First Human Results With the 256 Channel Intelligent Micro Implant Eye (IMIE 256)

Abstract

Purpose To report on the safety and efficacy of the 256-channel Intelligent Micro Implant Eye epiretinal prosthesis system (IMIE 256). Methods The IMIE 256 implants were implanted in the right eyes of five subjects with end-stage retinitis pigmentosa. Following implantation, the subjects underwent visual rehabilitation training for 90 days, and their visual performance was evaluated using the grating visual acuity test, Tumbling E visual acuity test, direction of motion, square localization, and orientation and mobility test. To evaluate the safety of the IMIE 256, all adverse events were recorded. Results Subjects performed significantly better on all evaluations with the IMIE 256 system on as compared with the performance at baseline or with the system off. There was a steady improvement in performance at each observation interval, indicating that the training and/or practice helped the subjects use the IMIE 256. There were two serious adverse events—electrode array movement and low intraocular pressure in one subject, which resolved with surgery. There were no other adverse events observed except those expected in the course of postoperative healing. Conclusions These results show an improved safety and efficacy profile compared with that of the Argus II implant. Further clinical trials are needed to confirm these results in a larger number of subjects and over longer durations. Translational Relevance To our knowledge, this study reports the first in-human data from a high-density (256 electrodes) epiretinal implant to restore sight to a subset of blind patients.

Sequential epiretinal stimulation improves discrimination in simple shape discrimination tasks only

“…Different neural targets along the visual pathway can be stimulated to elicit flashes of light known as phosphenes, which can be used as rudimentary visual feedback for people with blindness. To date, visual neuroprostheses have been implanted for at least several months in the retina (Humayun et al 2012; Stingl et al 2013; Fujikado et al 2016; Petoe et al 2021; Barnes et al 2016; Palanker et al 2022; Xu et al 2021), optic nerve (Veraart et al 2003), and visual cortex of human subjects (Beauchamp et al 2020; Fernández et al 2021). The Argus® II (Second Sight Medical Products, Sylmar, CA, USA) is a device that was implanted commercially in the United States from 2014 through 2020.…”

A thin-film optogenetic visual prosthesis

“…The FlexLED device described in this study has 8,192 pixels at up to 90 FPS at 8-bit global intensity levels. In comparison, no previous retinal stimulation device of which we are aware has achieved this pixel density 20,22 (1250 px/mm 2 ). This version of the FlexLED uses a passive driver, which limits frame rates when taken in conjunction with the minimum times required to reliably elicit optogenetically-evoked action potentials at safe light levels.…”

“…As expected, high contrast full-field visual stimuli from a computer monitor failed to evoke significant responses (Figure 4f-g). In contrast, full-field excitation using a 530 nm LED light elicited responses across the ECoG grid (Figure 4b-e), with a median of 16 channels (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22) interquartile range) displaying significant responses (Figure 4b). This wide-spread activation of 8 3d), and likely reflects activation of opsin-expressing RGCs distributed widely in the retina.…”

“…Early retinal prostheses placed arrays of electrodes on the retinal surface to activate RGCs to create visual sensation 17, 18 . Electrode arrays such as the Argus II and IMIE 256 used a through-sclera via to couple retinal electrode arrays to extraocular electronics packages driven by a wearable device that provides wireless data and power 19, 20 . While these devices generate visual sensations, they suffer from poor resolution.…”

Evaluation of the Long-Term Clinical Results of 3 Patients Implanted with the Argus II Retinal Prosthesis

“…In a recent study, the IMIE 256 epiretinal prosthesis containing 256 electrodes was implanted in 5 Chinese patients, 4 with RP and 1 with Usher syndrome, and was explanted after 90 days as per protocol. 23 This implant is based on a working principle similar to that of the Argus II epiretinal prosthesis, with an electrode array 4.75x6.50 mm in size, and 4 of the patients achieved a visual acuity of 20/1200. Studies to improve the safety, feasibility, resolution, and functionality of epiretinal prostheses, especially in patients with end-stage hereditary retinal degeneration, are ongoing.…”