Chronic electrical stimulation with a suprachoroidal retinal prosthesis: a preclinical safety and efficacy study
To assess the safety and efficacy of chronic electrical stimulation of the retina with a suprachoroidal visual prosthesis. Seven normally-sighted feline subjects were implanted for 96-143 days with a suprachoroidal electrode array and six were chronically stimulated for 70-105 days at levels that ac...
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| Veröffentlicht in: | PloS one 2014-05, Vol.9 (5), p.e97182-e97182 |
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| creator | Nayagam, David A X Williams, Richard A Allen, Penelope J Shivdasani, Mohit N Luu, Chi D Salinas-LaRosa, Cesar M Finch, Sue Ayton, Lauren N Saunders, Alexia L McPhedran, Michelle McGowan, Ceara Villalobos, Joel Fallon, James B Wise, Andrew K Yeoh, Jonathan Xu, Jin Feng, Helen Millard, Rodney McWade, Melanie Thien, Patrick C Williams, Chris E Shepherd, Robert K |
| description | To assess the safety and efficacy of chronic electrical stimulation of the retina with a suprachoroidal visual prosthesis.
Seven normally-sighted feline subjects were implanted for 96-143 days with a suprachoroidal electrode array and six were chronically stimulated for 70-105 days at levels that activated the visual cortex. Charge balanced, biphasic, current pulses were delivered to platinum electrodes in a monopolar stimulation mode. Retinal integrity/function and the mechanical stability of the implant were assessed monthly using electroretinography (ERG), optical coherence tomography (OCT) and fundus photography. Electrode impedances were measured weekly and electrically-evoked visual cortex potentials (eEVCPs) were measured monthly to verify that chronic stimuli were suprathreshold. At the end of the chronic stimulation period, thresholds were confirmed with multi-unit recordings from the visual cortex. Randomized, blinded histological assessments were performed by two pathologists to compare the stimulated and non-stimulated retina and adjacent tissue.
All subjects tolerated the surgical and stimulation procedure with no evidence of discomfort or unexpected adverse outcomes. After an initial post-operative settling period, electrode arrays were mechanically stable. Mean electrode impedances were stable between 11-15 kΩ during the implantation period. Visually-evoked ERGs & OCT were normal, and mean eEVCP thresholds did not substantially differ over time. In 81 of 84 electrode-adjacent tissue samples examined, there were no discernible histopathological differences between stimulated and unstimulated tissue. In the remaining three tissue samples there were minor focal fibroblastic and acute inflammatory responses.
Chronic suprathreshold electrical stimulation of the retina using a suprachoroidal electrode array evoked a minimal tissue response and no adverse clinical or histological findings. Moreover, thresholds and electrode impedance remained stable for stimulation durations of up to 15 weeks. This study has demonstrated the safety and efficacy of suprachoroidal stimulation with charge balanced stimulus currents. |
| doi_str_mv | 10.1371/journal.pone.0097182 |
| format | Article |
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Seven normally-sighted feline subjects were implanted for 96-143 days with a suprachoroidal electrode array and six were chronically stimulated for 70-105 days at levels that activated the visual cortex. Charge balanced, biphasic, current pulses were delivered to platinum electrodes in a monopolar stimulation mode. Retinal integrity/function and the mechanical stability of the implant were assessed monthly using electroretinography (ERG), optical coherence tomography (OCT) and fundus photography. Electrode impedances were measured weekly and electrically-evoked visual cortex potentials (eEVCPs) were measured monthly to verify that chronic stimuli were suprathreshold. At the end of the chronic stimulation period, thresholds were confirmed with multi-unit recordings from the visual cortex. Randomized, blinded histological assessments were performed by two pathologists to compare the stimulated and non-stimulated retina and adjacent tissue.
All subjects tolerated the surgical and stimulation procedure with no evidence of discomfort or unexpected adverse outcomes. After an initial post-operative settling period, electrode arrays were mechanically stable. Mean electrode impedances were stable between 11-15 kΩ during the implantation period. Visually-evoked ERGs & OCT were normal, and mean eEVCP thresholds did not substantially differ over time. In 81 of 84 electrode-adjacent tissue samples examined, there were no discernible histopathological differences between stimulated and unstimulated tissue. In the remaining three tissue samples there were minor focal fibroblastic and acute inflammatory responses.
