Safety Studies for a 44-Channel Suprachoroidal Retinal Prosthesis: A Chronic Passive Study

Abbott, Carla J; Nayagam, David A. X.; Luu, Chi D; Epp, Stephanie B.; Williams, Richard A.; Salinas-LaRosa, Cesar; Villalobos, Joel; McGowan, Ceara; Shivdasani, Mohit N.; Burns, Owen; Leavens, Jason; Yeoh, Jonathan; Brandli, Alice; Thien, Patrick C.; Zhou, Jiang; Feng, Helen; Williams, Chris; Shepherd, Robert K.; Allen, Penelope J

doi:10.1167/iovs.17-23086

Cited by 32 publications

(42 citation statements)

References 40 publications

(77 reference statements)

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“…Object identification and recognition require devices able to provide enough resolution. Wide-field arrays were so far designed for epiretinal placement only since large subretinal implants might encounter considerable difficulty in the surgical placement and represent a high risk of retinal detachment [31][32][33] . However, clinical trials showed that the best visual resolution was achieved using subretinal prostheses.…”

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confidence: 99%

Photovoltaic retinal prosthesis restores high-resolution responses to single-pixel stimulation in blind retinas

2021

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Retinal prostheses hold the promise of restoring vision in totally blind people. However, a decade of clinical trials highlighted quantitative limitations hampering the possibility of reaching this goal. A key challenge in retinal stimulation is to independently activate retinal neurons over a large portion of the subject’s visual field. Reaching such a goal would significantly improve the perception accuracy in retinal implants’ users, along with their spatial cognition, attention, ambient mapping and interaction with the environment. Here we show a wide-field, high-density and high-resolution photovoltaic epiretinal prosthesis for artificial vision (POLYRETINA). The prosthesis embeds 10,498 physically and functionally independent photovoltaic pixels, allowing for wide retinal coverage and high-resolution stimulation. Single-pixel illumination reproducibly induced network-mediated responses from retinal ganglion cells at safe irradiance levels. Furthermore, POLYRETINA allowed response discrimination with a high spatial resolution equivalent to the pixel pitch (120 µm) thanks to the network-mediated stimulation mechanism. This approach could allow mid-peripheral artificial vision in patients with retinitis pigmentosa.

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confidence: 99%

Photovoltaic retinal prosthesis restores high-resolution responses to single-pixel stimulation in blind retinas

2021

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“…The primary limitations of suprachoroidal stimulation relate to the proximity of the device to the retinal neurons. The BVA group is developing a next-generation 44-channel fully implantable device, 78 while also designing a 99-channel device, the Phoenix-99, which will incorporate a dual monopolar and hexapolar (‘quasi-monopolar’) stimulation pattern, to try and address the issues of retinotopic discrimination and high stimulation thresholds. 73,79…”

Section: Suprachoroidal Prosthesesmentioning

confidence: 99%

Advances in retinal prosthesis systems

2019

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Retinal prosthesis systems have undergone significant advances in the past quarter century, resulting in the development of several different novel surgical and engineering approaches. Encouraging results have demonstrated partial visual restoration, with improvement in both coarse objective function and performance of everyday tasks. To date, four systems have received marketing approval for use in Europe or the United States, with numerous others undergoing preclinical and clinical evaluation, reflecting the established safety profile of these devices for chronic implantation. This progress represents the first notion that the field of visual restorative medicine could offer blind patients a hope of real and measurable benefit. However, there are numerous complex engineering and biophysical obstacles still to be overcome, to reconcile the gap that remains between artificial and natural vision. Current developments in the form of enhanced image processing algorithms and data transfer approaches, combined with emerging nanofabrication and conductive polymerization techniques, herald an exciting and innovative future for retinal prosthetics. This review provides an update of retinal prosthetic systems currently undergoing development and clinical trials while also addressing future challenges in the field, such as the assessment of functional outcomes in ultra-low vision and strategies for tackling existing hardware and software constraints.

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“…There are over 1.5 million RGCs in the human retina (Harman et al, 2000) with the largest soma having a diameter of about 30 µm (Liu et al, 2017). Argus II devices stimulate with 60 electrodes, each of 200 µm in diameter (Dorn et al, 2013), Alpha AMS with 1600 electrodes, each of 30 µm (Stingl et al, 2017) and the BVA suprachoroidal devices with only 44 electrodes, each of 500 µm diameter (Ayton et al, 2014;Abbott et al, 2018). All of them are similar or far larger than the size of individual somas.…”

Section: Limited Spatial Resolutionmentioning

confidence: 99%

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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Safety Studies for a 44-Channel Suprachoroidal Retinal Prosthesis: A Chronic Passive Study

Abstract: The 44-channel suprachoroidal electrode array has an acceptable passive safety profile to proceed to clinical trial. The safety profile is expected to improve in human studies, as the complications seen are specific to limitations (anatomic differences) with the feline model.

Cited by 32 publications

References 40 publications

Photovoltaic retinal prosthesis restores high-resolution responses to single-pixel stimulation in blind retinas

Photovoltaic retinal prosthesis restores high-resolution responses to single-pixel stimulation in blind retinas

Advances in retinal prosthesis systems

Stimulation Strategies for Improving the Resolution of Retinal Prostheses

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