"During the two-hour operation under local anaesthetic, patients had jelly-like substance removed from their eye to make space for the implant, which was inserted under the centre of their retina. About a month later, once the eye had settled, the chip was activated. Patients were given augmented-reality glasses containing a video camera connected wirelessly to a small computer, which was attached to their waistband. The video camera projected the scene to the chip, which converted it into an electrical signal, passing through the optical nerve cells into the brain, where it was interpreted as vision...."
From "Vision restored in blind patients with revolutionary microchip/A tiny retinal implant connected to smart glasses allows patients who had completely lost their central sight to see again" (London Times).