Biometrics. Now that's a word we'll be hearing more of in the world of tech. Having seen plenty of fingerprint scanners on phones in recent years, the ZTE Grand S3 goes one step further: incorporating EyeVerify retina scanning technology, which can be used to unlock the phone with just your eyes.

Well, almost. A swipe down on the screen with a finger is required first, adding one additional step, which in turn opens a window and activates the front camera. Look into this window and the tech jumps into play, verifying the associated biometric data and unlocking the phone in a matter of seconds.

If, of course, it's your phone and eyeballs eyeing it up. Try though we might, the phone we handled at Mobile World Congress - registered to Waiman Lam, ZTE's senior director of technology and partnership - refused our entry attempts.

It's an effective tech, but feels like a first step in an ongoing development rather than a fully fledged solution. Right now it's not quite fast enough to warrant using it instead of a PIN code, for example, while low-light conditions require the glow of the front screen to illuminate the eyes. 

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The follow-up to 2013's Grand S II, the Grand S3 is a different beast of a phone: the 5.5-inch screen may be the same size as its predecessor, but the 9.8mm thickness of the device makes it fairly chunky. And in a world where phones are slimming down - some almost some 50 per cent slimmer - it's a hefty phablet.

But the reason for that bulk is the capacious 3100mAh battery tucked away within. It's a removable battery, accessed by removing the plastic rear, which also exposes the dual SIM and microSD sockets. Whether having a plastic phone is off the cards will be down to personal preference - but we think a slimmer unibody with a higher-end finish would score the Grand S3 more Brownie points.

The rest of the specification isn't to be sniffed at, however, with a 2.5Ghz Qualcomm Snapdragon 801 processor ticking away beneath, 3GB RAM, 16-megapixel rear camera, and a Full HD (1920 x 1080) resolution screen.

That's plenty of power, with the Android interface operating smoothly in our hands-on use. There is a ZTE re-skin, called Mifavor 3.0, but the user interface doesn't heavily adjust the Android operation. The main difference is the ability to select colour schemes and live backgrounds with a simple swipe up from the base of the device, adding a lick of colour and brightness to proceedings.

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Sounds like one to keep an eye on? The ZTE Grand S3 is available in China from March, priced 3,000 Renminbi, with other territory availability yet to be verified. Whether that means no sale in the UK isn't yet clear, but on a conversion basis that's a £311 equivalent (we would anticipate £399 retail).

As the smartphone to add weight to biometrics in tech there's a lot to be said for the ZTE Grand S3. Certainly one to keep an eye on... or maybe both eyes.