For many researchers hoping to produce a technological cure for blindness, there’s been one big bottleneck—the current method of generating curved image sensors simply can’t compete with the human retina, which packs more than 100 million photoreceptors in the back of a single human eye.
But recent advances by a team at Hong Kong University of Science and Technology could move development of the bionic eye forward more quickly than ever. And in a commentary published May 20, 2020, in the News & Views section of the journal Nature, a University of Wisconsin-Madison engineer puts those advances into context.
The Hong Kong team made several breakthroughs, including developing a curved retina, something Hongrui Jiang, a professor of electrical and computer engineering at UW-Madison and an optics expert, says was the holy grail for image sensors over the last 20 years.
The Hong Kong researchers achieved the artificial retina by developing a new method for growing perovskite nanowire photosensors in nanoscale pores, creating a curved photosensor array with a density even higher than that of photoreceptors in the human retina.
Though the process of producing this artificial retina is currently very costly and time-consuming, Jiang, who served as a peer reviewer for the Hong Kong team’s research, says the work is taking the world one step closer to true artificial vision. “The main application for the artificial retina is to cure blindness,” says Jiang, “but there are other applications, like in robotics. This will fulfill some of the sci-fi stuff you see in the movies. R2-D2 will soon look more like a person than a robot!”
The big hurdle left in creating a true bionic eye lies in the brain. While producing the new type of sensor was difficult, Jiang says another challenge will be in getting the signal from the bionic eye to the brain in a format it can process.
Jiang hopes that his own research can also help with the development of bionic eyes. The new bionic eye mimics the anatomy of a mammalian eye, or camera-type eye, in which one large lens focuses light on a densely-packed, curved retina at the back of the eyeball. Jiang and his team have made several high-profile breakthroughs in mimicking compound eyes, similar to insect eyes, in which dozens or hundreds of smaller eyes work together to produce an image. In that system, each eye produces less visual information, but together they have a larger field of view and better motion detection than camera-type eyes.
But Jiang believes it is possible to combine the two types of eye to take advantage of the benefits of both. His current research involves using elements from compound and camera-type eyes to improve visualization for camera-guided laparoscopic surgery, which requires both high-resolution and a large field-of-view images in tiny spaces.
The new bionic eye, he says, is bringing that vision and many other applications closer to reality. “With breakthroughs like these in the last decade with bionic camera eyes and in artificial compound eyes, in maybe another decade we’re going to see wide daily use of both types of bionic eyes,” he says.
Jiang is the Lynn H. Matthias Professor in Engineering and Vilas Distinguished Achievement Professor in electrical and computer engineering at UW-Madison.
Author: Jason Daley