World's first spherical artificial eye has 3D retina

Date:
June 10, 2020
Source:
Hong Kong University of Science and Technology
Summary:
Scientists have developed the world's first 3D artificial eye with
capabilities better than existing bionic eyes and in some cases,
even exceed those of the human eyes, bringing vision to humanoid
robots and new hope to patients with visual impairment.



FULL STORY ==========================================================================
An international team led by scientists at the Hong Kong University of
Science and Technology (HKUST) has recently developed the world's first
3D artificial eye with capabilities better than existing bionic eyes and
in some cases, even exceed those of the human eyes, bringing vision to
humanoid robots and new hope to patients with visual impairment.


========================================================================== Scientists have spent decades trying to replicate the structure and
clarity of a biological eye, but vision provided by existing prosthetic
eyes -- largely in the form of spectacles attached with external
cables, are still in poor resolution with 2D flat image sensors. The Electrochemical Eye (EC-Eye) developed at HKUST, however, not only
replicates the structure of a natural eye for the first time, but may
actually offer sharper vision than a human eye in the future, with extra functions such as the ability to detect infrared radiation in darkness.

The key feature allowing such breakthroughs is a 3D artificial retina --
made of an array of nanowire light sensors which mimic the photoreceptors
in human retinas. Developed by Prof. FAN Zhiyong and Dr. GU Leilei from
the Department of Electronic and Computer Engineering at HKUST, the team connected the nanowire light sensors to a bundle of liquid-metal wires
serving as nerves behind the human-made hemispherical retina during the experiment, and successfully replicated the visual signal transmission
to reflect what the eye sees onto the computer screen.

In the future, those nanowire light sensors could be directly connected
to the nerves of the visually impaired patients. Unlike in a human
eye where bundles of optic nerve fibers (for signal transmission) need
to route through the retina via a pore -- from the front side of the
retina to the backside (thus creating a blind spot in human vision)
before reaching the brain; the light sensors that now scatters across
the entire human-made retina could each feed signals through its own liquid-metal wire at the back, thereby eliminating the blind spot issue
as they do not have to route through a single spot.

Apart from that, as nanowires have even higher density than photoreceptors
in human retina, the artificial retina can thus receive more light
signals and potentially attain a higher image resolution than human
retina -- if the back contacts to individual nanowires are made in the
future. With different materials used to boost the sensors' sensitivity
and spectral range, the artificial eye may also achieve other functions
such as night vision.

"I have always been a big fan of science fiction, and I believe many technologies featured in stories such as those of intergalactic travel,
will one day become reality. However, regardless of image resolution,
angle of views or user-friendliness, the current bionic eyes are still of
no match to their natural human counterpart. A new technology to address
these problems is in urgent need, and it gives me a strong motivation
to start this unconventional project," said Prof. Fan, whose team has
spent nine years to complete the current study from idea inception.

The team collaborated with the University of California, Berkeley on this project and their findings were recently published in the journal Nature.

"In the next step, we plan to further improve the performance, stability
and biocompatibility of our device. For prosthesis application, we look
forward to collaborating with medical research experts who have the
relevant expertise on optometry and ocular prosthesis," Prof. Fan added.

The working principle of the artificial eye involves an electrochemical
process which is adopted from a type of solar cell. In principle, each
photo sensor on the artificial retina can serve as a nanoscale solar
cell. With further modification, the EC-Eye can be a self-powered image
sensor, so there is no need for external power source nor circuitry
when used for ocular prosthesis, which will be much more user-friendly
as compared with the current technology.


========================================================================== Story Source: Materials provided by Hong_Kong_University_of_Science_and_Technology. Note: Content may be
edited for style and length.


========================================================================== Journal Reference:
1. Leilei Gu, Swapnadeep Poddar, Yuanjing Lin, Zhenghao Long,
Daquan Zhang,
Qianpeng Zhang, Lei Shu, Xiao Qiu, Matthew Kam, Ali Javey, Zhiyong
Fan. A biomimetic eye with a hemispherical perovskite nanowire
array retina.

Nature, 2020; 581 (7808): 278 DOI: 10.1038/s41586-020-2285-x ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/06/200610102726.htm

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