Scientists from the Bionic Eye Foundation at Sydney's Prince of Wales Hospital have launched human clinical trials of the device, which employs the same technology now routinely used in cochlear implants to restore hearing.

Professor Minas Coroneo said the trials involved placing small electrodes on the surface of the eye then using an electric current to stimulate the retina, the thin layer of cells in the back of the eye that respond to light.

Coroneo said a video camera attached to a pair of glasses was used to pick up images and transfer them to the electrodes via a computer.

The electrodes then stimulate the retina to send messages down the optic nerve to the visual area of the brain.

While it does not offer full sight, Coroneo said it could one day provide blind people with enough "functional vision" to negotiate their way across a room without bumping into objects.

"The patient will see a pattern of flashes that will outline objects," he told AFP.

"The aim is getting seeing-eye dogs back to being just pets."