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Artificial Retinas Bring Vision Back To The Blind
Patters writes "Researchers from the University of California and the Doheny Eye Institute have successfully implanted a tiny electronic eye implant with a video camera mounted on a pair of sunglasses into 6 patients, allowing them to detect light and motion. The implant is a 4-by-4 grid of electrodes which connects to damaged photoreceptors (rods and cones) on the patient's retina. It works by stimulating the photoreceptors, transmitting signals through the optic nerve to the brain. The implant only works on patients with degenerated rods and cones, and is named after Argus, the Greek god which had 100 eyes. If the implants continue to be a success, the artificial retinas could be available to the public within the next 3 years."
It's not the University of California, it's the University of Southern California. There's a big difference.
You are absolutely right. Many experiments have shown that if vision is impaired during certain critical developmental periods, then normal vision will never be possible, even if their eyes work perfectly. (The work began with Hubel and Wiesel's work on kittens, for which they received the 1981 Nobel Prize in medicine, but has been extended by many others.) These experiments have even shown that you can limit vision in certain ways (blocking out only one part of a visual field, for instance, or letting them mature in an environment devoid of a particular class of visual cue) and the animal will simply have that part of their visual system undeveloped (while other parts still work).
So there is no way that those born without vision will ever attain what we consider normal vision. That having been said, it may be possible that they can achieve some rudimentary visual capabilities. For instance, they may learn to use the stimulus from a 4X4 grid in order to help them know when objects are approaching, or to better interpret their other senses. It isn't much, but for someone who has been blind their whole life, even some vague visual information (like knowing how bright their surroundings are!) may be helpful. Obviously more research is necessary in order to know if even these limited abilities can be learned later in life.
*sigh* This story has been around for years. Here is a better resolution version from 2000: Artifical Retinas
OK, so like the other posters have said, there is considerable processing that occurs in the brain. However, most people are not aware of how much visual processing actually occurs in the retina. Hint: it is considerable.
As for the results that Humayan et al are showing to great effect, there are major problems aside from the engineering ones. First off, part of my PhD dissertation was on just this problem of retinal degeneration. It turns out that the implants they are designing are not taking into account some of the most basic issues of biology. Notably that any time you deafferent a CNS system, it remodels. They will have to deal with remodeling and continuously degenerating retina. In order for implants like this to work, we need to arrest retinal remodeling or take advantage of it to enable wiring into bionic or artificial biological circuits.
From an engineering standpoint, traditional electrode grids like this will end up with other problems. Notably, the issue of heating. You don't want to cook your retinas, so the need for very small currents with microelectrodes are what will be necessary. I show one such bionic implant on my blog here.
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Actually, the blind spots are an artifact of the physical construction of the human eye. It's where your nerves leave the eyeball.
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These inventions seems to appear often here
But rarely in real life...
"You might get it to work if you implanted them in an infant, but that would be kind of rough having to buy new eyes frequently during periods of rapid growth."
No, you'd never have to buy new ones: newborns arrive with eyeballs the same size as an adult. That's why children seem to have such large eyes: their skull is smaller than an adult, but they have the same size eyes. The only large-scale change to your eyes over the years is a slight shift in flexibility of different tissues (resulting in various vision issues), excluding serious degenerative issues.
"Stumble before you crawl"
Argus is a *giant*, not a God, in greek mythology.
He did have 100 eyes though. "He was thus a very effective watchman, as only a few of the eyes would sleep at a time; there were always eyes still awake.", as the Wikipedia notes
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IIRC the resolution of the eye is approxmately 0.3x10^-3 radians (in both directions), based on the optics of the eye lens. The resolution of the rods and cones themselves may be lower.
Scientific American Frotntiers, the PBS science show hosted by Alan Alda, recently did a segment on this technology and how it worked for a man who was blinded as an adult. The other segment was on a deaf girl who received a cochlear implant.
A squid eating dough in a polyethylene bag is fast and bulbous, got me?