Retinal implant offers hope for blind, extends vision to infrared

A team of Chinese scientists has unveiled a revolutionary retinal implant that may not only restore sight to the blind but also grant them the ability to see infrared light, a spectrum beyond normal human sight.

The study, published on Friday in the journal Science, demonstrates how a mesh of ultra-thin tellurium nanowires can replace damaged photoreceptors in a blind mouse's eye, and convert near-infrared light into electrical signals that the macaque brain, a non-human primate model, can interpret as vision.

The new technology's feasibility and strong safety profile mark a milestone in the development of artificial vision, which could prove invaluable to 200 million patients worldwide who are living with blindness or retinal disease.

The team from Shanghai tested their device in blind mice, which subsequently regained reflexes in the pupil and evoked neuron firing in the visual cortex. They performed almost as well as normal mice in visual pattern recognition tests.

More significantly, the device was successfully implanted in macaque monkeys, where it demonstrated both safety and the ability to detect near-infrared 1,550-nanometer light, according to the study.

In patients with severe eye diseases, such as macular degeneration, infrared vision could, in principle, aid vision in low light and darkness. The device could potentially provide significant advantages in low-light conditions.

The nanowire mesh is remarkably thin -- about ten times thinner than previous artificial photoreceptors -- making it easier to implant and more compatible with the delicate structures of the eye, said Zhang Jiayi from Fudan University, one of the lead researchers.

The retinal implant might be a game-changer since a single minimally invasive, reversible procedure restores natural vision without bulky glasses or frequent charging, according to the study.

The team designed a nanowire for the retina based on tellurium, a silver-white, light-sensitive element that's used as a semiconductor, and interlaced them into an implantable lattice network.

It showed good biocompatibility and did not require external power sources, said the journal's editor Mattia Maroso.

This successful animal study paves the way for future human trials, and offers a safer, more effective and wider-spectrum solution than existing technologies, said the researchers.

It could "substantially improve the efficacy of retinal neuroprostheses in restoring vision in blind and visually impaired individuals," said Maroso.