No matter how good your eyesight, there's a decent chance that it'll start to fade at a certain point in your life. Presbyopia is a common form of age-induced far-sightedness, where the lenses in the eyes become stiff and have trouble focusing on close-up objects. Now a Stanford team has developed a pair of high-tech specs called autofocals, which use fluid-filled lenses, depth-sensing cameras and eye-tracking technology to make sure whatever a wearer is looking at stays sharp.

The most basic solution to presbyopia is a pair of reading glasses, but they need to be taken off to see at a distance. Progressive lenses, which have multiple regions for viewing at different distances, can be worn all the time, but have notoriously little focus in the periphery.

The Stanford autofocals are designed to fix those problems. The lenses in the prototype are filled with fluid that reacts to an electric current, becoming thinner and thicker to change the depth of the focus as needed. Working alongside those lenses is an eye-tracking system that watches where the wearer is looking, and a depth-sensing camera that calculates how far away a given object is, and adjusts the focus accordingly.

"More than a billion people have presbyopia and we've created a pair of autofocal lenses that might one day correct their vision far more effectively than traditional glasses," says Gordon Wetzstein, co-author of the study.

The team tested these autofocals on 56 people with presbyopia. The test subjects reported that the new glasses made it easier and faster to read and do other tasks, compared to regular old progressive lenses.

The researchers acknowledge that they aren't the ones to invent either the lenses nor the eye-tracking tech, but they seem to be the first to combine the two into one system to tackle sight problems. Other similar devices have used the special lenses with motion sensors so they change to the right prescription when the wearer looks up or down, while others have wheels to allow the focus to be adjusted manually.

The closest thing to the Stanford autofocals is a device from the University of Utah, which uses infrared pulses to measure the distance to objects and adjusts the focus of the lenses accordingly. But that didn't have eye-tracking.

The next steps for the team are to downsize the technology – currently, they're bulky like a virtual reality headset, which was a common complaint from the study participants. Making them lighter, more energy efficient and more stylish could help them become an everyday item.

The research was published in the journal Science Advances.

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