The rest of the rivals: Round 1
Aside from the big boys' offering, there are various similar devices that are either available to purchase now or for pre-order.
The American company has been producing head-mounted tech for quite a while now, with a range of digital eyewear already on the market that promises to deliver immersive movie and gaming experiences. Its M100 Smart Glasses were first shown off at CES 2013; they're now available to pre-order for US$1000.
Rather than being the smartphone companion that most other manufactures have been gunning for, Vuzix has managed to cram the guts of a mid-range Android smartphone into the unit; it features a 1GHz processor with 1GB of RAM, running Android Ice Cream Sandwich. It all makes for an independent experience that the firm calls the world's first 'hands free smartphone.'
These sporty specs, Recon CEO Dan Eisenhart says, are "nothing like Google Glass." Aimed at athletes, the Recon Jet is, like the Vuzix, an independent device that doesn't rely on being tethered to a smartphone. Onboard, you get a 1GHz dual-core processor, a gyroscope, compass and accelerometer, pressure sensor, thermometer, Bluetooth 4.0, 802.11n Wi-Fi, an HD camera, GPS, Ant+ (for hooking up fitness peripherals) and an open-source operating system based on Android.
They're already available to order at US$600 (around £375) a pop.
Like Recon Jet, GlassUp is based around a full pair of specs – but they're rather less sporty, having more in common with the protective glasses that your science teacher dished out before performing a chemistry experiment.
Rather than using a peripheral vision-hogging display, GlassUp uses 'real' heads-up technology to beam notifications on to the right-hand lens, which the makers claim makes for a less obtrusive experience. Although they have a cut-down version of Android on board, they rely on a smartphone app for connectivity; this means they can claim better usability and a less cumbersome interface than some, thanks to the Glass-esque side-mounted touchpad.
Available to pre-order in a range models, including a variant with and without glasses, and with optional prescription lenses, GlassUp goes for between US$300 (£190) and US$500 (£315).
The rest of the rivals: Round 2
Little is known about the Nissan 3E smart eyewear, aside from a teaser video revealing that it's a rather chunky affair. It wraps around the back of the head rather than the front, displaying images on an angled glass screen worn over your left eye.
Since it's designed for drivers, Nissan's recently revealed Nismo smartwatch concept offers some clues as to how the 3E will work – the Nismo tracks biometric data and displays social media and traffic alerts, and it's likely that the two devices will work together.
Set apart from the other smartglasses we've featured are these traditional-looking glasses from Epiphany Eyewear. Rather than trying to cram an entire computer or notification smarts into a wearable frame, they've instead focused on the ability to capture the visual and auditory world around you using an inbuilt HD video camera. It's activated by a single tactile switch on the side, with the only other truly smart ability coming in the form of live streaming though a phone using YouGen.TV (this lets your Facebook friends in on the action).
To ensure they're still a viable wearable, there's also a button that engages polarisation, turning them from trendy specs into suitable sunnies. So they're not all style over substance.
They're available to pre-order in 8GB, 16GB or 32GB (US$300, US$400 and US$500 respectively – that's around £190, £250 and £315) varieties and there’s a Micro USB plug for recharging and data transfer.
Better known for producing HUD displays for the US Air Force, Lumus is dipping its toe into the civilian wearable tech market with the DK-40. The hipsterish smart glasses are being released to developers in early 2014 following a debut appearance at CES. They've already one-upped Google Glass with their display; rather than projecting data onto glass, the DK-40 features a transparent 640x480 display that fills the entire right lens. Other specs include a 5MP camera and motion sensor, plus an OS based on Android; you'll have to wait until CES for more details, though with battery life a scant 1-2 hours, the DK40 clearly has some way to go yet.