A team of doctors have said that they have used an eye implant to help blind patients regain useful sight only weeks after undergoing the treatment.

They said that the patients who have an inherited form of blindness called retinitis pigmentosa (RP) regained their vision weeks after a light-sensitive microchip was inserted into the back of their eye. The treatment replicates the natural method in which the eye processes light and sends messages to the brain.

The process allowed patents to distinguish between black and white and also allowed them to see the rough edges of an object. Doctors say that the patients' brains have to learn about how to see things after years of blindness and there are hopes that the vision will improve in the coming time as the pateitns continue to use the mechanism.

Researchers claim that the treatment could further be refined to improve the sight of people with less severe retinal conditions that affect hundreds of thousands of people. The implant, which is developed by Retina Implant AG, is placed under a patient's retina at the back of the eye uses the eyes natural focusing power to transmit light. It then uses 1,500 electrodes to convert light into electrical impulses that are passes on to optic nerve into the brain.

Dr Tim Jackson, a consultant retinal surgeon at King's College Hospital and one of the trial leaders, explained: "You can think of the retina as the film in the back of a camera. That has died away but the remaining connections are still intact and we can use these to transmit a signal to the brain."