Chronic suprathreshold electrical stimulation of the retina using a suprachoroidal electrode array evoked a minimal tissue response and no adverse clinical or histological findings. Moreover, thresholds and electrode impedance remained stable for stimulation durations of up to 15 weeks. This study has demonstrated the safety and efficacy of suprachoroidal stimulation with charge balanced stimulus currents.</description><identifier>ISSN: 1932-6203</identifier><identifier>EISSN: 1932-6203</identifier><identifier>DOI: 10.1371/journal.pone.0097182</identifier><identifier>PMID: 24853376</identifier><language>eng</language><publisher>United States: Public Library of Science</publisher><subject>Animals ; Artificial vision ; Biocompatibility ; Biology and Life Sciences ; Cats ; Current pulses ; Effectiveness ; Electric Impedance ; Electric Stimulation ; Electrical stimuli ; Electrodes ; Electrodes, Implanted ; Electroretinograms ; Electroretinography ; Engineering and Technology ; Immunohistochemistry ; Implantation ; Inflammation ; Linear Models ; Mechanical properties ; Medical equipment ; Medicine and Health Sciences ; Neural prostheses ; Optical Coherence Tomography ; Otolaryngology ; Pathology ; Photography ; Photoreceptors ; Platinum ; Prostheses ; Prostheses and implants ; Research and Analysis Methods ; Retina ; Retina - pathology ; Retina - physiology ; Safety ; Stability analysis ; Stimulation ; Studies ; Surgery ; Thresholds ; Tomography, Optical Coherence ; Visual cortex ; Visual Cortex - physiology ; Visual Prosthesis - standards ; Visual stimuli</subject><ispartof>PloS one, 2014-05, Vol.9 (5), p.e97182-e97182</ispartof><rights>COPYRIGHT 2014 Public Library of Science</rights><rights>2014 Nayagam et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License: http://creativecommons.org/licenses/by/4.0/ (the “License”), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.</rights><rights>2014 Nayagam et al 2014 Nayagam et al</rights><lds50>peer_reviewed</lds50><oa>free_for_read</oa><woscitedreferencessubscribed>false</woscitedreferencessubscribed><citedby>FETCH-LOGICAL-c692t-c29db6ae7f94de0dddefe7a4bb9dc0761f254d25e35ef46e4a67cbb9086a254d3</citedby><cites>FETCH-LOGICAL-c692t-c29db6ae7f94de0dddefe7a4bb9dc0761f254d25e35ef46e4a67cbb9086a254d3</cites></display><links><openurl>$$Topenurl_article</openurl><openurlfulltext>$$Topenurlfull_article</openurlfulltext><thumbnail>$$Tsyndetics_thumb_exl</thumbnail><linktopdf>$$Uhttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC4031073/pdf/$$EPDF$$P50$$Gpubmedcentral$$Hfree_for_read</linktopdf><linktohtml>$$Uhttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC4031073/$$EHTML$$P50$$Gpubmedcentral$$Hfree_for_read</linktohtml><link.rule.ids>230,314,723,776,780,860,881,2096,2915,23845,27901,27902,53766,53768,79343,79344</link.rule.ids><backlink>$$Uhttps://www.ncbi.nlm.nih.gov/pubmed/24853376$$D View this record in MEDLINE/PubMed$$Hfree_for_read</backlink></links><search><contributor>Price, Nicholas Seow Chiang</contributor><creatorcontrib>Nayagam, David A X</creatorcontrib><creatorcontrib>Williams, Richard A</creatorcontrib><creatorcontrib>Allen, Penelope J</creatorcontrib><creatorcontrib>Shivdasani, Mohit N</creatorcontrib><creatorcontrib>Luu, Chi D</creatorcontrib><creatorcontrib>Salinas-LaRosa, Cesar M</creatorcontrib><creatorcontrib>Finch, Sue</creatorcontrib><creatorcontrib>Ayton, Lauren N</creatorcontrib><creatorcontrib>Saunders, Alexia L</creatorcontrib><creatorcontrib>McPhedran, Michelle</creatorcontrib><creatorcontrib>McGowan, Ceara</creatorcontrib><creatorcontrib>Villalobos, Joel</creatorcontrib><creatorcontrib>Fallon, James B</creatorcontrib><creatorcontrib>Wise, Andrew K</creatorcontrib><creatorcontrib>Yeoh, Jonathan</creatorcontrib><creatorcontrib>Xu, Jin</creatorcontrib><creatorcontrib>Feng, Helen</creatorcontrib><creatorcontrib>Millard, Rodney</creatorcontrib><creatorcontrib>McWade, Melanie</creatorcontrib><creatorcontrib>Thien, Patrick C</creatorcontrib><creatorcontrib>Williams, Chris E</creatorcontrib><creatorcontrib>Shepherd, Robert K</creatorcontrib><title>Chronic electrical stimulation with a suprachoroidal retinal prosthesis: a preclinical safety and efficacy study</title><title>PloS one</title><addtitle>PLoS One</addtitle><description>To assess the safety and efficacy of chronic electrical stimulation of the retina with a suprachoroidal visual prosthesis.
