Australian researchers developing a "bionic eye" say early tests have succeeded in stimulating limited visual sensation in people suffering a rare form of genetic blindness.

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.

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."

The stimulation achieved so far is extremely limited, but researcher Vivek Chowdhury said it was enough to spark a tearful response from his first successful patient when she saw a single spot of light after years of darkness.

"It's a combination of excitement and surprise and shock, it's quite scary to be seeing these things that they haven't seen before," Chowdhury told ABC television.

Coroneo said the prototype bionic eye was a low-risk device for patients because it sat on the eye's surface and did not require invasive surgery.

He said it was an exciting development for people suffering conditions such as retinitis pigmentosa, an irreversible genetic condition where the retina's cells gradually die but the optic nerve survives.

The researchers are also developing a second type of bionic eye that involves electrodes implanted directly onto the brain's visual area, meaning it could help patients whose optic nerve has been destroyed.

Source: PhysOrg