At Aachen University Clinic and the Fraunhofer Institute for Microelectronic Circuits in Germany, scientists are developing an epiretinal implant for people suffering from retinitis pigmentosa, reports EETimes. (Epiretinal means the prosthesis is placed on the surface of a patient’s damaged retina.) The device, capable of displaying images to the patient, was designed to receive both the video signal and the electricity necessary to power the implant wirelessly.
Presently, the device is equipped with 25 stimulating electrodes that are connected with ganglion cells. While the researchers admit that this is far from providing an actual eyesight experience, test persons said they were able to “see” electronically generated patterns or a coarse impression of the images they received.
The technology also helps eye specialist to simplify the implantation of such devices into the human eye. In comparison to wire-bound implants, the wireless device is much easier to implant into the eye and to wear, the university clinic said.
More details from the project page at RWTH Aachen University:
About 3 million people worldwide suffer from retinitis pigmentosa, making this one of the leading causes for blindness. In retinitis pigmentosa patients a slow and progressive degeneration of photoreceptors is observed, while about 30% of the retina’s ganglion cells remain intact. These ganglion cells are connected to the visual cortex of the brain via the optic nerve. Hence electrical stimulation of the remaining intact ganglion cells by placing micro electrodes onto the retina can in principal lead to visual sensation.
The idea is that the patient wears a pair of glasses which have an integrated CMOS camera. An image of the environment is taken and processed by a digital signal processor (the so-called retina encoder), which calculates a stimulation pattern for the electrodes placed onto the retina that reproduces the original image. Data and energy are then transferred via RF coupling to the implant inside the patient’s eye. Here a silicon chip generates bipolar current pulses that stimulate the intact ganglion cells of the retina via three-dimensional micro electrodes.
More from EETimes…
Those of you that are interested in the latest state of affairs in the world of retinal prostheses, should check out this excellent review at R&D Magazine, or look over Medgadget’s retinal prostheses archives.