Google stunned the technology industry this year when it revealed its plans to sell Google Glass, eyeglass frames that put a small computer display in a person’s field of vision. But some less well-known companies have been selling wearable displays for years, with the military as a dedicated customer, and one is now launching a rival product with a similar design. The move could be seen as a validation of Google’s idea, but that still doesn’t mean consumers will warm to such gadgets.

Google’s new competitor is Vuzix, based in Rochester, New York. The company’s product has a less catchy name than Google’s—Vuzix Smart Glasses M100—but it contains a microphone, an earpiece, a camera, and motion and GPS sensors, and it’s powerful enough to run a version of the Android mobile operating system. Bluetooth and Wi-Fi connections allow it to be linked to a smartphone. A small display positioned in the wearer’s peripheral vision provides a viewing area equivalent to having a four-inch smartphone about a foot away.

Vuzix already sells wearable—if clunky—displays to consumers looking to immerse themselves in movies, and it provides more expensive products, such as augmented-reality glasses with a camera and display in each lens, to researchers and the Department of Defense. The Smart Glasses, which have a notably slimmer design than those products, should launch next year for under $500.

Paul Travers, the company’s CEO and founder, says the device will start out with relatively few features but will become more impressive as app developers write software for it. “It starts as a phone accessory, like a hands-free headset,” he says. “If your phone rings, it will tell you that your friend Samantha is calling by showing her name and photo.” The glasses will get their data from an app installed on a user’s smartphone. Travers says that approach will make it easier for users to adjust to a mobile device very different from any they’ve used before.

But Travers says he is working with software engineers on more advanced applications for navigation and other purposes. A user’s phone could run the app, and the Vuzix display over the eye would “tell you where to go,” he says.

Vuzix has a longer history in this field, and about 60 patents, but like Google, it will probably face challenges persuading people to actually wear the devices.

“As a user, you need to opt in to the idea of a digital prosthesis,” says Natan Linder, a researcher who designs and builds augmented-reality systems at the MIT Media Lab. “Consider how it would be to have a meeting indoors with a person wearing a Bluetooth earphone or even sunglasses—there’s some social awkwardness.” That’s a barrier the iPhone never faced.

Neither Google’s nor Vuzix’s devices meet a commonly held expectation for such gadgets: that they will display content—like directions—in the center of a person’s vision. (Google’s slick mocked-up promo video was misleading on this point.) With the existing designs, which put the displays to the side, directions would appear as simple notifications that users would see by glancing that way. Although Google has shown off how Glass can stream live video of a person’s viewpoint, it has released no information on how it plans to display information to a wearer.

Vuzix already has technology that can position images right in front of a person’s eye; it demonstrated this at the Consumer Electronics Show in Las Vegas last January, as did the Israeli company Lumus (see our image gallery “The Future Looks Augmented”). It works by using lenses with built-in light guides to steer the output from a tiny display into the middle of an eyeglass lens.

Travers says he has sold versions of that technology to the Pentagon’s early-stage research agency, DARPA, and will launch monocular wearable displays for industrial use in December; the Smart Glasses  will eventually get the technology too. However, costs will have to fall significantly for that to happen. Vuzix’s industrial monocular system is expected to cost $2,500 and up, depending on the features.