Artificial Vision

“Artificial vision” or “prosthetic vision,” in the therapeutic sense, refers to the restoration of some degree of visual perception to the profoundly blind. In nearly all instances, such therapeutic devices are based on electrically exciting the remaining functional neural tissue within the visual pathway, which replaces the intrinsic signals that can no longer be effectively elicited because of the underlying pathology or trauma. The therapeutic device for restoring vision is generally called a “vision prosthesis.”

Although a variety of approaches for a vision prosthesis design are available, a typical system usually would constitute a light sensing component (e.g., a video camera) to replace the photosensitive elements related to light transduction, an image processing unit to replace the signal processing in the visual system bypassed by the prosthesis, electronic circuitry to generate electrical stimulus waveforms to elicit perceptions of light artificially, and stimulating electrodes placed in close proximity to the target neural tissue to deliver the electric charge. Furthermore, the implanted portion of the system has to be encapsulated properly to ensure longevity and biocompatibility.

At the time of writing, no commercially available product was available to provide artificial vision. However, several major research groups are working toward developing such a therapeutic device. Simple prototypes have been tested successfully in acute and chronic animal trials and more recently in small-scale human trials. Psychophysical studies show that, despite the limited functionality of these prototypes, the recipients can successfully execute some simple visually guided tasks.

Keywords: artificial vision; prosthetic vision; visual system; vision prosthesis; bionic eye; retinal prosthesis; cortical implant; neuroprosthesis; blindness