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Characteristics of prosthetic vision in rats with subretinal flat and pillar electrode arrays
OBJECTIVE: Retinal prostheses aim to restore sight by electrically stimulating the surviving retinal neurons. In clinical trials of the current retinal implants, prosthetic visual acuity does not exceed 20/550. However, to provide meaningful restoration of central vision in patients blinded by age-r...
Autores principales: | , , , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
2019
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7192047/ https://www.ncbi.nlm.nih.gov/pubmed/31341094 http://dx.doi.org/10.1088/1741-2552/ab34b3 |
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author | Ho, Elton Lei, Xin Flores, Thomas Lorach, Henri Huang, Tiffany Galambos, Ludwig Kamins, Theodore Harris, James Mathieson, Keith Palanker, Daniel |
author_facet | Ho, Elton Lei, Xin Flores, Thomas Lorach, Henri Huang, Tiffany Galambos, Ludwig Kamins, Theodore Harris, James Mathieson, Keith Palanker, Daniel |
author_sort | Ho, Elton |
collection | PubMed |
description | OBJECTIVE: Retinal prostheses aim to restore sight by electrically stimulating the surviving retinal neurons. In clinical trials of the current retinal implants, prosthetic visual acuity does not exceed 20/550. However, to provide meaningful restoration of central vision in patients blinded by age-related macular degeneration (AMD), prosthetic acuity should be at least 20/200, necessitating a pixel pitch of about 50 μm or lower. With such small pixels, stimulation thresholds are high due to limited penetration of electric field into tissue. Here, we address this challenge with our latest photovoltaic arrays and evaluate their performance in vivo. APPROACH: We fabricated photovoltaic arrays with 55 and 40 μm pixels (a) in flat geometry, and (b) with active electrodes on 10 μm tall pillars. The arrays were implanted subretinally into rats with degenerate retina. Stimulation thresholds and grating acuity were evaluated using measurements of the visually evoked potentials (VEP). MAIN RESULTS: With 55 μm pixels, we measured grating acuity of 48 ± 11 μm, which matches the linear pixel pitch of the hexagonal array. This geometrically corresponds to a visual acuity of 20/192 in a human eye, matching the threshold of legal blindness in the US (20/200). With pillar electrodes, the irradiance threshold was nearly halved, and duration threshold reduced by more than three-fold, compared to flat pixels. With 40 μm pixels, VEP was too low for reliable measurements of the grating acuity, even with pillar electrodes. SIGNIFICANCE: While being helpful for treating a complete loss of sight, current prosthetic technologies are insufficient for addressing the leading cause of untreatable visual impairment—AMD. Subretinal photovoltaic arrays may provide sufficient visual acuity for restoration of central vision in patients blinded by AMD. |
format | Online Article Text |
id | pubmed-7192047 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2019 |
record_format | MEDLINE/PubMed |
spelling | pubmed-71920472020-04-30 Characteristics of prosthetic vision in rats with subretinal flat and pillar electrode arrays Ho, Elton Lei, Xin Flores, Thomas Lorach, Henri Huang, Tiffany Galambos, Ludwig Kamins, Theodore Harris, James Mathieson, Keith Palanker, Daniel J Neural Eng Article OBJECTIVE: Retinal prostheses aim to restore sight by electrically stimulating the surviving retinal neurons. In clinical trials of the current retinal implants, prosthetic visual acuity does not exceed 20/550. However, to provide meaningful restoration of central vision in patients blinded by age-related macular degeneration (AMD), prosthetic acuity should be at least 20/200, necessitating a pixel pitch of about 50 μm or lower. With such small pixels, stimulation thresholds are high due to limited penetration of electric field into tissue. Here, we address this challenge with our latest photovoltaic arrays and evaluate their performance in vivo. APPROACH: We fabricated photovoltaic arrays with 55 and 40 μm pixels (a) in flat geometry, and (b) with active electrodes on 10 μm tall pillars. The arrays were implanted subretinally into rats with degenerate retina. Stimulation thresholds and grating acuity were evaluated using measurements of the visually evoked potentials (VEP). MAIN RESULTS: With 55 μm pixels, we measured grating acuity of 48 ± 11 μm, which matches the linear pixel pitch of the hexagonal array. This geometrically corresponds to a visual acuity of 20/192 in a human eye, matching the threshold of legal blindness in the US (20/200). With pillar electrodes, the irradiance threshold was nearly halved, and duration threshold reduced by more than three-fold, compared to flat pixels. With 40 μm pixels, VEP was too low for reliable measurements of the grating acuity, even with pillar electrodes. SIGNIFICANCE: While being helpful for treating a complete loss of sight, current prosthetic technologies are insufficient for addressing the leading cause of untreatable visual impairment—AMD. Subretinal photovoltaic arrays may provide sufficient visual acuity for restoration of central vision in patients blinded by AMD. 2019-10-30 /pmc/articles/PMC7192047/ /pubmed/31341094 http://dx.doi.org/10.1088/1741-2552/ab34b3 Text en Original content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence (http://creativecommons.org/licenses/by/3.0) . |
spellingShingle | Article Ho, Elton Lei, Xin Flores, Thomas Lorach, Henri Huang, Tiffany Galambos, Ludwig Kamins, Theodore Harris, James Mathieson, Keith Palanker, Daniel Characteristics of prosthetic vision in rats with subretinal flat and pillar electrode arrays |
title | Characteristics of prosthetic vision in rats with subretinal flat and pillar electrode arrays |
title_full | Characteristics of prosthetic vision in rats with subretinal flat and pillar electrode arrays |
title_fullStr | Characteristics of prosthetic vision in rats with subretinal flat and pillar electrode arrays |
title_full_unstemmed | Characteristics of prosthetic vision in rats with subretinal flat and pillar electrode arrays |
title_short | Characteristics of prosthetic vision in rats with subretinal flat and pillar electrode arrays |
title_sort | characteristics of prosthetic vision in rats with subretinal flat and pillar electrode arrays |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7192047/ https://www.ncbi.nlm.nih.gov/pubmed/31341094 http://dx.doi.org/10.1088/1741-2552/ab34b3 |
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