Bionic contact lenses could detect diseases such as multiple sclerosis, track diabetes though glucose monitoring and give internet access. For example, Babak Parviz and colleagues at the University of Washington have demonstrated a contact lens with electronic circuit and red LEDs giving text that is only one third of a millimeter across. They envisage later versions of such devices acting as the display of your mobile phone and providing a more realistic computer game experience. The device will be in the form of a conventional contact lens but with added bionics technology.
"Looking through a completed lens, you would see what the display is generating superimposed on the world outside," said Parviz. Putting sensors and displays into contact lenses is difficult as the lenses are small, lightweight and delicate but this can be addressed by making the components on the nanoscale or microscale. "The thickness of the lens is about 100 µm and at the moment the components are around 4 µm thick" says Parviz. "It is a very similar weight to normal contact lenses and it could be integrated with the usual vision correction of contact lenses."
To complete the lens, the researchers sprinkled a greyish powder of electrical components onto a sheet of flexible plastic. The shape of each tiny component dictates which piece it can attach to, a microfabrication technique known as self-assembly. Capillary forces pull the pieces into position. The prototype contact lens does not correct the wearer's vision, but the technique could be used on a corrective lens, Parviz said. And all the gadgetry won't obstruct a person's view as the eye relies on only a small amount of light entering the pupil at a time so wearers will still be able to see through the lens while the circuitry is built around the blind spots.
The researchers have demonstrated that they could power the lens using radio signals and currently the prototype's antenna can collect radio frequency waves and turn them into energy. These signals would eliminate the need for any embedded power supply, such as batteries that could contain chemicals harmful to the eye. The built-in antenna will also use wireless technology, similar to that used in the home, to beam information to the lens allowing wearers to surf the internet. To communicate with a computer to send sensor data or receive internet pages, for example, requires an antenna and radio chip. The antenna size is related to the frequency of the radio waves.
Parviz 's displays and sensors are likely to be powered by a combination of radio frequency power and solar cells placed on the lens. A full-fledged display won't be available for a while, but a version that has a basic display with just a few pixels could be operational "fairly quickly," according to Parviz.
Credit: University of Washington
Top Image source: Sandia National Labs
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