An implant system includes an implant, which is configured to be implanted in a body of a subject, and an external controller. The external controller includes a wireless energy transmitter. The implant comprises a wireless energy receiver, which is configured to receive energy from the wireless energy transmitter and one or more electrical light sources, which are (a) electrically coupled to the wireless energy receiver, and (b) configured to emit light upon being triggered by the wireless energy receiver receiving the energy from the wireless energy transmitter.
