Restoration of useful vision up to letter recognition capabilities using subretinal microphotodiodes

Abstract

Our group has developed a subretinal microphotodiode array for restoration of vision. In a clinical pilot study the array has been implanted in 11 patients suffering from photoreceptor degenerations. Here we present promising results from some of those patients where the retinal tissue above the chip was functional and the implant fulfilled its expected function. A spatial resolution of approximately 0.3 cycles/degree could be achieved with fine stripe patterns. In one subject where the implant had been placed directly under the macular region of the retina a visual acuity of 20/1000 could be measured. Artificially restored visual acuity of this quality has not been reported previously. Finally, we present images illustrating an approximation of how the visual perceptions might have appeared to the subjects, based on a mathematical model and patient reports.

Use of the Argus II Retinal Prosthesis to Improve Visual Guidance of Fine Hand Movements

“…1 Individuals suffering outer retinal blindness, such as late stage retinitis pigmentosa (RP) or dry age-related macular degeneration, may be able to recover some visual feedback with use of a retinal prosthesis. [2][3][4] These devices stimulate the remaining cells in the inner retina to convey signals to the visual cortex. In theory, stimulating remaining cells in a pattern corresponding to visual stimuli could create visual percepts resembling those stimuli.…”

Angiographic findings following tack fixation of a wireless epiretinal retina implant device in blind RP patients

“…In comparison to the epiretinal approach, the use of a subretinal prosthesis does not require any additional fixation tool, as the stimulator remains in stable position after insertion into the subretinal space [20,21]. However, the EPIRET3 approach allows a complete intraocular implantation with wireless energy and signal supply from outside, while the subretinal prostheses require a transchoroidal and transscleral cable connection to the energy source outside the eyeball, which may reveal a certain risk potential in this area.…”

Retinal prostheses in degenerative retinal diseases

“…25 While image acquisition is solely intraocular, a cable connecting the implant to a subdermal power control unit, which charges wirelessly through a handheld control unit, enables light-sensitivity adjustment. 26,27 Early models with a transdermal power supply limited the study to 126 days. However, wireless power supply has eliminated the time limitation in later trials.…”