By James Gallagher
Health and science reporter, BBC News
A retinal implant - or bionic eye - which is powered by light has been invented by scientists at Stanford University in California.
Implants currently used in patients need to be powered by a battery.
The new device, described in the journal Nature Photonics, uses a special pair of glasses to beam near infrared light into the eye.
This powers the implant and sends the information which could help a patient see.