And video-game companies could use the new lenses to immerse players in a virtual world without restricting their range of motion.

A team led by Babak Parviz, assistant professor of electrical engineering at the University of Washington, used manufacturing techniques at the microscopic level to combine a flexible, biologically safe contact lens with an imprinted electronic circuit and lights. Such an electronic lens overlays a head-up display on the user’s visual field.

“This is a very small step, but I think it’s extremely promising,” says Parviz. The prototype device contains an electric circuit as well as red LEDs for a display, which is not yet functional. Installing or removing the bionic lenses should be as easy as popping a contact lens in or out, says Parviz.

Building the lenses was a challenge because materials that are safe for use in the body, such as the flexible organic materials in contact lenses, are delicate. Manufacturing electrical circuits, however, involves inorganic materials, extreme temperatures, and toxic chemicals.

Researchers built the circuits from layers of metal only a few nanometers thick. They constructed LEDs one-third of a millimeter across and placed the electrical components onto a sheet of flexible plastic. The shape of each tiny component dictates which piece it attaches to, a microfabrication technique known as self-assembly. Capillary forces — the same forces that drive water upward in plants — pull the pieces together.

The prototype lens does not correct the wearer’s vision, but the technique could be used on corrective lenses, Parviz says. And all the gadgetry won’t obstruct a person’s view.

“There is a large area outside the transparent part of the eye for placing instrumentation,” Parviz says. Future improvements could add wireless communication. Researchers hope to power the electronics with radio-frequency power and solar cells on the lens.

A full-fledged display won’t be available for a while, but a basic version could be operational soon.

Electronic contact lens has LEDs in the center and support circuitry around the edges, out of the wearer’s field of vision.

In lab tests, rabbits safely wore contact lenses with metal connectors for electronic circuits for up to 20 min.