Hamburg: German scientists have invented a wireless bionic eyeball that can restore vision to patients who have become blind due to retina damage or disease.

The new prosthetic device caps 12 years of research to help these patients. This work has resulted in a unique system - a fully implantable visual prosthesis.

The scientists from the Fraunhofer Institute for Microelectronic Circuits and Systems in Duisburg, Germany, say that the bionic eye can bypass the damaged retina.

The system comprises an implant and an external transmitter integrated in an eyeglasses-frame.

The implant system converts the image patterns into interpretable stimulation signals, and data and energy are transferred to the implant by a telemetric link.

Nerve cells inside the eye are then stimulated according to the captured images.

The intact cells are innervated by means of 3-D stimulation electrodes that rest against the retina like small studs.

As long as there is no damage to the optic nerve, the vision signals can be sent to the brain just like they are with healthy eyes.

"For normally sighted people that may not seem much, but for the blind, it is a major step," comments Hoc Khiem Trieu of the Fraunhofer Institute.

"After years of blindness, the patients were able to see spots of light or geometric patterns, depending on how the nerve cells were stimulated."

Trieu has been involved from the outset of this project, which was funded by the Germany's education and research ministry.

Together with two other scientists, Ingo Krisch and DMichael Goertz, he translated the specifications given by the medical experts and material scientists into an implant and chip design.

"A milestone was reached when the prosthetic system finally operated wirelessly and remotely controlled," explains Dr. Krisch.

"A great deal of detailed work was necessary before the implant could be activated without any external cable connections."

"The designs became smaller and smaller, the materials more flexible, more robust and higher in performance, so that the implant now fits comfortably in the eye," reports Goertz.

The scientists are to receive the Joseph von Fraunhofer Prize 2008 for their work.