Scientists are developing smart contact lenses embedded with tiny mirrors that can magnify your vision by almost three times.
The 1.55mm-thick lenses incorporate a thin reflective telescope made of mirrors and filters; when light enters the eye it bounces off the series of mirrors and increases the perceived view of an object or person.
It is hoped that the lens will improve the sight of people with age-related macular degeneration (AMD), the third leading cause of blindness globally.
AMD causes the loss of central vision due to gradual damage to the eye's retina and there are few options for cure or treatment. "AMD is the biggest problem where magnification is a proven visual aid," says Eric Tremblay, research scientist at EPFL in Switzerland.
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Tremblay led the optical design of the lens, which is based on a surgically implantable telescopecurrently used by some patients with AMD, but which is more invasive than a lens.
"With a contact lens, it's easy to try it," says Tremblay.
A key innovation with the lenses is the added ability to switch between magnified and regular vision through a complementary pair of glasses.
The battery-powered glasses use LCD technology to watch the movement of the eye and a simple wink can alter their polarization and determine whether light entering is magnified or not, "having the ability to switch on demand is attractive," says Tremblay.
The ability to selectively magnify your vision makes the design of the glass-lens combination more suitable for daily life.
"When magnified you lose a lot of your field of view, your peripheral vision," says Tremblay.
A strategic wink will enable users to keep an eye on their periphery, such as cars approaching them as they cross a street, whilst also being able to zoom in and recognize the faces of those around them.
The team developed their technology on scleral lenses, which have an increased thickness and diameter, making them commonly used for more special purpose eye care. "[They provide] a lot more area to work with," says Tremblay.
The challenge these lenses bring with them, however, is comfort, as they impede the amount of oxygen reaching the eye.
The most recent prototype, unveiled by the team in February, overcame this challenge by introducing air channels to aid the flow of oxygen to the eye, but the team hopes to improve this further still by instead developing a contact lens solution saturated with oxygen which can be stored and slowly released into the eye. "[We will] build reservoirs into the back of the lens," says Tremblay.
The lenses have only been tried on a handful of humans to test for comfort, with the majority of research to date performed in the lab using a model chemical eye, but more human trials are on the cards with the eventual goal of daily wearable contacts to aid the visually impaired.
"We want it to move in the direction of a real world vision aid," says Tremblay.