A tiny camera receives visual information from the environment and transmits signals to a bionic contact lens.
By Dan Even, HAARETZ
Israeli scientists have developed a technology that may enable people who are blind from birth to see, with the help of a bionic contact lens.
The new technology, developed by a team at Bar-Ilan University, has yet to receive approval for clinical trials, but its feasibility is currently being tested on seeing individuals, with the aid of a model simulating the bionic lens.
The technology consists of a tiny camera that receives visual information from the environment and transmits signals to a bionic contact lens. The lens passes the signals via electrodes to the cornea and from there to sensory brain areas, generating a stimulus that simulates visual information.
“This technology is good news for humanity, especially in bringing sight to people blind from birth without requiring surgery or damaging other vital senses or organs,” says Prof. Zeev Zalevsky, head of Electrical Engineering and Nanophotonics at Bar-Ilan University, who headed the research team.
In recent years, several companies around the world have developed a bionic eye, but all of them rely on a technology which is of little help to those who are congenitally blind. This system, which bypasses the retina, is intended for those who suffer from retinal degeneration. It consists of a tiny camera implanted in the eye that transmits electric signals directly to the sight nerves attached to the retina, bypassing the retina and generating visual stimulation.
In addition, that system is invasive and requires surgery. It also depends on the stimulation of brain areas that process sight, which are developed in childhood. This makes it unsuitable for those who are blind from birth, since those areas of the brain are not developed in congenitally blind people. The U.S. company Second Sight, the German company Retina Implant AG, the Australian company Bionic Vision and the Israeli company Nano Retina all use this technology.
The visual resolution in existing bionic eyes is about 16 pixels, compared to a million (1 mega) pixels in a normal eye. This enables people with bionic eye implants to distinguish between light and darkness and shadows, but not to make out entire objects or letters, or to be independently mobile.
In contrast, the new Israeli technology is non-invasive and is intended to provide sight to the congenitally blind.
“The new technology attempts to deal with the problems of existing bionic eye technologies to enable even people who are blind from birth, in whom the brain region that processes visual information is not developed, to see,” explains Zalevsky.
The bionic lens stimulates the corneal nerves in the eye’s external part, which are connected in the brain to areas that process sensory information.
The technology consists of a tiny camera with an image compressor and an electric signal amplifier located outside the patient’s body and can be attached to his eye glasses or to a cellular device. Super resolution techniques are used “to encode an image of numerous pixels and compress it into few pixels,” explains Zalevsky.
“The encoding enables compressing static visual sights, reducing the pixels yet allowing transmission of visual information similar to a healthy person’s vision,” he says.
The compressed information is transmitted, after being electrically amplified, from the minute camera by wireless technology to a bionic contact lens in the eye. The proposed lens will have some 10,000 tiny electrodes enabling cornea stimulation. “The cornea is the richest eye part in sensory nerves and has tens of thousands of sensory points to which the tiny electrodes on the lens can connect with,” says Zalevsky.
It’s already possible today to place tiny electrodes, even opaque ones from metallic material, on contact lenses that look transparent. The electrodes stimulate the cornea’s sensory points by transmitting tension, without direct contact with the cornea, due to the compressed signal amplification in the external apparatus.
The stimuli are passed from the cornea via the nervous system to various brain regions that process visual information.
“In this way even a person who is blind from birth can see. In blind people, the sensory areas that receive the information from the cornea are developed, like regions enabling them to read Braille with the sense of touch,” says Zalevsky.
He says the new technology is like “a Braille lens that enables blind people to see in a way similar to Braille reading.”
The Bar-Ilan technology has yet to be approved for clinical testing. But in the last few months the system’s feasibility has been tested on 10 seeing subjects with a model simulating the bionic lens, which transmits stimuli to the finger rather than the cornea.
The scientists have taught the testees to decode simple images and then to transmit, with finger signals, images received by an external camera.
At this state the visual stimulus among the subjects enables spatial vision in black, white and gray, in low 100-pixel resolution.
“But the actual lens will consist of 10,000 electrodes that will enable receiving visual images of much higher resolution and perhaps color in the future,” says Zalevsky.
An article about the technology has recently been published in Optical Engineering and the development will be exhibited in the Israel BioMed conference in June.
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