Seven normally-sighted feline subjects were implanted for 96-143 days with a suprachoroidal electrode array and six were chronically stimulated for 70-105 days at levels that activated the visual cortex. Charge balanced, biphasic, current pulses were delivered to platinum electrodes in a monopolar stimulation mode. Retinal integrity/function and the mechanical stability of the implant were assessed monthly using electroretinography (ERG), optical coherence tomography (OCT) and fundus photography. Electrode impedances were measured weekly and electrically-evoked visual cortex potentials (eEVCPs) were measured monthly to verify that chronic stimuli were suprathreshold. At the end of the chronic stimulation period, thresholds were confirmed with multi-unit recordings from the visual cortex. Randomized, blinded histological assessments were performed by two pathologists to compare the stimulated and non-stimulated retina and adjacent tissue.
All subjects tolerated the surgical and stimulation procedure with no evidence of discomfort or unexpected adverse outcomes. After an initial post-operative settling period, electrode arrays were mechanically stable. Mean electrode impedances were stable between 11-15 kΩ during the implantation period. Visually-evoked ERGs & OCT were normal, and mean eEVCP thresholds did not substantially differ over time. In 81 of 84 electrode-adjacent tissue samples examined, there were no discernible histopathological differences between stimulated and unstimulated tissue. In the remaining three tissue samples there were minor focal fibroblastic and acute inflammatory responses.
Chronic suprathreshold electrical stimulation of the retina using a suprachoroidal electrode array evoked a minimal tissue response and no adverse clinical or histological findings. Moreover, thresholds and electrode impedance remained stable for stimulation durations of up to 15 weeks. This study has demonstrated the safety and efficacy of suprachoroidal stimulation with charge balanced stimulus currents.</description><subject>Animals</subject><subject>Artificial vision</subject><subject>Biocompatibility</subject><subject>Biology and Life Sciences</subject><subject>Cats</subject><subject>Current pulses</subject><subject>Effectiveness</subject><subject>Electric Impedance</subject><subject>Electric Stimulation</subject><subject>Electrical stimuli</subject><subject>Electrodes</subject><subject>Electrodes, Implanted</subject><subject>Electroretinograms</subject><subject>Electroretinography</subject><subject>Engineering and Technology</subject><subject>Immunohistochemistry</subject><subject>Implantation</subject><subject>Inflammation</subject><subject>Linear Models</subject><subject>Mechanical properties</subject><subject>Medical equipment</subject><subject>Medicine and Health Sciences</subject><subject>Neural prostheses</subject><subject>Optical Coherence Tomography</subject><subject>Otolaryngology</subject><subject>Pathology</subject><subject>Photography</subject><subject>Photoreceptors</subject><subject>Platinum</subject><subject>Prostheses</subject><subject>Prostheses and implants</subject><subject>Research and Analysis Methods</subject><subject>Retina</subject><subject>Retina - pathology</subject><subject>Retina - physiology</subject><subject>Safety</subject><subject>Stability analysis</subject><subject>Stimulation</subject><subject>Studies</subject><subject>Surgery</subject><subject>Thresholds</subject><subject>Tomography, Optical Coherence</subject><subject>Visual cortex</subject><subject>Visual Cortex - physiology</subject><subject>Visual Prosthesis - standards</subject><subject>Visual 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Participant titles)</collection><collection>DOAJ Directory of Open Access Journals</collection><jtitle>PloS one</jtitle></facets><delivery><delcategory>Remote Search Resource</delcategory><fulltext>fulltext</fulltext></delivery><addata><au>Nayagam, David A X</au><au>Williams, Richard A</au><au>Allen, Penelope J</au><au>Shivdasani, Mohit N</au><au>Luu, Chi D</au><au>Salinas-LaRosa, Cesar M</au><au>Finch, Sue</au><au>Ayton, Lauren N</au><au>Saunders, Alexia L</au><au>McPhedran, Michelle</au><au>McGowan, Ceara</au><au>Villalobos, Joel</au><au>Fallon, James B</au><au>Wise, Andrew K</au><au>Yeoh, Jonathan</au><au>Xu, Jin</au><au>Feng, Helen</au><au>Millard, Rodney</au><au>McWade, Melanie</au><au>Thien, Patrick C</au><au>Williams, Chris E</au><au>Shepherd, Robert K</au><au>Price, Nicholas Seow Chiang</au><format>journal</format><genre>article</genre><ristype>JOUR</ristype><atitle>Chronic electrical stimulation with a suprachoroidal retinal prosthesis: a preclinical safety and efficacy study</atitle><jtitle>PloS one</jtitle><addtitle>PLoS One</addtitle><date>2014-05-22</date><risdate>2014</risdate><volume>9</volume><issue>5</issue><spage>e97182</spage><epage>e97182</epage><pages>e97182-e97182</pages><issn>1932-6203</issn><eissn>1932-6203</eissn><abstract>To assess the safety and efficacy of chronic electrical stimulation of the retina with a suprachoroidal visual prosthesis.
