Telescopic contact lenses zoom in and out with the wink of an eye
Researchers from the Ecole Polytechnique Federale de Lausanne (EPFL) in Switzerland have developed contact lenses that have tiny telescopic lenses built in to boost vision. Controlled by smart glasses that react in response to the winking of an eye, the device allows the wearer to zoom in on objects by providing magnification up to 2.8 times that of unaided human eyesight.
Originally created under the auspices of Pentagon’s main research arm DARPA, where the lenses may also serve in enhancing future soldier's vision capabilities in the field, this development is an update to a model first released in 2013 and fine-tuned since then. This latest prototype was unveiled by Eric Tremblay from EPFL at the American Association for the Advancement of Science (AAAS) annual meeting.
In its latest form, the contact lenses are also now being promoted as a possible visual aid for those in the civilian arena who suffer from Age-related Macular Degeneration (AMD). AMD is a crippling eye disease that mainly affects sufferers over the age of 55 where the deterioration of their macula (or, more precisely, the macula lutea – an oval-shaped pigmented area near the middle of the retina) leads to a loss of sight in the center of the eye.
"We think these lenses hold a lot of promise for low vision and age‐related macular degeneration," said Tremblay. "It’s very important and hard to strike a balance between function and the social costs of wearing any kind of bulky visual device. There is a strong need for something more integrated, and a contact lens is an attractive direction. At this point this is still research, but we are hopeful it will eventually become a real option for people with AMD."
Just 1.55 mm (0.06 in) thick, the new prototype contact lens contains an exceptionally thin, reflective, two-part magnifying region which is turned on and off in response to the defined movement of the wearer's eyelids. Programmed to be smart enough to differentiate between a longer, deliberate wink and the normal blink of an eye, the glasses that accompany the lenses allow the wearer to wink with the right eye to zoom in, and wink with the left eye to return to standard vision.
"Small mirrors within bounce light around, expanding the perceived size of objects and magnifying the view, so it's like looking through low magnification binoculars," said the researchers.
In detail, the glasses actually achieve magnification control by selecting the polarization of the light that reaches two different apertures contained in the lens. As the lens permits only light polarized in one direction through the standard-vision aperture and only in another way in the magnifying aperture, the user's eye sees only the image where the polarization of the glasses and the polarization of the contact lens aperture are the same.
Unlike ordinary soft-lens contacts, the telescoping lenses are created using larger, rigid scleral lenses – lenses that are placed on the sclera; the white of the eye – from a number of precision-machined plastic components, tiny aluminum mirrors, and thin polarizing films, all held together with biologically safe adhesives. To provide for the constant stream of oxygen required by the eye, the researchers improved the flow of oxygen by incorporating miniscule air channels approximately 0.1 mm (0.003 in) across the structure of the lens.
With further improvements over previous models, which required the user to tilt their head and look through the lens at just the right angle for the effect to be useful, the latest prototype also has the smarts to track eye movement and position the focus accordingly, thereby making them much easier to use and less tiring to wear.
The team working on the prototype lenses included participants from the University of California, San Diego, along with researchers at Paragon Vision Sciences, Innovega, Pacific Sciences and Engineering, and Rockwell Collins.
No announcement has been made regarding any pending commercial or military release of the technology.