions included mainly fibrin exudation (six eyes) and formation of iris synechiae with the receiver module of the implants (three eyes). CONCLUSIONS The performed implantation procedures of the intraocular EPI RET3 implant are feasible and reproducible within an acceptable surgical time. The development of inflammatory responses is a specific predisposition of the minipig following any intraocular intervention; nevertheless, the surgical techniques should be further improved to minimize procedure-related reactions. Our results provide a step towards the application of the EPI RET3 system in clinical studies.
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