Three-Dimensional Model of Electroretinogram Field Potentials in the Rat Eye

Selner, Ashley N.; Derafshi, Zahra; Kunzer, Brian; Hetling, John R.

doi:10.1109/tbme.2018.2816591

Cited by 9 publications

(12 citation statements)

References 33 publications

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“…To validate such prediction of the model, we calculated the electrical signal generated by the implant at the cornea for various alternating frequencies, ranging from 1 to 125 Hz. For this purpose, we created a computational model of the rat eye 21 and a head, with a photovoltaic array in the subretinal space (Fig. 5a ), as described in detail in Methods and in Supplementary Materials.…”

Section: Resultsmentioning

confidence: 99%

Electronic photoreceptors enable prosthetic visual acuity matching the natural resolution in rats

et al. 2022

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Localized stimulation of the inner retinal neurons for high-acuity prosthetic vision requires small pixels and minimal crosstalk from the neighboring electrodes. Local return electrodes within each pixel limit the crosstalk, but they over-constrain the electric field, thus precluding the efficient stimulation with subretinal pixels smaller than 55 μm. Here we demonstrate a high-resolution prosthetic vision based on a novel design of a photovoltaic array, where field confinement is achieved dynamically, leveraging the adjustable conductivity of the diodes under forward bias to turn the designated pixels into transient returns. We validated the computational modeling of the field confinement in such an optically-controlled circuit by in-vitro and in-vivo measurements. Most importantly, using this strategy, we demonstrated that the grating acuity with 40 μm pixels matches the pixel pitch, while with 20 μm pixels, it reaches the 28 μm limit of the natural visual resolution in rats. This method enables customized field shaping based on individual retinal thickness and distance from the implant, paving the way to higher acuity of prosthetic vision in atrophic macular degeneration.

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Section: Resultsmentioning

confidence: 99%

Electronic photoreceptors enable prosthetic visual acuity matching the natural resolution in rats

et al. 2022

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“…To further validate the spatiotemporal model in an implanted rat eye, we calculated the electrical signal generated by the implant at the cornea for various pulse repetition rates, ranging from 1 to 125 Hz with full-field illumination and with alternating gratings. For this purpose, we created a computational model of the rat’s eye 13 and a head, with the photovoltaic array implanted in the subretinal space (Figure 5A), as described in detail in Methods and the Supplementary Materials. The modeling results were compared with the in-vivo measurements of the corneal potential relative to a reference electrode in the nose.…”

Section: Resultsmentioning

confidence: 99%

“…To model the electric potential generated by a subretinal implant on the cornea, we constructed an anatomically realistic model of the rat eye, as described by Selner et al 13 , with adaptation for the thickness of a degenerate retina and a photovoltaic implant in the subretinal space. The corresponding COMSOL model file is accessible online 23 .…”

Section: Methodsmentioning

confidence: 99%

Electronic “photoreceptors” enable prosthetic vision with acuity matching the natural resolution in rats

Wang

Chen

Bhuckory

et al. 2021

Preprint

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Localized stimulation of the inner retinal neurons for high-acuity prosthetic vision requires small pixels and minimal cross-talk from neighboring electrodes. Local return electrodes within each pixel can limit the crosstalk, but they over-constrain the electric field, thus precluding the efficient stimulation with subretinal pixels smaller than 50 μm. Here we demonstrate a high-resolution prosthetic vision based on a novel design of a photovoltaic array, where field confinement is achieved dynamically, leveraging the adjustable conductivity of the diodes under forward bias to turn the designated pixels into transient returns. We validated computational modeling of the field confinement in such an optically-controlled circuit by ex-vivo and in-vivo measurements. Most importantly, we demonstrated that by using this strategy, the grating acuity of prosthetic vision with 20 μm pixels matches the 28 μm limit of the natural visual acuity in rats. This method will enable customized field shaping for each patient based on individual retinal thickness and distance from the implant, paving the way to prosthetic vision with acuity as high as 20/80 in atrophic macular degeneration.

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“…More work needs to be devoted to fully exploit the advantages of graphene MEA for ERG recordings. Specifically, accurate simulations [ 31 ] and the use of novel MEA encapsulation materials [ 32 ] could eventually pave the way to locate retinal injuries using topographical information of the corneal potential provided by MEAs.…”

Section: Discussionmentioning

confidence: 99%

“…For illustrative purposes, Figure S3 in the Supporting Information shows a particular example of an ERG measured with the linear MEA in which the electrodes in the nasal position record a significantly www.advmattechnol.de lower b-wave amplitude than the rest of the electrodes. However, the variability in the injury size and position, the natural variability of the ERG signal among different animals, the lack of a robust method to ensure the reproducible placement of the electrode from rat to rat and the small nature of the differences we were looking for (reported to be less than 3% [31] ) made impossible to confidently and systematically extract the position of the injury from the ERG signal differences measured with our MEA probes. Our results indicate that more work needs to be dedicated to understand how this new tool can be used to expand our understanding of the topography of ERGs in the cornea.…”

Section: Erg Recordings With Meamentioning

confidence: 99%

Single and Multisite Graphene‐Based Electroretinography Recording Electrodes: A Benchmarking Study

Cruz

Nguyen

Illa

et al. 2021

Adv Materials Technologies

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Electroretinography (ERG) is a clinical test employed to understand and diagnose many retinopathies. ERG is usually performed by placing a macroscopic ring gold wire electrode on the cornea while flashing light onto the eye to measure changes in the transretinal potential. However, macroscopic gold electrodes are severely limiting since they do not provide a flexible interface to contact the sensitive corneal tissue, making this technique highly uncomfortable for the patient. Another major drawback is the opacity of gold electrodes, which only allows them to record the ERG signal on the corneal periphery, preventing central ERG recordings. To overcome the limitations of metal‐based macroscopic ERG electrodes, flexible electrodes are fabricated using graphene as a transparent, flexible, and sensitive material. The transparency of the graphene is exploited to fabricate microelectrode arrays (MEAs) that are able to perform multisite recording on the cornea. The graphene‐based ERG electrodes are benchmarked against the widely used gold electrodes in a P23H rat model with photoreceptor degeneration. This study shows that the graphene‐based ERG electrodes can faithfully record ERGs under a wide range of conditions (light intensity, stage of photoreceptor degeneration, etc.) while offering additional benefits for ERG recordings such as transparency and flexibility.

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Three-Dimensional Model of Electroretinogram Field Potentials in the Rat Eye

Abstract: This model can now be used for optimization of ERG electrode design, and to support functional mapping of the retina from meERG data via solving the inverse bioelectric source problem.

Cited by 9 publications

References 33 publications

Electronic photoreceptors enable prosthetic visual acuity matching the natural resolution in rats

Electronic photoreceptors enable prosthetic visual acuity matching the natural resolution in rats

Electronic “photoreceptors” enable prosthetic vision with acuity matching the natural resolution in rats

Single and Multisite Graphene‐Based Electroretinography Recording Electrodes: A Benchmarking Study

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