It is now several years that researchers are studying ways to restore sight to people who lost it. In a way, amazing results have been reached; retinal implants have been approved by FDA and European counterparts and a few patients have got a limited, but useful sight restored.
So far retinal implants are using a camera that is capturing light and a microcomputer to convert this into signals that are sent wirelessly to an implant on the retina that in turns stimulate the optical nerve. The problem with this setting is the need to wear a camera and the very low resolution that can offer (although the resolution has been increasing over time we are still talking about hundreds of pixels versus a normal retina that has an equivalent of 8 million pixels (roughly speaking, taking into account cones and rods and their equivalent resolution).
Now a joint team of researchers at the Tel Aviv University, Jerusalem University Center for Nanoscience and Nanotechnology and at the Newcastle University has published a paper where they describe the way to create a smart material that can be used as an artificial retina.
They have been able to create a wireless, light sensitive flexible film using semiconductor nano rods and carbon nanotubes. The film has been tested on a damaged chick retina that was no longer responding to light stimuli. With the film flanking it they have demonstrated neural activity as response to light detection.
This approach can result in much greater resolution since the nanotubes can be clustered in lumps the size of retinal cones and rods. Additionally, they require very little energy, hence their dissipation can be in the same range of the ones of the retinal activity (whilst a normal silicon chip requires much more energy resulting in heat dissipation that would kill the nerve termination. This is why in current implant the chip has to stay outside of the eye and only few signals are transmitted to the implant).
There is clearly a lot of work needed to "replace" a damaged retina with an artificial one but it is now becoming more an engineering progress than a scientific one and we know that technology will keep progressing. An artificial retina, indeed, now is in sight.