Artificial vision with wirelessly powered subretinal electronic implant alpha-IMS

Abstract

This study aims at substituting the essential functions of photoreceptors in patients who are blind owing to untreatable forms of hereditary retinal degenerations. A microelectronic neuroprosthetic device, powered via transdermal inductive transmission, carrying 1500 independent microphotodiode-amplifier-electrode elements on a 9 mm2 chip, was subretinally implanted in nine blind patients. Light perception (8/9), light localization (7/9), motion detection (5/9, angular speed up to 35 deg s−1), grating acuity measurement (6/9, up to 3.3 cycles per degree) and visual acuity measurement with Landolt C-rings (2/9) up to Snellen visual acuity of 20/546 (corresponding to decimal 0.037 or corresponding to 1.43 logMAR (minimum angle of resolution)) were restored via the subretinal implant. Additionally, the identification, localization and discrimination of objects improved significantly (n = 8; p < 0.05 for each subtest) in repeated tests over a nine-month period. Three subjects were able to read letters spontaneously and one subject was able to read letters after training in an alternative-force choice test. Five subjects reported implant-mediated visual perceptions in daily life within a field of 15° of visual angle. Control tests were performed each time with the implant's power source switched off. These data show that subretinal implants can restore visual functions that are useful for daily life.

Long-term restoration of visual function in end-stage retinal degeneration using subretinal human melanopsin gene therapy

“…Even in end-stage disease, the remaining retinal layers and central visual projections remain structurally intact. Stimulation of these remaining cells is potentially sufficient to mimic visual responses and restore vision, and by this means the subretinal electronic implant has shown proof of principle for restoration of vision in patients after severe photoreceptor loss (2).…”

A CMOS 256-pixel Photovoltaics-powered Implantable Chip with Active Pixel Sensors and Iridium-oxide Electrodes for Subretinal Prostheses

“…(13,14) A wirelessly powered subretinal implant is designed with a subdermal coil embedded behind the ear. (15) In Refs. 9, 11, and 12, the optical powering scheme was proposed and the incident light was converted to stimulation currents by photodiodes.…”

“…(1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15) The stimulating electrodes of a subretinal implant are positioned under photoreceptors whereas those of an epiretinal implant are positioned above ganglion cells. In the subretinal implants, (8)(9)(10)(11)(12)(13)(14)(15) passive photodiode array, (9) active photodiode sensors with current amplifiers, (8,11,12) or active pixel circuits, (10,13) have been proposed. Most subretinal implants require a wire through the eyeball to provide power supply.…”

Study of Al-doped ZnO Transparent Stimulus Electrode for Fully Implantable Retinal Prosthesis with Three-dimensionally Stacked Retinal Prosthesis Chip

“…(8)(9)(10)(11)(12)(13) Figure 2 shows configurations of an epiretinal stimulation and a subretinal stimulation with the 3D stacked retinal prosthesis chip. The 3D stacked retinal prosthesis chip receives incident light and converts it into a biphasic stimulus current train, and the stimulus electrode array stimulates the remaining retinal cells.…”