As many an iPhone user has found to their dismay, glass screens crack all too easily. One slip onto a hard floor and your precious smartphone's screen could be smashed.

Plastic screen protectors are almost literally two-a-penny (just look on Ebay) and most are absolute rubbish. They're hard to apply and, more often than not, look like an oil slick.

Tech21's Impact Shield is an exception, as it's optically clear, but it's still tricky to apply compared with Moshi's iVisor XT (which is easy, but looks like an oil slick in the wrong light).

QDOS is the first company we know of to launch a glass screen protector: the OptiGuard-TG. It's available for only the iPhone 5 at present, but it makes a lot of sense. Effectively, it's a disposable screen that's considerably cheaper than replacing your iPhone's screen, yet it's just as tough.

QDOS OptiGuard-TG

The OptiGuard-TG is tempered glass which has an oleophobic coating, just like the iPhone, so fingerprints and dust are easy to clean off with the included microfibre cloth. QDOS says the protector is three times tougher than plastic, and that's not difficult to believe: the glass is 0.4mm thick.

It's barely noticeable once applied and doesn't have sharp edges. You get two rubber stickers (one black, one white) to cover your Home button to bring it flush with the top of the screen protector, but they look a little odd and aren't really necessary.

Applying the OptiGuard-TG is no different from a traditional plastic screen protector. First you scrupulously clean your screen, using the included sticker and cloth to remove dust and grime. Then, peel off the backing, align the protector and press it into place.

As long as you've successfully eliminated all dust, you'll have a blemish-free finish (there are no bubbles of course, and if there are any tiny pockets of air, they'll disappear within a day or so).

There's just one slot cut out for the speaker - the front camera shoots through the glass with no problems at all.

QDOS OptiGuard-TG

OptiGuard-TG review: verdict

It may be expensive for what is essentially a small piece of thin glass, but the same criticism can be levelled at other, plastic, screen protectors. Given that even a 16GB iPhone 5 costs £529, an extra £25 to ensure its screen remains pristine is well worth it.