Like Google Glass, but invisible.

Wired reveals a pair of smart glasses that don’t look any different than any other pair of prescription frames – wearable computers just the way Zeiss (and maybe the rest of us) wanted them:

There’s plenty to say about wearing Zeiss’s smart glasses, but the most important point—at this stage, maybe the only point—to make is that they feel like glasses. Not clunky glasses, not heavy glasses, not glasses with Coke-bottle lenses or a dorky attachment that telegraphs just how many years in the future you live. They feel like the glasses you wear every day.

That’s hard to accomplish. Very hard. Zeiss did it by integrating a Fresnel structure into a standard lens, and mounting a very small display at the edge of the lens. There are complicated optics at play here, but essentially the light from the display is reflected into the lens and hits the Fresnel structure, which reflects that light into your eye. A smartphone feeds the system images, and a smartwatch controlled navigation in my demo.

“Glasses now are sold by design. It’s an illusion right now to think that somebody goes to an optician and really wants a perfect lens. He just wants a perfect frame that looks good afterward,” says Dr. Kai Jens Ströder, who leads Zeiss Smart Optics, the wholly owned start-up within Zeiss dedicated to making this smart glass dream a reality. “You have to bring the lens to the frame, and adapt the lens that it fits in stylish frames, and not the other way around.”

If nothing else, Zeiss has accomplished this.

That it works at all feels revelatory. The only awkward attachment was a hookup to a battery pack, something that won’t be necessary if and when an actual production version launches. At least, not all the time.

The display’s shortcomings in bright light should be helped, if not entirely remedied, by much brighter OLED displays coming later this year.