Millions of people in the world are affected by progressive vision-loss diseases or complete blindness, in what is one of the largest epidemics to date. Vision is lost either in accidents, or because of diseases and old age. That is to say, individuals with diabetes may develop diabetic retinopathy, while seniors in Europe and North America are very prone to gradually losing their sight on account of age-related macular degeneration (AMD). For all these persons, opticians and electronics experts are trying to develop advanced prosthetic devices, able to restore at least partial vision in one or both of their eyes.

Currently, the main line of research is the one based on harnessing the power of electrical impulses transmitted from the brain. Except for the ones that have been born blind on account of nerve degeneration, the optical tracts of people with vision loss or acquired blindness are perfectly fine, as only their retinas are usually damaged. This means that the electrical current sent by the brain can travel on its usual pathway to the retina, but doesn't have the necessary cells to transform light into impulses.

And this is where modern microelectronics comes in. For millennia, ancient Chinese medicine practitioners have known that the human body is circulated by a weak electrical current, and that it has been this current that has made us “tick.” Centuries later, Western practitioners have come to the same conclusion, and have suggested that harnessing this electricity may make interfacing between humans and machines possible.

That has been, indeed, the case, as experts from around the world have devised ways of hooking up prosthetic limbs to a person's brain, via a computer. Sensors on the brain would identify the impulse generated by the individual's desire to move an artificial arm, for example, and would convert that small current into code lines, which would then move the robotic arm.

But researchers working with vision restoration techniques cannot afford to have such a delay in their systems. Instead, they are advocating a direct interface, one in which, for example, a chip is inserted inside the eye, which communicates directly with the optical nerve and then the brain. The chip would also be connected to a camera mounted on a pair of glasses. The system does not guarantee a perfect vision, but allows blind people to identify shapes and a little bit of color.

Another approach involves creating microchips, to be placed directly on the retina, which would instantly transform the light that enters the eye into electrical current, and feed these impulses directly to the visual nerve. This method only allows people to see in black and white, and only larger objects are somewhat visible.

However, with the invention of modern electronic materials, such as carbon nanotubes, it may soon become possible to have more advanced chips able to process the images in a similar manner to the natural retina, and then feed them directly to the brain.