Slashdot Mirror
Bionic Retinas Give Patients Sight
The Noof writes "
Yahoo News is running a
story about patients who have been given partial sight thanks to implants
of silicon-based bionic retinas.
" The article notes that the implant is having a "rescue effect" on the other components of the retina, restoring cells around the implant and making them useful again." Amazing stuff.
Yes, it would be awful if Yahoo got slashdotted, wouldn't it? Better post the article, just to make sure.
May we never see th
While this indeed is a great innovation, we must remember that this has only been tested by people affected by retinitis pigmentosa. Whether the optical implants can be used to restore sight for people from eye injuries or other diseases remains to be seen.
A lowdown on retinitis pigmentosa can be found here.
Let's build on that. How dense could the sensors get before the optical limits of the eye would become the bottleneck?
Also, since these things are using the photo-voltaic effect to generate the electrical impulse, isn't there a limit to how well they would work in low light? Can that limit be overcome? Could they build units that grabbed inductive power from a transmitter in your glasses to overcome that problem, or maybe even allow super night vision? Will future soldiers be encouraged to get such implants? On the opposite side of that equation, would they allow you to look at the sun without being damaged?
For all intensive purposes, "whom" is no longer a word. That begs the question, "who cares"?
I think you underestimate just how good human biological vision really is. It is easy to think at first that rods and cones are just like CCDs or pixels or whatever. It is far more complicated than that. In fact, there is extensive research that demonstrates that you can see in higher resolution than should be optically possible. The reason this works is complicated, but basically comes down to the fact that there is an immense amount of inter-cellular interpolation going on. It can be modeled simplistically as an array of voltage sources.
A good starter paper might be the classic "What the Frog's Eye Tells The Frog's Brain" by McCullough, Pitts and Lettvin. (From MIT's RLE Lab in the 50's) More recently, Marr's stuff is supposed to be very good.
Nonperiodic Central Trajectory
OK, I am one of the scientists here at ARVO (Association for Research and Vision in Ophthalmology), and was present at the presentation of Dr. Chow.
I for one would love to believe in the results, but I have not seen any real scientific proof that these things work as advertised. While the video of patients was impressive and touching, there is very little hard science behind the development of the bionic retina and how it is integrating into the retinal environment. The only thing that everyone appears to be reporting on is that the chip is not rejected. And there are other more fundamental issues at work. For one, the silicon retinas require the equivalent of 3X's the brightness of the sun to activate the device and for realistic performace, they would require an external power source. The other issue is that the retinal circuitry that they are placing this bionic implant onto is severely degenerated and remodeled in these patients and may continue to degenerate further, thus complicating matters. That said, there is some indication that the surgery itself may cause some retinal rescue, not the implant. This is something they have not done control experiments on. Furthermore, the generation of low voltage current from the implant in the retina may be promoting retinal recovery of sorts while the silicon retina may not be doing anything for vision itself.
We are still a looooong ways away from the idea of a bionic retina and I think that retinal implants will actually be the least effective method in the long run. Gene therapy, viral infective methods, stem cells, and post retinal bionics will probably work optimally sooner.
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