Human Volunteers Test Implantable Vision Chip

(Image courtesy IMI)

Clinical research to develop artificial vision devices has accelerated greatly over the past 3 years. American researchers first introduced a retinal chip with 16 electrodes called Second Sight back in 2003. German scientists have recently reported their success with an innovative 50-electrode retinal chip they call the Learning Retinal Implant (LRI).

The normal visual pathway consists of light rays that stimulate the retina which, in turn, transmits a neural signal to the brain. People with hereditary and degenerative eye disorders have a problem with the conversion of the light impulse into an electrical charge. They lack a healthy supply of vision cells called photoreceptors. This is where the retinal chip does its job.

So far, four blind human volunteers have received LRIs. Customized spectacles have a miniature camera mounted in the frame that transmits the camera image to a tiny computer carried in a fanny pack (the developers use a more sophisticated name). The computer sends a wireless digital signal to the chip. Electrodes inside the chip directly stimulate the retinal ganglion cells and a visual 'image' is sent to the brain.

Retinal chip recipients report the presence of lights and shapes. True, this new 'vision' is very crude compared to your ability to read this blog, however, for individuals denied all eyesight most of their lives the recovery of any visual stimulation is a remarkable achievement. The inventors behind both of these retinal chips forecast continued success as optoelectronic technology evolves.

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