Miniature wireless retinal implant

A wireless miniature epiretinal stimulator implant is reported. The power and data delivery to the implant is achieved using near-infrared pulses of laser beam operated within the safe illumination intensities. The the implant's 256 electrodes are controlled using an application-specific integrated circuit (ASIC). The ASIC is powered using an advanced photovoltaic (PV) cell and programmed using a single photodiode. High density packaging methods are using to implement the implant circuitry, as well as individual connections between a stimulator chip and 256 electrically conductive nitrogen-doped ultrananocrystalline diamond electrodes with a high charge injection capacity needed for effective simulation of retinal ganglion cells. The device is encapsulated in an optically transparent, mechanically robust and bioinnert diamond capsule. A PV cell with a monochromatic power conversion efficiency of 55% and operated within the safety limits is used to provide 15 mW of power the implant. A photodiode is used to detect the pulse modulate forward data telemetry of stimulation parameters at bandwidth of 3.7 MHz. Laser power delivery enables a high degree of miniaturisation and lower surgical complexity, partially when compared to implants using coils for power and data transfer. This development provides a route to fully wireless miniaturized minimally invasive implants with sophisticated functionalities, in the eye or under the skin.