Visionary Tech: Eye Implant Restores Some Sight in Blind

new eye implant gives blind people sight — The implant is placed under the retina, the inner lining of the eye. The device essentially replaces degenerated light-sensitive rod and cone cells of patients suffering from diseases such as retinitis pigmentosa, a group of inherited diseases that afflict 1 in 4,000 people across the world.

(Image credit: © OPTOS)

Using light-sensitive microchips implanted in the inner surface of the eye, scientists are continuing to restore some vision to blind patients — for instance, helping them recognize facial expressions such as smiles.

The visual sharpness of the new devices surpasses the highest resolution of any other visual implant so far, researchers added.

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The implant, named the Alpha-IMS, is only about 3 millimeters long by 3 millimeters wide, and less than 100 microns thick, making it thinner than the average diameter of a human hair. Despite its tiny size, the microchip is loaded with 1,500 light detectors, which transmit electrical impulses through a patient's nerves to generate a colorless 1,500-pixel image. In contrast, other visual implants provide images with significantly less than 100 pixels. [See Images of the Eye Implant]

In the first study with the implant, detailed in 2010, the device could help patients read the hands of a clock, discern seven shades of gray, find tableware, identify apples and bananas, and combine the letters of the alphabet to form words. However, most of the 11 patients given the implant did not achieve these results, partly because researchers were still refining where best to implant the device and learning which patients might benefit most.

In the latest human clinical trial with these chips, nine German patients were tested in the laboratory as well as outdoors and at home during a three-to-nine-month period. The device restored functional vision for most of the patients — for instance, eight could perceive light, seven could tell where light was coming from and five could detect motion. The success of this latest clinical trial is largely due to the researchers now knowing to place the implant under the fovea, a spot near the center of the retina that is responsible for the center of the field of vision.

Moreover, visual sharpness for two of the patients surpassed acuity seen in the first clinical trial. Three were able to read letters spontaneously. In addition, in and outside the laboratory, five patients reported the ability to recognize facial characteristics such as the presence or absence of eyeglasses, as well as distinguish objects such as telephones, read signs and find doorknobs, see where plates and cutlery were on tables and tell red wine from white wine. Patients described blurry, flickering images of the world in gray tones, reminiscent of unfocused images from an older black-and-white television set. [Eye Tricks: Gallery of Visual Illusions]

The researchers would now like to improve the durability of the implant against the corrosion it can experience. "It's a challenge working with something that thin, to protect it against water and ions in the eye," Zrenner said. "We're in a situation like that of the first airplanes, which were made of wood and paper, more or less. We now have to work on materials science a lot, since the body is a hostile place for electronics."

Charles Q. Choi is a contributing writer for Live Science and Space.com. He covers all things human origins and astronomy as well as physics, animals and general science topics. Charles has a Master of Arts degree from the University of Missouri-Columbia, School of Journalism and a Bachelor of Arts degree from the University of South Florida. Charles has visited every continent on Earth, drinking rancid yak butter tea in Lhasa, snorkeling with sea lions in the Galapagos and even climbing an iceberg in Antarctica.