Polarised vs Non-Polarised Sunglasses: What's the Difference?

If you've ever squinted at the road on a bright afternoon, or struggled to see past the shine on the sea, you've met glare. Polarised lenses are built to deal with it. Here's what they actually do, and whether you need them.

What is glare, and how do polarised lenses stop it?

Normal sunlight scatters in every direction. When it bounces off a flat surface like water, a wet road, sand or a car bonnet, a lot of that reflected light lines up horizontally. That concentrated, flat light is what you see as glare.

A polarised lens has a filter with a vertical pattern built into it. It lets normal light through but blocks most of that horizontal reflected light. The result is less squinting, better contrast and clearer detail.

Polarised is not the same as UV protection

This is the most common mix-up. Polarisation deals with glare. UV protection deals with the invisible ultraviolet rays that can damage your eyes. A lens can be polarised without blocking UV, and a lens can block UV without being polarised. Look for both: polarised lenses and a UV400 or 100% UV protection rating. We explain UV400 in What does UV400 mean?

When polarised lenses make the biggest difference

• Driving. They cut the shine off the road, wet tar and other cars, especially with the low sun on early and late commutes. See our guide to the best sunglasses for driving.
• The beach and the water. Glare off the sea and the sand drops away, and you can often see into the water instead of only the reflection on top of it.
• Fishing, paddling and boating. Seeing below the surface is a real advantage.
• Long days outdoors. Less squinting means less tired eyes by the end of the day.

When polarised lenses can get in the way

• Some screens. Phone screens, car displays, fuel pump displays and ATMs can look darker or even blank at certain angles, because many screens use polarising filters of their own. Tilting your head usually fixes it.
• Some car windows. You may notice faint patterns or rainbow marks in toughened glass, such as some rear and side windows.
• Pilots and some machine operators are often advised not to wear polarised lenses, because they can make instrument displays harder to read.

How to tell if your sunglasses are polarised

Look at a phone or laptop screen through one lens, then slowly rotate the sunglasses 90 degrees. If the screen goes noticeably darker or black at one angle, the lenses are polarised. You can also look at a shiny surface like a car bonnet or a swimming pool and tilt your head. If the glare fades in and out, they're polarised.

So which should you buy?

For most people in South Africa, spending time on the road, at the beach or outdoors in strong sun, polarised is the better choice. The difference is something you notice from the first drive.

Every pair in the Ombrox range is polarised. A few places to start:

• Aurora: green-blue mirror lenses for beach and water days.
• Noir: neutral grey lenses that keep colours true. A great everyday and driving pair.
• Latitude: a lighter tint for overcast days and softer light.

Shop all six polarised styles.