|The eye implant works by replacing light sensors that are lost as a result of the disease [GALLO/GETTY]
Scientists in Germany have developed an eye implant that allowed three blind patients to see shapes and objects in a breakthrough that could revolutionise eyesight treatment.
Experts have said the device could eventually change the lives of up to 200,000 people who suffer a form of inherited blindness called retinitis pigmentosa.
The research, published on Wednesday in the Proceedings of the Royal Society B, a British biological research journal, was described as representing "an unprecedented advance in electronic visual prostheses".
Eberhart Zrenner, lead researcher of the study and director of Retinal Implant AG, the German company developing the device, said further trials would now be taken in around 25 to 50 patients across Europe.
"We have shown that people can be provided with enough useful vision for daily life," he was quoted as saying by the Reuters news agency.
Retinitis pigmentosa is a degenerative disease in which light receptors in the retina, on the back of the eyeball, gradually cease to function.
According to the study, one blind patient who was given the implant was able to identify and find objects placed on a table in front of him, and was able to walk around a room independently.
"Three previously blind persons could locate bright objects on a dark table, two of whom could discern grating patterns," the paper said.
"One of these patients was able to correctly describe and name objects like a fork or knife on a table, geometric patterns, different fruits and discern shades of grey with only 15 per cent contrast.
"Without a training period, the regained visual functions enabled him to localise and approch persons in a room freely and to read large letters as complete words after several years of blindness."
Robert Maclaren, a professor of ophthalmology at Britain's Oxford University said the findings were "very exciting".
"It proves the concept that in a patient who has been blind for many years and is unable to see anything, the optic nerves can be re-awakened for them to be able to see again," MacLaren, who was not involved in the study, told Reuters.
"To go from being completely blind for many years, to being able to read a few letters and see shapes is an amazing step."
The device, called a sub-retinal implant, contains some 1,500 light sensors and sits underneath the retina.
It works by directly replacing light receptors that are lost as a result of the disease.
After the light detection stage, it uses the eye's natural image-processing functions to produce a stable visual image.
It was developed by the Retinal Implant AG alongside the Institute for Ophthalmic Research at the University of Tuebingen in Germany.