A team at the University of Utah has created “smart glasses” with liquid-based lenses that can automatically adjust the focus on what a person is seeing, whether it is far away or close up.

Research on the adaptive lenses was published in Optics Express.

Early prototype of the device. Dan Hixson/Univ. of Utah College of Engineering Early prototype of the device. Dan Hixson/Univ. of Utah College of Engineering The human eye has a lens inside that adjusts the focal depth depending on what you look at. But as people age, the lens loses its ability to change focus, which is why many people require reading glasses or bifocals.

The research team created eyeglass lenses made of glycerin, a thick colorless liquid enclosed by flexible rubber-like membranes in the front and back. The rear membrane in each lens is connected to a series of three mechanical actuators that push the membrane back and forth like a transparent piston, changing the curvature of the liquid lens and therefore the focal length between the lens and the eye.

According to researchers, the focal length of the glasses depends on the shape of the lens, so to change the optical power the membrane shape itself is changed.

The lenses are placed in special eyeglass frames, also invented by members of the research group, with electronics and a battery to control and power the actuators. In the bridge of the glasses is a distance meter that measures the distance from the glasses to an object via pulses of infrared light.

When the wearer looks at an object, the meter instantly measures the distance and tells the actuators how to curve the lenses. If the user then sees another object that’s closer, the distance meter readjusts and tells the actuators to reshape the lens for farsightedness. The lenses can change focus from one object to another in 14 milliseconds, researchers say. A rechargeable battery in the frames could last more than 24 hours per charge.

Before putting them on for the first time, users must input their eyeglasses prescription into an accompanying smartphone app, which then calibrates the lenses via a Bluetooth connection.

Currently, the team has constructed a working prototype that they put on display in January at the Consumer Electronics Show in Las Vegas. A startup company, Sharpeyes LLC, has been created to commercialize the glasses.

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