Newscientist has the story on this developing technology that could work to, among other things, help detect fatigue in pilots by monitoring chemical biomarkers present in the wearer.
Most of today’s 3D printers work with scraps of plastic or metal and turn them into simple objects. But Michael McAlpine at Princeton University and his colleagues have developed a 3D printer that can make a five-layered contact lens, one which emits light into the wearer’s eyes.
The lens is a transparent polymer with several components embedded inside: nanoscale quantum dot light-emitting diodes, wiring made from silver nanoparticles, and organic polymers that could act as parts of electrical circuits.
The trickiest part, McAlpine says, was working out which chemical solvents would deposit each layer best, leaving them dry enough for the next layer to adhere.
Another challenge was the fact that everyone has uniquely shaped eyeballs. The team scanned the contact lens constantly with two cameras to ensure the final shape matched the user’s prescription.
The work was funded by the US Air Force, which hopes to use such lenses to display in-flight data. Replacing the LEDs with light sensors could also reveal the state of the wearer’s retina and possibly monitor pilot health without invasive implants.
They could also be replaced with sensors that detect chemical biomarkers of fatigue in eye fluids, McAlpine suggests. “Planes have sensors for the state of everything, except the most important thing: the pilot’s exhaustion level,” he says.