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Implant Projects Visual Braille on Eye Retina of Blind

Author: Frontiers

Published: 2012-11-23 : (Rev. 2015-12-19)

Synopsis and Key Points:

Researchers stream braille patterns directly into a blind patients retina allowing him to read words accurately and quickly with an ocular neuro-prosthetic device.

Main Digest

Blind patient reads words stimulated directly onto the retina - Neuro-prosthetic device uses implant to project visual braille. For the very first time researchers have streamed braille patterns directly into a blind patient's retina, allowing him to read four-letter words accurately and quickly with an ocular neuro-prosthetic device.

Artificial devices that are grafted straight onto the brainstem, or into the brain itself. Neural prostheses are a series of devices that can substitute a motor, sensory or cognitive modality that might have been damaged as a result of an injury or a disease. Cochlear Implants are an example of such devices. Neuroprosthesis are currently in their infancy, but they offer two things that are truly wonderful: Bypassing the body, and letting the mind interface directly; Via AR, augmented body parts will be able to be fitted to the body, and controlled by the brain as if you were born with them - after a little training - without conscious thought.

The device, the Argus II, has been implanted in over 50 patients, many of who can now see color, movement and objects.

It uses a small camera mounted on a pair of glasses, a portable processor to translate the signal from the camera into electrical stimulation, and a microchip with electrodes implanted directly on the retina.

The study was authored by researchers at Second Sight, the company who developed the device, and has been published in Frontiers in Neuro-prosthetics on the 22nd of November.

This is the headset for the Argus II retinal implant device from Second Sight
This is the headset for the Argus II retinal implant device from Second Sight

"In this clinical test with a single blind patient, we bypassed the camera that is the usual input for the implant and directly stimulated the retina. Instead of feeling the braille on the tips of his fingers, the patient could see the patterns we projected and then read individual letters in less than a second with up to 89% accuracy," explains researcher Thomas Lauritzen, lead author of the paper.

Similar in concept to successful cochlear implants, the visual implant uses a grid of 60 electrodes, attached to the retina, to stimulate patterns directly onto the nerve cells.

For this study, the researchers at Second Sight used a computer to stimulate six of these points on the grid to project the braille letters.

A series of tests were conducted with single letters as well as words ranging in length from two letters up to four. The patient was shown each letter for half a second and had up to 80% accuracy for short words.

This shows the grid of electrons directly implanted on the retina
This shows the grid of electrons directly implanted on the retina

"There was no input except the electrode stimulation and the patient recognized the braille letters easily. This proves that the patient has good spatial resolution because he could easily distinguish between signals on different, individual electrodes." says Lauritzen.

According to Silvestro Micera at EPFL's Center for Neuro-prosthetics and scientific reviewer for the article, "this study is a proof of concept that points to the importance of clinical experiments involving new neuro-prosthetic devices to improve the technology and innovate adaptable solutions."

Primarily for sufferers of the genetic disease Retinitis Pigmentosa (RP), the implant Argus II has been shown to restore limited reading capability of large conventional letters and short words when used with the camera.

While reading should improve with future iterations of the Argus II, the current study shows how the Argus II could be adapted to provide an alternative and potentially faster method of text reading with the addition of letter recognition software.

This ability to perform image processing in software prior to sending the signal to the implant is a unique advantage of Argus II.

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