Honeycomb-shaped electro-neural interface enables cellular-scale pixels in subretinal prosthesis

Flores, Thomas; Huang, Tiffany; Bhuckory, Mohajeet; Ho, Elton; Chen, Zhijie Charles; Dalal, Roopa; Galambos, Ludwig; Kamins, Theodore I.; Mathieson, Keith; Palanker, Daniel

doi:10.1038/s41598-019-47082-y

Cited by 61 publications

(112 citation statements)

References 46 publications

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“…When converting the value into human visual acuity, the result is close to 20/192, which is just within the legal blindness threshold of 20/200. Following these studies, they also proposed honeycomb-shaped electrodes for sub-retinal stimulation (Flores et al, 2019), where the stimulating electrodes sit within a deep honeycomb well, the walls of the well acting as the local returns. Experimentally (Flores et al, 2019) they demonstrated that the inner retinal cells migrated into the 25 µm deep wells after 5 weeks of implantation.…”

Section: Spatial Resolutionmentioning

confidence: 99%

“…Following these studies, they also proposed honeycomb-shaped electrodes for sub-retinal stimulation (Flores et al, 2019), where the stimulating electrodes sit within a deep honeycomb well, the walls of the well acting as the local returns. Experimentally (Flores et al, 2019) they demonstrated that the inner retinal cells migrated into the 25 µm deep wells after 5 weeks of implantation. No experimental stimulating results have been published using such arrays, but from simulation, the visual acuity is expected to be better than 20/100.…”

Section: Spatial Resolutionmentioning

confidence: 99%

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Stimulation Strategies for Improving the Resolution of Retinal Prostheses

et al. 2020

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Electrical stimulation using implantable devices with arrays of stimulating electrodes is an emerging therapy for neurological diseases. The performance of these devices depends greatly on their ability to activate populations of neurons with high spatiotemporal resolution. To study electrical stimulation of populations of neurons, retina serves as a useful model because the neural network is arranged in a planar array that is easy to access. Moreover, retinal prostheses are under development to restore vision by replacing the function of damaged light sensitive photoreceptors, which makes retinal research directly relevant for curing blindness. Here we provide a progress review on stimulation strategies developed in recent years to improve the resolution of electrical stimulation in retinal prostheses. We focus on studies performed with explanted retinas, in which electrophysiological techniques are the most advanced. We summarize achievements in improving the spatial and temporal resolution of electrical stimulation of the retina and methods to selectively stimulate neurons with different visual functions. Future directions for retinal prostheses development are also discussed, which could provide insights for other types of neuromodulatory devices in which high-resolution electrical stimulation is required.

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Section: Spatial Resolutionmentioning

confidence: 99%

Section: Spatial Resolutionmentioning

confidence: 99%

Stimulation Strategies for Improving the Resolution of Retinal Prostheses

et al. 2020

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“…We believe that these results may improve further by introducing highly localized electrical stimuli atop and/or beside penetrating posts that support the electrode structures. Indeed, we have fabricated such high-density 3D penetrating electrode arrays for our own devices, as have other groups more recently [ 18 , 19 , 20 , 21 ], and we report on their fabrication technology below.…”

Section: Introductionmentioning

confidence: 98%

Micro-Fabrication of Components for a High-Density Sub-Retinal Visual Prosthesis

Shire¹,

Gingerich²,

Wong³

et al. 2020

Micromachines

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We present a retrospective of unique micro-fabrication problems and solutions that were encountered through over 10 years of retinal prosthesis product development, first for the Boston Retinal Implant Project initiated at the Massachusetts Institute of Technology and at Harvard Medical School’s teaching hospital, the Massachusetts Eye and Ear—and later at the startup company Bionic Eye Technologies, by some of the same personnel. These efforts culminated in the fabrication and assembly of 256+ channel visual prosthesis devices having flexible multi-electrode arrays that were successfully implanted sub-retinally in mini-pig animal models as part of our pre-clinical testing program. We report on the processing of the flexible multi-layered, planar and penetrating high-density electrode arrays, surgical tools for sub-retinal implantation, and other parts such as coil supports that facilitated the implantation of the peri-ocular device components. We begin with an overview of the implantable portion of our visual prosthesis system design, and describe in detail the micro-fabrication methods for creating the parts of our system that were assembled outside of our hermetically-sealed electronics package. We also note the unique surgical challenges that sub-retinal implantation of our micro-fabricated components presented, and how some of those issues were addressed through design, materials selection, and fabrication approaches.

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“…14 Novel electrode designs and advances in targeted stimulation strategies offer some promise for future visual prostheses. [15][16][17][18] Despite current technical limitations, users of present-day retinal implants have demonstrated improved performance in activities of daily living and in tasks involving navigation, obstacle avoidance, and light localisation (Kolic M. IOVS. 2020;61:ARVO Abstract 2199; Petoe MA.…”

Section: Introductionmentioning

confidence: 99%

Oculomotor Responses to Dynamic Stimuli in a 44-Channel Suprachoroidal Retinal Prosthesis

Titchener

Kvansakul

Shivdasani

et al. 2020

Trans. Vis. Sci. Tech.

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Purpose To investigate oculomotor behavior in response to dynamic stimuli in retinal implant recipients. Methods Three suprachoroidal retinal implant recipients performed a four-alternative forced-choice motion discrimination task over six sessions longitudinally. Stimuli were a single white bar (“moving bar”) or a series of white bars (“moving grating”) sweeping left, right, up, or down across a 42″ monitor. Performance was compared with normal video processing and scrambled video processing (randomized image-to-electrode mapping to disrupt spatiotemporal structure). Eye and head movement was monitored throughout the task. Results Two subjects had diminished performance with scrambling, suggesting retinotopic discrimination was used in the normal condition and made smooth pursuit eye movements congruent to the moving bar stimulus direction. These two subjects also made stimulus-related eye movements resembling optokinetic reflex (OKR) for moving grating stimuli, but the movement was incongruent with stimulus direction. The third subject was less adept at the task, appeared primarily reliant on head position cues (head movements were congruent to stimulus direction), and did not exhibit retinotopic discrimination and associated eye movements. Conclusions Our observation of smooth pursuit indicates residual functionality of cortical direction-selective circuits and implies a more naturalistic perception of motion than expected. A distorted OKR implies improper functionality of retinal direction-selective circuits, possibly due to retinal remodeling or the non-selective nature of the electrical stimulation. Translational Relevance Retinal implant users can make naturalistic eye movements in response to moving stimuli, highlighting the potential for eye tracker feedback to improve perceptual localization and image stabilization in camera-based visual prostheses.

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Honeycomb-shaped electro-neural interface enables cellular-scale pixels in subretinal prosthesis

Cited by 61 publications

References 46 publications

Stimulation Strategies for Improving the Resolution of Retinal Prostheses

Stimulation Strategies for Improving the Resolution of Retinal Prostheses

Micro-Fabrication of Components for a High-Density Sub-Retinal Visual Prosthesis

Oculomotor Responses to Dynamic Stimuli in a 44-Channel Suprachoroidal Retinal Prosthesis

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