Visual Implants...

When I was still in grade school in the 80s, there was much talk of what the future may hold technologically. One prediction was that visual and auditory implants would some day be available for blind and deaf people respectively.

Well, deaf people have cochlear implants now. Why don’t blind people have anything yet?

Technology now gives us cell phones we can talk to. When will we get visual implants too?

I’m not talking about something as grandiose as the “VISOR” implant of Geordi Laforge of Star Trek: TNG fame. But surely something that could deliver a poor black and white picture should be available by now.

Well?

:):):slight_smile:

There’s at least some available technology along those lines.

Intraocular lenses are available to replace natural lenses in cases of cataracts and some other conditions.

Or are you thinking of some kind of electronic device, like a digital eyeball-camera, direct-wired into the optical nervous system?

ETA: Here’s another cite: An article in USA Today on some sort of contact-lens-like implant.
http://www.usatoday.com/news/health/2004-09-30-contacts-usat_x.htm
(Article from Sept. 30, 2004.)

There are some research streams with interesting potential - some functional mapping of the visual cortext has been achieved - to the extent that the brain can be scanned and a very crude representation of an observed image can be extracted from the brain (i.e. we can pull a picture of something you’re looking at right out of your brain).

And there have been experiments where a grid of electrodes is implanted in the visual cortex of blind people and they have been able to ‘see’ patterns sent to it.

So in theory, it’s possible to do this. The problem is that it involves implanting things in the brain, and doing that without causing additional damage.

There’s a treatment where they use a person’s tooth, insert a camera into it and mount it in the eye socket, I think. I guess cures depend on the cause of blindness.

Because it’s easier to correct vision by lasering bits off your eyeball than by grafting something on to it.

ETA - Obviously lasers are not much help to someone who’s totally blind, but a lot of people have eyesight that’s bad enough to qualify as “legally blind” while still being able to see a bit. And laser eye surgery can help such people.

There have been trials of a couple of different retina implants for the blind e.g. http://retina-implant.de/en/news/detail_en.aspx?strID=34.
Obviously they are very low resolution and just black and white at the moment.
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Actually, I remember the first trial on a human of this tech at least 5-6 years ago. And each time it’s made the news since, it has appeared as though there has been no improvements to resolution or any other features since the last time.

I’m sure it has progressed, it’s just that news bulletins and press releases are poor at conveying what devices don’t do well yet, which makes it hard to ascertain what rate of progress is actually being achieved.

It’s like how washing powders always claim perfect results…so how can this new formula be an improvement?
</digression>

The cochlea is a much simpler structure to stimulate in a meaningful way than the retina.

I don’t think that’s quite correct - I believe you’re referring to the procedure described here, which involves reconstruction of the eye using grafted tissues (including a tooth), but no camera.

I really hope this isn’t a “needs answer fast” question arising from unsafe viewing of the transit of Venus yesterday…

I assume you’re joking. But no, I didn’t even go outside and look at it. I just followed the event on tv. BTW, to answer the other question, I am talking about an electronic implant that allows the totally blind to see. Not just “Intraocular lenses”.:slight_smile:

Besides the aforementioned issues with getting a retinal implant to work properly, there are also different reasons for severe vision loss/blindness. If the optic nerve is damaged (due to severe, uncontrolled glaucoma, for instance), no microchip will work because the data won’t be transmitted to the brain. Endophthalmitis (infection inside the eye) may cause damage to enough parts of the eye (optic nerve among them) to similarly prevent it from working - assuming the doctors can even save that eye. If the eye is severely damaged due to trauma but salvaged, the damage caused may not be fixable with a retina-based solution.

The retina is a very complex organ, and not fully understood. There is a lot more too it than the light sensitive receptor cells. It is also a dense, 3-layered neural network, and has been described as more like part of the brain itself, rather than a straightforward sense organ. Quite a lot of the processing of the visual input goes on within the retina itself. In rats (for just one example) it has been shown that the retina itself can distinguish object motion from motions of the image across the retina due to eye or head movements, and sends a different visual signal to the rat’s brain accordingly. Whether it is the same for humans is hard to say, as the relevant experiments would be unethical, but there is no doubt that a plenty of processing of this general type goes on in human retina too. What gets sent back to the brain is not a picture or movie (although it has been described, rather metaphorically and inaccurately, as being like about 12 different, simultaneous movies, each dealing with different aspects of the visual environment), but something far more complex, and already partially analyzed.

