Electronic contact lens displays pixels on the eyes

Paul Marks, senior technology correspondent

Rabbit's-eye.jpg(Image: Institute of Physics)

The future of augmented-reality technology is here - as long as you're a rabbit. Bioengineers have placed the first contact lenses containing electronic displays into the eyes of rabbits as a first step on the way to proving they are safe for humans. The bunnies suffered no ill effects, the researchers say.   

The first version may only have one pixel, but higher resolution lens displays - like those seen in Terminator - could one day be used as satnav enhancers showing you directional arrows for example, or flash up texts and emails - perhaps even video. In the shorter term, the breakthrough also means people suffering from conditions like diabetes and glaucoma may find they have a novel way to monitor their conditions.

In February, New Scientist revealed the litany of research projects underway in the field of contact lens enhancement. While one company has fielded a contact lens technology using a surface-mounted strain gauge to assess glaucoma risk, none have built in a display, or the lenses needed for focused projection onto the retina - and then tested it in vivo. They have now.

"We have demonstrated the operation of a contact lens display powered by a remote radiofrequency transmitter in free space and on a live rabbit," says a US and Finnish team led by Babak Praviz of the University of Washington in Seattle.

"This verifies that antennas, radio chips, control circuitry, and micrometre-scale light sources can be integrated into a contact lens and operated on live eyes."

terminator1008879b.jpg I'll be back: Could electronic contact lenses give humans Terminator-like vision in the future? (Image: Solent News & Photo Agency/Rex Features)

The test lens was powered remotely using a 5-millimetre-long antenna printed on the lens to receive gigahertz-range radio-frequency energy from a transmitter placed ten centimetres from the rabbit's eye. To focus the light on the rabbit's retina, the contact lens itself was fabricated as a Fresnel lens - in which a series of concentric annular sections is used to generate the ultrashort focal length needed.

They found their lens LED glowed brightly up to a metre away from the radio source in free space, but needed to be 2 centimetres away when the lens was placed in a rabbit's eye and the wireless reception was affected by body fluids. All the 40-minute-long tests on live rabbits were performed under general anaesthetic and showed that the display worked well - and fluroescence tests showed no damage or abrasions to the rabbit's eyes after the lenses were removed.

While making a higher resolution display is next on their agenda, there are uses for this small one, say the researchers: "A display with a single controllable pixel could be used in gaming, training, or giving warnings to the hearing impaired."

"This is clearly way off in the future. But we're aware of the research that is ongoing in this field and we're watching the technology's potential for biosensing and drug delivery applications in particular," says a spokesperson for the British Contact Lens Association in London.

Journal Reference: Journal of Micromechanics and Microengineering