In a medical first, researchers have streamed Braille patterns directly onto a blind person's retina, allowing him or her to read letters and words visually, with almost 90% accuracy. Developed by researchers at Second Sight, the headset-like device is set to revolutionize the way degenerative eye diseases like Retinitis Pigmentosa are treated.
To help us better understand the breakthrough and its implications, we spoke to Thomas Lauritzen, Senior Research Scientist at SMP and lead author of the study.
"It's basically a cochlear implant," he tells io9, "but for the eyes."
According to Lauritzen, a cochlear implant circumvents dead hair cells on the inner ear that respond to acoustic signals, by having cells measure sounds as vibrations. The Argus II device, on the other hand, circumvents photoreceptors, the cells that measure light.
"It just so happens that the cochlear implant is about 30 years ahead of the retinal prosthesis," he told us.
Rethinking Argus II
For the experiment, Lauritzen re-worked the way the Argus II normally functions — an ocular neuroprosthetic device that has already been implanted in over 50 patients. Primarily intended for those with Retinitis Pigmentosa, an inherited degenerative eye disorder, the device helps the visually impaired to see color, movement, and objects.
The system works — but it's not perfect. Visual cues, such as letters and short sentences, tend to be cumbersome to read, resulting in unacceptably slow reading times. So in an effort to create something more efficient, the researchers considered a more tried-and-true means of communication: visual Braille.
To make it happen, Lauritzen and his team implanted a 10x6 electrode array directly onto the patient's retina, which was connected to a tiny video camera mounted on a pair of glasses. The system also taps into a wearable computer that processes the video and regulates the strength of the current sent to the electrodes in real-time.
Interestingly, Braille also works in accordance to a grid system. It's essentially a 3x4 array of six dots that represent individual letters.
So, for the Argus II, a grid of six electrodes were chosen from the 10x6 grid. The researchers then stimulated groups of these electrodes — bypassing the camera and going directly to the retina — to create a visual perception of the letters in Braille. So instead of feeling Braille with his finger tips, the patient could actually see the succession of Braille symbols streaming onto his or her retina.
And the results were incredibly encouraging. "For this specific visual Braille project," says Lauritzen, "we were able to increase reading speeds by more than 20-fold."
In terms of specifics, the scientists were able to create two to four letter words in an open-choice reading format. The patient was able to identify 89% of the single letter, 80% of the 2-letter, 60% of 3-letter, and 70% of 4-letter words.
Moving forward, Lauritzen is hoping to get FDA approval for the device in the United States. The Argus II is already commercially available in Europe (CE approved).
"We are continuously working to improve future versions of the device," he told us. "This is basic research that offers one possible future addition to the system."
The entire study can be found at Frontiers in Neuroprosthetics
Images: Second Sight.