Tests conducted on 21 patients suffering from retinitis pigmentosa - a disease that destroys light-receiving cells at the back of the eye - showed that 75 percent of them were able to correctly identify single letters and more than 50 percent were able to read four-letter words.
Lyndon da Cruz, consultant retinal surgeon at Moorfields Eye Hospital in London, told Sky News that the Argus II device can help restore some meaningful vision in patients, who otherwise would have been left blind.
He said that at the best they can start to read small 5cm letters formed into words.
The Argus II device, which is currently the only retinal prosthesis approved, has a camera that is mounted on a pair of glasses feeds images along a cable to an electronic chip that rests against the retina inside the eye, the chip stimulates the optic nerve, which carries signals to the visual processing centre of the brain, giving the wearer a highly-pixelated black and white view of the world.
The research has been published in the British Journal of Ophthalmology.