Controlled drug delivery 3 Controllers 3 Cost effectiveness 3 Digital controller designs 3 Digital controllers 3 Field programmable gate arrays (FPGA) 3 Field programmables 3 Field-programmable gated array 3 Hexagonal stimulation 3 Implant devices 3 Implants (surgical) 3 Integrated circuit design 3 Micro/nano 3 Ophthalmology 3 Retinal implant technology 3 Subretinal implants 3 Wireless telemetry systems 3 digital controller 3 field-programmable gated arrays hexagonal stimulation 3 wireless telemetry system 3