Sadly, there's no two ways about it... ...my eyesight is definitely getting worse! Which, for someone who likes to get out and about, is a right pain. Sports sunglasses are expensive. Sports sunglasses with prescription lenses are VERY expensive. And if, like me, your prescription changes over time, you're faced with scrapping a perfectly decent set of eyewear because the optical bit no longer does the business.

Well, there is an alternative. And, no, I'm not talking about either contact lenses or having laser eye surgery -- sadly neither is appropriate in my case.

Rather that have the whole sunglass lens be the optical element, there are some brands that offer an optical 'insert' system where, like an old-style pince-nez pair of glasses, the optical bit fits behind the sunglass lens. It isn't always an option - some people can't handle the optical bit being that close to the eye - but, given the opportunity to try some new glasses from Adidas, I figured it would be worth a go.

The basic glasses are a single lens design called Supernova which features a dead simple lens interchange system so I can select clear, dark or mid-toned optics - and even swap the arm colours around should I be that much of a fashion victim. The lens is anti-fog treated and, being rimless, doesn't seem to get quite so grungy when it's rainy. They come with a soft bag and a hard case plus an alternative nose-piece for a more customised fit. Mine came in large, which is better for the optical insert, but there is a small version for those with tiny heads.

The Supernova design is simplicity itself and, while it may lack some of the tricked-up 'features' of other brands that I have been known to wear, it delivers exactly what it promises. They are lightweight, they don't move around when you're running or biking, they shade the eye from both light and wind and, while they probably aren't the sort of thing you would wear casually, they certainly won't offent anyone with their styling.

The optical insert plugs into the nose bridge and sits a couple of millimetres behind the main lens. Like any pair of glasses with a small lens, you do notice the insert as being there, but it isn't any more obtrusive than any other small pair of glasses, and it means that I can now actually see the road signs and read the car number plates from a decent distance. And that is worth any amount of peripheral intrusion!

And, there are other benefits as well. The insert can fit into a number of other styles in the Adidas range so, should I wish, I can swap not only lenses but styles as well. Should my prescription change, and it will, I now only have to update one insert to keep the use of a whole set of glasses. And the final benefit is that I didn't need a second mortgage to buy into the system - at £99 for the basic glasses or £164 with the prescription insert it worked out cheaper than just the lenses on my last pair of prescription sports eyewear.

Tri247's verdict: A great solution to the problem faced by people who need prescription eyewear but don't want to lock in to a single solution. As a sports glass they deliver fuss-free protection without resorting to styling gimmicks and you can change lenses and swap optical inserts to other styles, so protecting your investment. Money well spent!