Seven normally-sighted feline subjects were implanted for 96-143 days with a suprachoroidal electrode array and six were chronically stimulated for 70-105 days at levels that activated the visual cortex. Charge balanced, biphasic, current pulses were delivered to platinum electrodes in a monopolar stimulation mode. Retinal integrity/function and the mechanical stability of the implant were assessed monthly using electroretinography (ERG), optical coherence tomography (OCT) and fundus photography. Electrode impedances were measured weekly and electrically-evoked visual cortex potentials (eEVCPs) were measured monthly to verify that chronic stimuli were suprathreshold. At the end of the chronic stimulation period, thresholds were confirmed with multi-unit recordings from the visual cortex. Randomized, blinded histological assessments were performed by two pathologists to compare the stimulated and non-stimulated retina and adjacent tissue.
All subjects tolerated the surgical and stimulation procedure with no evidence of discomfort or unexpected adverse outcomes. After an initial post-operative settling period, electrode arrays were mechanically stable. Mean electrode impedances were stable between 11-15 kΩ during the implantation period. Visually-evoked ERGs & OCT were normal, and mean eEVCP thresholds did not substantially differ over time. In 81 of 84 electrode-adjacent tissue samples examined, there were no discernible histopathological differences between stimulated and unstimulated tissue. In the remaining three tissue samples there were minor focal fibroblastic and acute inflammatory responses.
Chronic suprathreshold electrical stimulation of the retina using a suprachoroidal electrode array evoked a minimal tissue response and no adverse clinical or histological findings. Moreover, thresholds and electrode impedance remained stable for stimulation durations of up to 15 weeks. This study has demonstrated the safety and efficacy of suprachoroidal stimulation with charge balanced stimulus currents.</abstract><cop>United States</cop><pub>Public Library of Science</pub><pmid>24853376</pmid><doi>10.1371/journal.pone.0097182</doi><oa>free_for_read</oa></addata></record> |
| fulltext | fulltext |
| identifier | ISSN: 1932-6203 |
| ispartof | PloS one, 2014-05, Vol.9 (5), p.e97182-e97182 |
| issn | 1932-6203 1932-6203 |
| language | eng |
| recordid | cdi_plos_journals_1527403439 |
| source | Public Library of Science (PLoS) Journals Open Access; MEDLINE; DOAJ Directory of Open Access Journals; Elektronische Zeitschriftenbibliothek - Frei zugängliche E-Journals; PubMed Central; Free Full-Text Journals in Chemistry |
| subjects | Animals Artificial vision Biocompatibility Biology and Life Sciences Cats Current pulses Effectiveness Electric Impedance Electric Stimulation Electrical stimuli Electrodes Electrodes, Implanted Electroretinograms Electroretinography Engineering and Technology Immunohistochemistry Implantation Inflammation Linear Models Mechanical properties Medical equipment Medicine and Health Sciences Neural prostheses Optical Coherence Tomography Otolaryngology Pathology Photography Photoreceptors Platinum Prostheses Prostheses and implants Research and Analysis Methods Retina Retina - pathology Retina - physiology Safety Stability analysis Stimulation Studies Surgery Thresholds Tomography, Optical Coherence Visual cortex Visual Cortex - physiology Visual Prosthesis - standards Visual stimuli |
| title | Chronic electrical stimulation with a suprachoroidal retinal prosthesis: a preclinical safety and efficacy study |
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