Photo: Dan Hixson / University of Utah College of Engineering

 

 

Ernst Freiherr von Feuchtersleben, a doctor and philosopher from Austria, knew back at the start of the nineteenth century: “If your vision is clear, the world is, too.” The same holds true now, two hundred years later: If the world is blurry, something’s wrong.

And blurriness is a growing problem. Nearsightedness and farsightedness are becoming more common in the industrialized world, particularly with age, and with both conditions occurring simultaneously. When the book right in front of your eyes is just as out of focus as the street sign several meters away, things get tricky—and troublesome. Progressive lenses or an eye operation aren’t for everyone, so often the only solution is to use two sets of glasses.

Researchers at the University of Utah have now developed eyeglasses that can take on the function of the eye’s lens and focus themselves. The lenses for these glasses are made of glycerin, a viscous material that is enclosed by a rubbery membrane. In each lens, the backside of the rubber skin is connected to a mechanism that can push and pull the membrane. This changes the curvature of the fluid lens as well as the focal length.

In the bridge of the glasses, above the nose, is an infrared telemeter, which measures the distance from the glasses to an object. When the wearer of said glasses is focusing on an object, the telemeter detects the exact distance and transmits this information to the mechanism, determining how the lens should be adjusted. The change and focusing are supposed to take just 14 milliseconds.

Whether or not we can actually see more clearly with just one set of glasses should become clearer within the next three years. It will take about that long for a lighter, more stylish version to replace the present clunky prototype and be introduced to the market. Ernst Freiherr von Feuchtersleben would probably have been clearly impressed.


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