Bionic eye may restore sight to the blind

Robin Wulffson MD's picture
Argus II, blindness, bionic eye, retinitis pigmentosa, macular degeneration
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Loss of vision is a devastating disability and much research has been focused on restoring sight to the blind. Restoring sight to the blind is a particularly challenging problem; however, a new technology that combines an eye implant and video-camera-enabled glasses may soon receive approval of the US Food and Drug Administration (FDA).

For decades, scientists have attempted to develop a bionic eye and hundreds of millions of dollars have been spent on research. A device designed to help individuals with a rare eye condition is awaiting FDA approval. It is known as the Argus II and is manufactured by Second Sight Medical Products Inc. of Sylmar, California. Other researchers, including at the Massachusetts Institute of Technology (MIT) and Stanford University, are also hard at work on what they believe are even more sophisticated versions of the Argus II. The Second Sight product uses what is known as a retinal prosthesis; it bypasses the dead or damaged cells in the eye needed to detect light. Instead, the Argus II reroutes visual data via the implant to parts of the eye that still function. It employs a video camera embedded in a pair of eyeglasses to collect visual input in the form of light and transmit it to the implant as an electrical signal.

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The Argus II is already available in Europe. If it receives FDA approval, it would be the first retinal prosthesis to be marketed in the United States. The individuals most likely to benefit from it are those with retinitis pigmentosa, a rare disease that damages and kills the cells in the retina (a tissue layer at the back of the eye) that process light. Affected individuals experience progressively blurred vision until they are unable to see at all. Approximately 100,000 people in the US have the condition. According to Second Sight, another group of individuals who may benefit from the Argus II are those with severe macular degeneration. This is an age-related disease that damages the part of the eye that perceives fine detail.

The various retinal prostheses under development all use video cameras to send light information to chip implants. Most of them use the data to trigger electrodes in the chip to stimulate pixels of light on the retina, which are then processed normally by the brain as images. The technology tested to date lets the wearer primarily see in black and white. It is most useful for seeing sharp contrasts, such as the painted white line of a crosswalk on a dark road. However, the researchers hope that they can improve the detail to eventually enable color vision in its wearers.

Reference: Second Sight

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