- Retinal implant
A retinal implant is a biomedical implant technology currently being developed by a number of private companies and research institutions worldwide. The implant is meant to partially restore useful vision to people who have lost theirs due to degenerative eye conditions such as
retinitis pigmentosa ormacular degeneration . The technology consists of an array of electrodes implanted on the back of theretina , a digital camera worn on the user's body, and a transmitter/image processor that converts the image to electrical signals and beams them to the electrode array in the eye. The technology, while still rudimentary, would allow the user to see ascoreboard type image made up of bright points of light viewed from about arm's length. While development is currently aimed only at the disabled, this technology, could revolutionize the personal computing andcyborg industries once perfected.There are two types of retinal implants currently showing promise in clinical trials:Epiretinal Implants (on the retina) and Subretinal Implants (behind the retina).
Epiretinal Implants sit on top of the retina, directly stimulating
ganglia using signals sent from the external camera and power sent from an external transmitter, where Subretinal Implants sit under the retina, stimulating bipolar or ganglion cells from underneath. Some subretinal implants use signals and power from external circuitry, while others use only incident light as a power source and effectively replace damagedphotoreceptors leaving all other structures within the eye untouched.However, due to a lack of an external power source, the image signal in this second type of subretinal implant may not be as strong as that given by an externally powered epiretinal or subretinal implant.External links
* [http://www.bostonretinalimplant.com/ Boston Retinal Implant Project]
* [http://www.retina-implant.de/en/about/ Retina Implant - leading company developing the subretinal implant]
* [http://www.io.mei.titech.ac.jp/research/retina/ Japan Retinal Implant Project]
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