4. Conclusion: new generations of implants

The basic principle of a visual prosthesis is to capture an image of the patient's visual scene, then translate it into temporally and spatially adapted stimulation signals. In this way, the visual scene is transcribed at the electrodes of an implant, which can be placed theoretically anywhere in the optical pathway, so as to short-circuit existing damage within it. Scene information is pixelated and transmitted to the electrodes from an electronic circuit or photodiodes, which convert light intensity directly into electrical stimulation signals. Although total restoration of vision is a long way off, rudimentary vision is now possible with the help of electrical stimulation, improving the quality of life of some patients whose vision is otherwise non-existent or extremely poor.

The photoreceptor region is the most obvious target area, as it simply replaces the...