EmPower’s Pixel Optics glasses change magnification when an electrical current runs through them. They rest in its charging station.

LAS VEGAS — At the International Consumer Electronics Show you find electronics in everything, even the glass of spectacles. A company called Pixel Optics is demonstrating eyeglasses in which an electronic current is passed through liquid crystals to change the prescription on the fly.

Called the Empower line, the glasses are frames with progressive lenses with three focusing zones. Only two focus zones work at a time, eliminating problems some progressive lens wearers experience when the upper and lower prescriptions interfere with the middle. (It’s called “swim”).

When the wearer touches the temple of the Empower glasses frame, the lower portion gets added magnification for close-up reading. When it’s off, the distance and intermediate zones are on. The glasses can also be set to automatically turn on the magnification when the wearer’s head tips down, as when reading, then turn off when the gaze returns to level.

The frames have batteries in the earpieces that are charged on an inductance stand. It takes about eight hours to get a full charge, and the company said to expect a charge to last two to three days. While the batteries can be replaced, the expectation is that most people’s prescriptions will change before the batteries wear out.

The glasses are available in most major markets and in nearly 1,500 shops nationwide, the company said.

But the price may leave you cross-eyed. Expect at least a 20 percent premium over the highest end progressives. That would be around $1,200 to $1,500 a pair.

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