Retinal Implant Helps Restore Vision

Diagram of visual prosthesis
The major components of the new prosthesis. The small wearable computer is not included. Credit: Mark Humayun/AAAS. Source: New Scientist.

An article by Gaia Vince in New Scientist reports on a retinal prosthesis designed to help restore vision to blind people. After a prototype was successfully used in six people, further trials are set to begin. While cochlear implants are used to give deaf people some ability to hear, there has been no comparable, practical system for those who cannot see.

The system has several components. The user wears a pair of glasses with a built-in camera. The information is then transmitted to a wireless computer around the size of a mobile telephone that the user must keep with him. This computer processes the data, then transmits it to a receiver implanted in the user’s head. This is connected to a chip on the user’s retina. This all occurs extremely quickly, as discrepancy between perceived movement and visual changes would cause nausea and dizziness.

The device is still preliminary; the resolution is quite limited, naturally. But it is interesting that the brains of the patients seem to adapt to the limited visual input, and their vision improved over time. The article notes one patient’s observation:

At the beginning, it was like seeing assembled dots — “now it’s much more than that,” says Terry Bryant, aged 58, who received the implant in 2002 after 13 years of blindness. “I can go into any room and see the light coming in through the window. When I am walking along the street I can avoid low hanging branches and I can cross a busy street.”

Similar to the cochlear implant, an intact nervous system is required. This prothesis links with the ganglion cells at the back of the eye and the signals travel over the optic nerve to the brain. Damage to any of these components—such as damage to the ganglion cells, injury to the optic nerve, or stroke—will result in blindness that this prosthesis cannot correct. For that, we’ll have to wait for new technology.

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4 thoughts on “Retinal Implant Helps Restore Vision

  1. Wow, not too shaby for just 60 electrodes on that implant. I wonder, with our body’s high adaptability, and as the impulses from the implant get transmitted along the optic nerve to the brain – if the user could eventually develop better image resolution – compensating for the definition in the brain – much like a person with damage in one part of the brain compensates by having another section more active. In any case, grandma was shootin’ basketball hoops while wearing this device – and it astounds me with what precision she was able to measure the distance. I mean, try aiming for the basket with one eye open 🙂

  2. The ability of the brain to adapt is remarkable. It is also quite good at hiding how limited its sensory information really is. I have no doubt that people with this sort of implant could eventually acquire better vision than one might expect from the design of the implant.

  3. Linking up to a healthy system and projecting data from a television into the prosthesis will give you TV on demand.

  4. Very true, Randall. I have no doubt that a successor to this system will one day allow humans to aumgent their sight—perhaps by expanding their sensory range, by supplying information (sort of a “heads-up display”), or more.

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