LAS VEGAS — Smartwatches were the wearable darling of CES 2015, but they're easy to create. Start with fitness tracking, throw in some notifications, maybe even park your car with them, and you've got the latest buzzworthy product.  Smart glasses are much harder. Bringing information directly to a person's eye has the potential to reduce the friction between humans and technology more than any other wearable, but they need to walk a difficult tightrope between convenience and intrusion. And to have any hope with consumers, smart glasses can't look like something only the characters from The Big Bang Theory would wear.  Put simply, smart glasses are hard to build and create user experiences around.  Informed by two years of experience with Google Glass, at least the category is now clearer, and most models fall into one of two buckets: First, there are those that deliver Glass-like experiences where a screen floats above one eye, providing notifications and other glanceable information to the wearer.  Then there are models that use dual screens over each eye to create a virtual screen overlaying the real world. The information onscreen can either provide information about what's in the field of view, or immerse the user within something else entirely. This is augmented reality.  Both types of smart glasses were at CES. But can either one capture a mainstream audience?  "Definitely," according to Epson president Minora Usui, whose company makes the Moverio smart glasses. "The reason we wear [normal] glasses is to see things we can't see with the naked eye. In the same way, the purpose of smart glasses is to see information you couldn't otherwise see. The demand for smart glasses will increase dramatically over the next few years."  Sony showed the clearest — and most promising — Google Glass competitor in its SmartEyeglass Attach, a small display that you can clip onto a regular pair of sunglasses.  The Sony SmartEyeGlass Attach, still a concept at this point, is a tiny connected display that attaches to any pair of glasses.  I tried out the Attach, and although I was only able to use it in demo mode, I came away impressed. Because the screen is a tiny OLED display and not a projected image like that of Glass, the information appears completely clear, and it doesn't obstruct your vision since it's in your blind spot, anyway: You might glance at it to see, say, the speed of your golf swing, but it disappears when you look away.  The Attach is a great idea, and when it was clipped onto a pair of minimalist spectacles, I'd daresay Sony's gadget even looked pretty good — except for that Borg implant growing out of the side of my head.  We've all seen how such a design has worked for Glass, so Sony's product has little chance to go mainstream. But as a visual aide for specific situations? It's as good as Glass — if not better.  Then there are the augmented-reality glasses, such as ODG's digital specs. As I wore them, watching various virtual people throw fruit at me in a 3D demo reel, Nima Shams, the company's vice-president of headworn devices, proudly pointed out that the glasses run full Android and can create a tablet experience that floats in front of your face.  Um, great? In all seriousness, being able to operate a "tablet" hands-free has clear advantages, but using a pair of augmented-reality glasses as a tablet or smartphone replacement often feels like a solution in search of a problem. Is anyone really clamoring for this?  ODG's smart glasses offer an impressive augmented-reality experience in a relatively compact design.  In addition, that's only one use case for AR. It isn't really meant for watching YouTube on a virtual screen — it's about calling up information and imagery that's relevant to what you're looking at. Feeling hungry while walking near a Shake Shack? Smart glasses should be able to direct you with arrows, show you a menu and let you call in your order.  "Because of the conversations that Google Glass and Oculus [VR] started, you have all these talented app developers that want to develop for this new media, this platform," Shams said. "It's familiar in that it's Android, it's apps, but it's different in that it's see-through. It sparks the imagination."  The preproduction model that ODG showed me seemed more than capable of doing all that, provided the app support arrives, though the hardware is still a little clunky. The projectors and optics add some heft, and although it's less weird-looking than Google Glass, it's hard to imagine anyone wearing them all — or even most — of the time.  To capture a mainstream audience, smart glasses need to be compact and stylish enough that they feel just like a regular pair of glasses. The technology needs to disappear. The closest thing I saw at CES that fits that bill is Vuzix's waveguide technology (similar to fiber optics), which creates images on lenses — no "prisms" or weird outgrowths from your temple. That way, the frames look normal, and the lenses stay transparent.  Vuzix's consumer model hadn't been perfected in time for the show, but I did see a working pair of prototype lenses, as well as the frames in which the company intends to build them. They looked just like something Bono would wear if Vuzix can put them together, which is likely, now that Intel has invested $25 million in the company.  "What Google was trying to do, Vuzix is going to do," company CEO Paul Travers said. "Once people start using these guys, they won't go back to their phones."  Vuzix intends to build its latest waveguide tech (left), which can overlay a high-res screen on transparent lenses into a pair of compact frames (right).  While we wait for the promises of CES to become real (if ever), Google Glass will have an opening to recapture the spotlight. Soon, we'll probably see the first Glass designs from the deal that the company made with Ray-Ban maker Luxottica. Unless those get rid of that silly computer hanging off the side, however, they won't likely change the conversation.  TL;DR: For all the promise on display at CES, consumer smart glasses aren't really here, yet. But there's reason to believe the wait won't be much longer. In the meantime, we'll have to settle for getting notifications on our wrists.  Have something to add to this story? Share it in the comments.
Will smart glasses, such as Google Glass, go mainstream any time soon? CES 2015 offered a few promising candidates.