Enviable eyes (Image: Warner Br/Everett/Rex)

Who wouldn’t want to have vision like the Terminator? The possibility is coming into sight thanks to the development of a contact lens that would allow wearers to zoom in on points of interest.

Just over a millimetre thick, the telescopic lens works by having a central unmagnified optical path that is surrounded by a ring of optics that magnify the view 2.8 times. Liquid crystal shutters then block one or the other of these optical paths – allowing the user to switch between regular and magnified vision.

Developed by Eric Tremblay and colleagues at the Swiss Federal Institute of Technology (EPFL) in Lausanne, Switzerland, and at the University of California, San Diego, the lens has been tested on a life-sized model of the human eye. The work has been funded by DARPA, the US defence research agency.


The team built the LCD shutter mechanism into a modified pair of Samsung 3D TV glasses, placed over the eyeball, to simulate that effect. But the groups is confident that the LCD technology can be built into the lens easily – but how it will be switched on and off has yet to be revealed.

Results so far are promising, the team says. “Although the magnified images were clearly visible in our tests, acuity fell short of the design specification,” the researchers report. But they believe they know how to fix the diffraction-related issues with improved refractive optics.

Getting soft

In addition to improving the image, the team also needs to move from the current experimental hard lens – made from hard, clear plastic – to a rigid but gas-permeable material that lets fresh air get to the eyeball, just as in modern soft contact lenses.

The technology could be especially useful for people with age-related macular degeneration. They lose vision in the central area of the retina, and telescopic lenses could replace the clunky “bioptic telescopes” that are currently fitted to their spectacles, to magnify areas of interest.

Elsewhere, however, the ability to magnify a scene without appearing to be wearing any equipment could raise privacy concerns similar to those raised over Google Glass.

There’s a definite need for a zoomable contact lens, says Chris Hull, head of optometry and visual science at City University in London – but it has to be affordable. “Devices that help those with visual impairment are very important, particularly with the ageing population,” he says. “The switchable telescopic contact lens is fascinating technology – but it will need to compete with existing low vision rehabilitation technologies in terms of clinical performance and cost.”

Journal: Optics Express: DOI: 10.1364/OE.21.015980