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VR Interfaces: Boston Retinal Implant Project


Overview of Boston Retinal Implant Project
The 'virtual light' class of retinal displays, are perhaps unique in the display industry, because they don't actually display anything. The entire concept is built round bypassing the eye entirely, and dropping visual encoded information directly into the optic nerve. This of course has two fold benefits.

Firstly, it bypasses any damage or degeneration in the eye completely, eliminating partial or total loss of visual acuity from the equation - essentially, it allows sight even without eyes.

Secondly, for applications such as VR, it removes the possibility of eye-strain by repeatedly focusing at different wavelengths of light to compensate for perceived distance on a 2D screen. It does this by bypassing the use of the eyes entirely. They can still focus or unfocus, but because the correct information reaches the brain regardless, there is no straining to reach the appropriate focus level, as occurs constantly with all monitor systems.

The Boston retinal implant, is a type of interface along these same lines, that was actually inspired by the cochlear implant for the ear. In other words, the attempt to restore full function to an organ that is damaged beyond its own ability to heal.

Created by MIT, this eye implant is designed for people who have lost their vision from retinitis pigmentosa or age-related macular degeneration, two of the leading causes of blindness. The retinal prosthesis would take over the function of lost retinal cells by electrically stimulating the nerve cells that normally carry visual input from the retina to the brain.

"Anything that could help them see a little better and let them identify objects and move around a room would be an enormous help," says Shawn Kelly, a researcher in MIT's Research Laboratory for Electronics and member of the Boston Retinal Implant Project.

Led by John Wyatt, MIT professor of electrical engineering, the team recently reported a new prototype that they hope to start testing in blind patients within the next three years.

As with all devices of this type at the moment, it works on something of an augmented reality meme. An AR interface with cameras embedded in what would look to be a normal pair of spectacles, would transmit images to the microchips embedded in the ocular cavity, attached to the outside of the eye. The spectacles also house a coil capable of keeping the microchip powered. A literal case of no sight without the spectacles, bringing the old cartoon jokes full circle.

One of the biggest challenges the researchers face is designing a surgical procedure and implant that won't damage the eye. In their initial prototypes, the electrodes were attached directly atop the retina from inside the eye, which carries more risk of damaging the delicate retina. In the latest version, described in the October issue of IEEE Transactions on Biomedical Engineering, the implant is attached to the outside of the eye, and the electrodes are implanted behind the retina.

That sub retinal location, which reduces the risk of tearing the retina and requires a less invasive surgical procedure, is one of the key differences between the MIT implant and retinal prostheses being developed by other research groups.

The implant is not yet at the stage of human trials. Implantation in pigs is ongoing.

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