Scientists have developed a new technology that completely bypass the eyeball and sends messages directly to the brain to restore vision to the blind.
Stimulation of the optic nerve was achieved by using a new type of intraneural electrode called OpticSELINE.
The idea developed by researchers from Swiss Federal Institute of Technology Lausanne (EPFL) and Scuola Superiore Sant'Anna in Italy has been described in the journal Nature Biomedical Engineering.
The new technology, successfully tested in rabbits, could pave the way for a new visual aid for daily living.
The concept is to produce phosphenes, the sensation of seeing light in the form of white patterns, without seeing light directly.
"We believe that intraneural stimulation can be a valuable solution for several neuroprosthetic devices for sensory and motor function restoration. The translational potentials of this approach are indeed extremely promising," said Silvestro Micera, a professor at Scuola Superiore Sant'Anna.
If the new technology is proved successful in humans, it will provide a ray of hope for visually impaired people. Around 39 million people in the world suffer from blindness due to reason like genetics, retinal detachment, trauma, stroke in the visual cortex, glaucoma, cataract, inflammation or infection.
"Cuff electrodes are surgically placed around the nerve, whereas intraneural electrodes pierce through the nerve," said Diego Ghezzi from EPFL.
Together, Ghezzi, Micera and their teams engineered the OpticSELINE, an electrode array of 12 electrodes.
In order to understand how effective these electrodes are at stimulating the various nerve fibres within the optic nerve, the scientists delivered electric current to the optic nerve via OpticSELINE and measured the brain's activity in the visual cortex.
They developed an elaborate algorithm to decode the cortical signals.
The researchers showed that each stimulating electrode induces a specific and unique pattern of cortical activation, suggesting that intraneural stimulation of the optic nerve is selective and informative.
As a preliminary study, the visual perception behind these cortical patterns remains unknown.
"For now, we know that intraneural stimulation has the potential to provide informative visual patterns," Ghezzi said.
"It will take feedback from patients in future clinical trials in order to fine-tune those patterns. From a purely technological perspective, we could do clinical trials tomorrow," he said.
With current electrode technology, a human OpticSELINE could consist of up to 48-60 electrodes.
"This limited number of electrodes is not sufficient to restore sight entirely. But these limited visual signals could be engineered to provide a visual aid for daily living," said Ghezzi.
(With inputs from PTI)
