Artificial Eye

   A visual prosthetic or bionic eye is a form of neural prosthesis intended to partially restore lost vision or amplify existing vision. It usually takes the form of an externally-worn camera that is attached to a stimulator on the retina, optic nerve, or in the visual cortex, in order to produce perceptions in the visual cortex. Visual percepts are the final product of a rich interplay of stimulus processing that occurs without the intervention of one's consciousness. While this is a fascinating issue to consider, especially as it pertains to the philosophical and practical definitions of ideas like the "self," the converse is equally interesting to me. In this modern era of exploding technological ingenuity, the sum of which is a product of the conscious brain, increasingly more opportunities exist for the brain to design the input it receives. One method by which this occurs is observable in the treatment of visual pathologies. A development of particular interest to me is the use of visual prosthetic devices in the treatment of some forms of progressive blindness. Research in this area raises numerous conflicts within the realm of bioengineering, but promises, at least, to challenge the boundaries of current microtechnology and instigate further integration of the rapidly expanding fields of electronics and medicine.
                         The goal of retinal prosthetic proposed by the collaborators is to bypass degenerate photoreceptors by providing electrical stimulation directly to the underlying ganglion cells. The ganglion cell axons compose the optic nerve, which travels from the eye and terminates in various regions of the brain, where the combined input is processed along multiple routes and ultimately results in the experience of sight . Ganglion cell excitation will be accomplished by attaching a two-silicon-microchip system onto the surface of the retina, which will be powered by a specially designed laser mounted on a pair of glasses worn by the patient . This laser will also be receiving visual data input from a small, charge-coupled camera, whose output will dictate the pattern intensity of the laser beam . The laser's emitted radiation will be collected by the first microchip within the eye on an array of photodiodes and transferred to the second chip, which will be responsible for electrically stimulating a set of retinal ganglion cells via fine microelectrodes . Because the ganglion cells in a healthy retina are stimulated by photoreceptors, this activation process is designed to mimic the electrical activity within a retinal ganglion cell corresponding to a visual stimulus, with the hope that some measure of sight can be restored to individuals with faulty photoreceptors.

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