1. UV protection

If you are out training a few hours a day, you are exposing your eyes to a lot of UV radiation. Which has a cumulative toll on your eye and surrounding structures. The lens in your eye can develop cataracts faster if you do not protect them with 100% UV blocking sunglasses. All top quality sports sunglasses are 100% UV blocking.

2. Impact resistant

Polycarbonate Lenses are a must. Ask for this lens material by name. If the pair you are considering buying are not polycarbonate think again. This material is super impact resistant, Oakley lenses use a very pure form of this material which can stop very high speed projectiles; the armed forces use them. So this means when you are on the bike hurtling downhill at 70+km/hr and a stone is flicked up by a truck ahead, it will not shatter your lens and send a million tiny pieces into your eye….enough said.

3. Lens optics

The more you pay generally the better quality the optics and materials the frames are made of. Good quality lenses have little or no distortion. Distortion is often the reason why some cheap sunglasses give you headaches. Your brain desires the clearest image it can get and better optics facilitate this.

4. Lens colour

The right lens colour can make all the difference between seeing an obstacle quickly and clearly, before you make that split second decision to dodge or change your direction at high speed. Too dark a lens can reduce the amount of light getting to your eye, this is especially crucial in low light conditions like twilight or dusk. A rose, orange or clear lens colour is best suited to increase your contrast in these conditions. When you are in bright conditions a yellow lens is not suitable, as your eyes will receive too much light and everything you see will be hyperbright. Some sports sunglasses have Transition or Photochromatic technology like Oakley and Rudy Project, which means they change light according to the amount of UV there is. This is a great option as it caters for all light conditions especially on a long ride or run. Sports Specific Eyewear with interchangable lenses of different colours are the next best option.

5. Lens coatings

Mirror coatings can reduce some glare and this can be a real benefit on a bright day. Polarised lenses reduce the most reflected glare and are what boaties and fishermen use to see into the water. These are a must if you squint with even the darkest lens on. Compare them to a normal lens and you will see a significant difference. Hydrophobic lens coatings on the Oakley Radar are as one rider told me “insane”, the water literally beads off them unlike any other sunglass lens in the rain.

6. The fit

They must fit well, so they don’t fog up when you are hot. Make sure they are not too tight and that when you are in the aero position the lens still blocks out the wind and lets you see through it. The Adidas Supernova won a cycling sports award for this frame, it sits higher on the bridge and triathlete Bevan Docherty wears this model.