Using simple glycerine contained between two membranes, University of Utah researchers developed glasses that automatically adjust focus.
With the help of an infrared distance-measuring device, some electronic circuits, and a mechanical actuator that adjusts the lens' rear membrane, the process takes only 14 milliseconds.
Instead of changing glasses for driving or reading, or adjusting your eyes as you look from a near to a distant object and back, the glasses do the adjustment for you.
As lead researcher Carlos Mastrangelo explained, "You put these on, and it's always clear."
The prototype is still bulky, with thick frames and handles containing the electronics and the battery, but researchers say they are working on a lighter version, much closer to ordinary glasses.
Even better, they say when the new glasses reach mass production, the owners will be able to wirelessly download their prescription whenever it changes.
Researchers say the autofocusing glasses could be on the market in about three years.