A CBS News report, After 20 years of darkness, bionic eye helps blind man see, described how technology helped a man who had been blind regain his vision. The ‘bionic eye’ discussed in the article is not an eye, but rather a system comprised of a pair of glasses, a wearable computer and an implant in his retina.
Anthony Andreotolla suffers from retinitis pigmentosa (RP), and began to lose his sight as a teen. By the time he was in his thirties, he was completely blind. Fast-forward 20 years and he has regained partial sight thanks to a medical device designed by Second Sight.
The device, called the Argus, uses a small video camera mounted on a pair of glasses that sends images to the wearable computer. Those images are processed and sent wirelessly to an implant in his eye that in turn passes electrical impulses to the brain.
Patients such as Andreotolla learn to interpret these patterns of light. The images are rough and pixelated. They cannot transmit colour, but rather light pulses. The patterns enable the patients to see shapes and objects, helping these patients navigate their world.
“I don’t see things the way other people do. I see everything in different flashes, lights, shapes,” says Andreotolla. “I can tell the difference between a car or a bus or a truck. I can’t tell you what make the car is.”
Translating the video into light pulses on the implant
Image processing speed and resolution are key. Since its introduction, the Argus system has gone from a 16-pixel to a 60-pixel implant. The higher the number of pixels providing light pulses to the retina, the clearer the image for the patient. Processing speed is also important since delays in projection to the retina have the same effect as seeing your surroundings on a time delay.
MATLAB was used to develop the image processing algorithms that turn the video stream into light pulses on the retinal implant. Simulink automatically generated and deployed the code onto a digital signal processor.
With increased resolution, patients would be able to identify letters in text. In a study published in the British Journal of Ophthalmology, researchers found multiple blind subjects fitted with the Argus II system consistently identified letters and words using the device.
Over 200 RP patients regain sight
The Argus II, with improved resolution and processing speed, was first used in clinical trials in 2007. Since then, more than 200 patients have received the device in the US and Europe. The first patient in Asia was treated earlier this year.
Second Sight is now working on implanting an array of electrodes on the brain rather than in the retina. According to MIT Technology Review, the device, called the Orion, is a modified version of the company’s current Argus II. It borrows about 90 percent of its technology from the Argus system.
© MathWorks 2017