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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...

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Autores principales: Ho, Elton, Lei, Xin, Flores, Thomas, Lorach, Henri, Huang, Tiffany, Galambos, Ludwig, Kamins, Theodore, Harris, James, Mathieson, Keith, Palanker, Daniel
Formato: Online Artículo Texto
Lenguaje:English
Publicado: 2019
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.
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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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