New electronic circuit for smart contact lenses

Scientists have developed an ultra-flexible electronic circuit that is tiny and thin enough to fit on the surface of a contact lens.

Researchers said an electronically-enabled lens could have medical uses, for example, it could be useful in monitoring the intraocular pressure of people with glaucoma.

"I believe this technology can have important impacts in medicine and health monitoring," said lead author Giovanni Salvatore, a researcher at the Swiss Federal Institute of Technology in Zurich (ETHZ).

"It could be used for very wearable and minimally invasive devices, for ultralight solar cells, and most importantly, for very conformable and implantable devices which can serve to monitor biometric parameters in the human body," Salvatore said.

Creating the circuits - which are printed on a one-micrometre thick layer of a substance called parylene is a multi-step process.

To begin, the scientists deposit the parylene on vinyl polymer that provides support, then print the circuitry on top of the parylene.

Afterward, the entire chip is placed in water, which dissolves the underlying polymer, leaving the ultra thin circuitry intact. The result is something that's about one-sixtieth as thick as a human hair, Smithsonian magazine reported.

The circuit is extremely flexible, bending and crinkling to fit around, for instance, a hair, plant leaf or finger while still functioning properly.

Since it's extremely lightweight, it could be feasibly used in a range of long-term medical applications.