Microchip Makes Partial Visibility Possible- A Boon To The Blind?
Is it not amazing when you hear that a blind person was able to discern seven shades of gray? A microchip of the size 3mmx3mm implanted under the retina made this miracle possible. This small chip had 1500 light detectors that send a grid of electrical impulses through nerves to generate the image. The implant, a product of 15 years of research, essentially replaces degenerated rod and cone cells in the retina of patients suffering from diseases such as retinitis pigmentosa, a group of inherited diseases that afflict 1 in 4,000 people across the world and is characterized by poor night vision and slow loss of peripheral vision. A thin wire snakes from inside the eye to its edge and then under the skin to a spot behind the ear, where patients can attach a cord linked to a control box that supplies power. Patients can also use the control box to adjust the brightness and contrast of images. In the pilot study, 11 patients received an implant, all of whom had been blind for two to 15 years due to hereditary retinal dystrophy. Five of the 11 patients were able to recognize and localize sources of light or large, whitish objects. The last three had the chip implanted in the macula, the spot in the retina that normally has the sharpest vision, and after a week were able to see shapes and objects. The final patient was able to correctly identify apples and bananas, read the time from a large clock and recognize individual letters and words within two to three weeks of implantation. Not all blind patients will benefit from this device, including cases where the optic nerve or brain damage is involved, or where the retina is ruined or has insufficient blood flow. Zrenner also cautioned that this work is still in progress, and they are still refining where best to implant the device and learning which patients might benefit most. "It's important not to raise false hope," he stressed. "It will be a while before there is a reliable, marketable device." Source: LiveScience.com