Spring's here. The sun's climbing back over the top of the day, the 6am starts are getting lighter, and half the country is about to dig their sunnies out of the glovebox. Good time to sort out the one spec nearly everyone gets wrong.
Polarisation. It's printed on every sunglasses product page in Australia, usually next to the price, usually with no explanation of what it does. Most people read it as "better." It isn't better. It's different — and there are a handful of situations, including ones you'll hit on a normal Saturday ride, where a polarised lens is quietly working against you.
What polarisation actually does
Light bouncing off a flat surface — wet bitumen, a car bonnet, the ocean, a windscreen — comes back mostly aligned in one direction, horizontally. That's glare. Not brightness — a specific, organised kind of light that swamps everything behind it.
A polarised lens has a filter running the other way through it. Horizontally aligned light gets blocked. Everything else comes through more or less untouched.
That's the whole trick. A filter for one type of light, not a general dimmer. Which is why it's brilliant in some conditions and useless in others.
Polarised does not mean UV protection
This is the one worth writing on your hand.
Whether a lens is polarised tells you nothing about whether it blocks UV. They're two separate features, built into the lens for two separate reasons, and they have no relationship to each other.
You can buy a polarised lens with rubbish UV filtering. You can buy a completely clear lens with full UV400. Plenty of cheap sunglasses lean on "polarised" precisely because it sounds technical and costs less to deliver than a proper UV filter.
The two do different jobs. Glare reduction helps you see, right now, today. UV protection is the long game. ARPANSA is direct about it: continual UV exposure damages the eyes, with cataracts as the long-term bill and photokeratitis — sunburnt cornea, and it feels exactly as good as it sounds — as the short-term one.
So check for UV400, and check the lens category number. If a pair advertises "polarised" and nothing else, they've told you the less important half.
The category number, quickly
Australian sunglasses are graded 0 to 4 under AS/NZS 1067, and the number is on the swing tag by law.
- 0 and 1 — fashion spectacles. Barely tinted. Not sunglasses in any useful sense.
- 2 — medium glare reduction. Fine for overcast days and early starts.
- 3 — high glare reduction. The workhorse for Australian daylight, and what almost every serious sports lens is.
- 4 — very high. Built for snow, deserts and open water. Not for driving — they're required to carry that warning on the label. If you're riding home in traffic, this matters.
Category and polarisation are independent — a Cat 3 lens can be polarised or not. Ours are both, at 17% VLT, which for Australian daylight is the combination that makes sense most days of the year. There's a longer breakdown of what the categories actually mean if you want the detail.
Where polarisation earns its keep
If you run or ride in Australia, it wins most of the time. Specifically:
Wet roads after rain. The best case. Bitumen turns into a mirror for an hour after a shower, and a polarised lens takes the sheet of white glare off it so you can see what's underneath — potholes, painted lines, the greasy bit at the apex.
Anything coastal. Sand and water are flat, bright, horizontal reflectors. A beach run or a coastal ride in unpolarised lenses is squinting with extra steps.
Low sun. Early and late, when the sun sits at windscreen height and every car in front of you is throwing light back at your face.
Long exposed kilometres. Less glare means less squinting, and less squinting over three hours is a real difference in how your head feels at the end.
Four times it's the wrong lens
Now the part most brands leave out.
1. Reading a screen mid-effort. LCD and LED screens put out light that's already polarised. Put a second polarising filter in front of it at the wrong angle and the screen goes dark, or blotchy, or rainbow-streaked. Bike computers, GPS watch faces, your phone at the lights, the pump display at the servo. Tilt your head and it comes and goes. If you live off your Garmin numbers, test your lenses against that screen before race day — it varies by device.
2. Reading a slick surface. This is the one worth taking seriously. The way you spot a wet or icy patch on the road is the sheen coming off it — that's glare doing you a favour. Polarisation cuts exactly that signal. On a fast descent, or a shaded corner still damp at 7am, you lose some of the warning that the surface has changed. It doesn't make polarised lenses a bad choice for riding, but it does mean you don't get to switch your brain off in the cold.
3. Windscreens and laminated glass. Toughened glass has internal stress patterns you normally can't see. A polarised lens makes them visible as blotches and rainbow moiré. Mildly annoying in a car, genuinely distracting through a big shopfront window mid-run.
4. Flat light and dark mornings. This one's a bit of a trick, because the real culprit isn't the polarisation — it's the tint. Polarised sports lenses are nearly always built dark, Cat 3, because that's what they're for. At 5:45am under heavy cloud, a Cat 3 lens is too much lens. The filter isn't the problem. Reaching for the wrong pair is.
So what do you actually buy
For most Australians who run or ride in daylight: polarised, Cat 3, UV400. That covers bright sun, wet roads, coastal glare and long exposed days — the overwhelming majority of what you'll do. The exceptions above are worth knowing, not worth building your purchase around.
That's the spec we build to. The RYZE Glacier is the running frame — polarised, UV400, Cat 3 at 17% VLT, in a clear crystal frame that more or less disappears on your face. If you're mostly on the bike and want more coverage against wind and side glare, the SHYFT Glacier is the same lens in a taller, fuller wrap that holds its shape under a helmet. Both $100.
The lens spec is only half the job, though. A perfectly specced pair that shifts every time your foot lands is worse than a cheap pair that stays put — which is a separate problem worth solving properly.
Bright sun. Right lens. Easy decision.