FDTD investigation of a microwave link for data telemetry in retinal prosthesis applications

Retinitis pigmentosa (RP) or age-related macular degeneration (AMD) are leading causes of blindness worldwide. It has been shown that patients suffering from such diseases can recover partial vision by means of controlled electrical stimulation of the retina. Thus, a retinal prosthesis can be developed where the functionality of permanently damaged retinal photoreceptors is replaced by a 2D array of electrodes, which can provide electrical stimulation on the surface of the retina. A high bandwidth (of up to 30 MHz) microwave data telemetry link for a retinal prosthesis is computationally investigated. A pair of appropriately sized microstrip patch antennas (extra- and intraocular) has been designed. A high spatial resolution (0.25 mm) head-eye model has been developed and the coupling between the extraocular and intraocular units computed in free space and with the receiving antenna embedded in the model. A power coupling of -30 dB is obtained with the receiving antenna embedded in the model and -26 dB of coupling is obtained in free space. Modification of the current antenna designs to improve their gains is expected to lead to an enhancement in the coupling efficiency. Such high bandwidth data telemetry links can contribute to other potentially data intensive biomedical applications requiring chronically implanted electronic prosthetic devices.