As such, building an artificial retina that could do anything even close to what the natural human retina does, would be way beyond current technological capabilities, even if we knew (which we don’t - and it is not easy to find out) exactly what pre-processing the human retina does.

There was a guy on my bus who wore a cybernetic eye. He had some doodad implanted in his eye(s), and a special pair of sunglasses that had a little battery powered camera. The glasses would send image data wirelessly to the retinal implant, processed via a little computer.

I asked him about it and he said part of the challenge was miniturizing everything (battery, computer) enough not to be cumbersome/unreliable. He said the image he perceived was very simple- shaped and sillohuettes. But with a cane, it was enough to allow him to get around.

So…I gave a link for one kind of retinal implant which is currently being trialled, and it’s not the first such device.
It’s a far cry from 20/20 vision, but the point is visual implants are much closer to being a reality than some of the posters in this thread seem to realize.

If you’re talking about the research I’m thinking of (Kay et al.?), it’s a lot more complex than that, and less SF. They essentially measure the activity of aspects of hundreds of images, and can correlate the activity of a new image to their past data to figure out which one(s) the new image resembles, and reconstruct a low-resolution prediction.

This is almost always done in epileptic people who are already getting brain surgery. An implanted electrode will not be a huge detriment if they’re already getting sliced up.

I think this is the glasses thing people are talking about: Scientific American Frontiers. It’s from a couple of years ago and a low resolution image (just like the video they give you!). Maybe there is better stuff today. There is also a cochlear implant section.

Is there any way to keep an eye “alive” outside a human body?

And if so, could we then tap somehow into the optic nerve and observe the output?

This way we’d have a black box scenario we could use to study possible implants.

Assuming it’s actually working as reported and continues to show results. I saw results from a similar trial, similar device, same diagnosis, 10 initial subjects, promising initial reports. The trial was opened up to admit more subjects, and the results turned out abysmal. No significant improvement. The whole thing was shelved. This was a decade or so ago; hopefully the company running this latest trial has better results, because there really aren’t treatments for retinitis pigmentosa.

Sigh.

No, but even if we could, the results would not be nearly as meaningful as you as you assume. The eye is not a passive receiver and retransmitter of images, it is constantly in motion: motion that is controlled, at a very fine level of detail, by the brain. Much, probably most, of the important information that the eye extracts from the visual scene comes from the way that features such as edges in the retinal image move over the receptor cells when the eye moves, and it is being moved deliberately so as to extract the information that the brain needs. If the retinal image is stabilized artificially on a person’s retina, they very quickly (in less than a second) cease to see anything at all. The primitive eyes of some organisms do not form images at all, they are just light sensitive cells, but in order to be useful the animal has to keep them in motion. Visual information comes from changes in visual stimulation, mostly changes induced by motion of the (sophisticated or primitive) eye. People whose eye muscles become paralyzed learn to make continual, small jerky movements of their head, to compensate for the lack of movement of the eyes in their sockets. They need to do so in order to be able to see.

So no, an extracted eye in a laboratory would not tell you much about how vision really works, not unless you knew how to move it appropriately. Without motion, there would very quickly cease to be any signal (or any meaningful one) in the optic nerve. Vision needs to be understood as a system, that involves not only the eye and the visual processing parts of the brain, but also the eye muscles and the parts of the brain that control its motion.

This, as such, is not a problem for retinal implant makers, because the implants are made to be put in a living eye that can move normally, but it does mean that experiments on an extracted eye on a lab bench will not take us very far (not much further than we are already) towards building an artificial retina that will do the job that a natural one does. To be able to do that, we need to understand how the eye functions as part of the whole visual system.

Ah yes. The tooth seems to be used to hold a lens without rejection. I must have combined it with another procedure with a camera.