We have always had a fascination with robotic eyes, whether in RoboCop or Terminator, and we have previously covered some of the exciting developments in retinal implants. MIT is reporting that its researchers, led by Dr. John L. Wyatt, are working on a retinal implant that bypasses damaged retinal cells in order to give direct visual input to the brain.
The implant works in conjunction with a specially designed set of glasses that have an embedded camera that wirelessly transmits power and image signals to the microchip in the retina which then transmits the signals to the brain. The microchip has receiving coils that surround the eyeball, much like a natural retina. The microchip itself is sealed in a titanium case to avoid corrosion. The chip will receive visual signals from the glasses which activate the electrodes, which in turn fire nerve cells to carry visual input to the brain. The microchip will not restore vision to a perfect standing, but is intended to help a blind patients navigate.
The following is taken from an MIT press office statement:
One question that remains is what kind of vision this direct electrical stimulation actually produces. About 10 years ago, the research team started to answer that by attaching electrodes to the retinas of six blind patients for several hours.
When the electrodes were activated, patients reported seeing a small number of “clouds” or “drops of blood” in their field of vision, and the number of clouds or blood drops they reported corresponded to the number of electrodes that were stimulated. When there was no stimulus, patients accurately reported seeing nothing. Those tests confirmed that retinal stimulation can produce some kind of organized vision in blind patients, though further testing is needed to determine how useful that vision can be.
After those initial tests, with grants from the Boston Veteran’s Administration Medical Center and the National Institutes of Health, the researchers started to build an implantable chip, which would allow them to do more long-term tests. Their goal is to produce a chip that can be implanted for at least 10 years.
One of the biggest challenges the researchers face is designing a surgical procedure and implant that won’t damage the eye. In their initial prototypes, the electrodes were attached directly atop the retina from inside the eye, which carries more risk of damaging the delicate retina. In the latest version, described in the October issue of IEEE Transactions on Biomedical Engineering, the implant is attached to the outside of the eye, and the electrodes are implanted behind the retina…
While they have not yet begun any long-term tests on humans, the researchers have tested the device in Yucatan miniature pigs, which have roughly the same size eyeballs as humans. Those tests are only meant to determine whether the implants remain functional and safe and are not designed to observe whether the pigs respond to stimuli to their optic nerves.
So far, the prototypes have been successfully implanted in pigs for up to 10 months, but further safety refinements need to be made before clinical trials in humans can begin.
Press release: Stimulating sight…
MIT Research Lab: Retinal Implant Research Group…
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