Daily Times

The eye, as detailed in a paper published in the prestigious journal Nature today, is in essence a three-dimensional artificial retina that features a highly dense array of extremely light-sensitive nanowires.

Researchers say they’ve created a proof-of-concept bionic eye that could surpass the sensitivity of a human one.

“In the future, we can use this for better vision prostheses and humanoid robotics,” researcher Zhiyong Fan, at the Hong Kong University of Science and Technology, told Science News.

The human eye owes its wide field of view and high-resolution eyesight to the dome-shaped retina — an area at the back of the eyeball covered in light-detecting cells. Fan and colleagues used a curved aluminum oxide membrane, studded with nanosize sensors made of a light-sensitive material called a perovskite (SN: 7/26/17), to mimic that architecture in their synthetic eyeball. Wires attached to the artificial retina send readouts from those sensors to external circuitry for processing, just as nerve fibers relay signals from a real eyeball to the brain.

The artificial eyeball registers changes in lighting faster than human eyes can — within about 30 to 40 milliseconds, rather than 40 to 150 milliseconds. The device can also see dim light about as well as the human eye. Although its 100-degree field of view isn’t as broad as the 150 degrees a human eye can take in, it’s better than the 70 degrees visible to ordinary flat imaging sensors.

In theory, this synthetic eye could perceive a much higher resolution than the human eye, because the artificial retina contains about 460 million light sensors per square centimeter. A real retina has about 10 million light-detecting cells per square centimeter. But that would require separate readings from each sensor. In the current setup, each wire plugged into the synthetic retina is about one millimeter thick, so big that it touches many sensors at once. Only 100 such wires fit across the back of the retina, creating images that have 100 pixels.