Retinal prosthetics — electronic implants that do the work of damaged or missing light-sensitive cells in blind peoples’ eyes — are pretty amazing, but they remain crude at best because of one key design flaw: The human eye is not a camera with a faulty sensor chip, “but the first stage in a system for understanding the world around us,” writes vision researcher Patrick Degenaar of Newcastle University.
Denegaar’s idea relies on bleeding-edge science.
As he notes, “There are around 50 different types of processing neuron in the retina, and more than 20 types of retinal ganglion cell. So the visual cortex of the brain expects to receive the visual world encoded in a “neural song” of many different voices. Precise coding to reproduce this song is hard to achieve with implanted electrodes and the result is that the patient sees phosphenes “- flashing dots of light -” rather than what we would normally define as sight.”
So what if there were a prosthetic that were designed to more closely approximate this “neural song” right at the source? By teaming up with designers at Superflux, Denegaar has created a concept that would do exactly that. They call it “Song of the Machine.”
Like Revital Cohen’s art installations, “Song of The Machine” takes real-world science and imaginatively pushes it to its limits. Denegaar’s idea relies on a bleeding-edge scientific technique called optogenetics, which can use flashes of laser light to make nerve cells fire on and off at will. As he told The Guardian, the nerve cells become sensitized to the laser light by adding genetically engineered DNA to them:
“Rather than performing highly complex surgery to implant electrodes into a patient’s retina, a solution of a special virus would simply be injected to introduce new genes into the nerve cells. The patient would then wear a headset that records and interprets the visual scene and sends coded pulses of light to the retina. As a single pulse of light can generate a single action potential, the information encoded from the visual scene can be much more in tune with the neural song expected by the visual cortex.”
Optogenetics already works wonders in laboratory animals, and the designers say that Denegaar has prototypes that he hopes to test with visually impaired people in two to three years. But “Song of the Machine” is a glimpse of that future right now. “Early-stage vision will remained restricted, with low resolution,” says Superflux. But if you can see ultraviolet radiation like bees, or in the dark using infrared like the Predator, “restricted” starts to sound more like “awesome.” (On the more practical side, writes Denegaar, “this ‘multi-spectral imaging’ could be used for telling at a glance whether an object is too hot to touch.” Still awesome!)
“Song of the Machine” is being exhibited as part of The Science Gallery’s Human+ show in Ireland, and it’s a great example of how science and engineering illuminate what’s possible while design helps zero in on what’s preferable. And collaborations across all three disciplines, like the one between Superflux and Dr. Denegaar, are the best way we have of bridging the gap between science fiction and science fact.