25/11/2015 9:56 AM AEDT | Updated 15/07/2016 12:51 PM AEST

The Science Of Sunglasses: Why Darker Shades Don't Mean Better UV Protection

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Portrait of woman in sunglasses

When it comes to picking the best sunglasses for summer, there are a few shady facts to be aware of.

For starters, darker lenses don't equal better sun protection. Ophthalmic surgeon Gerard Sutton told The Huffington Post Australia there was a difference between blocking out light and filtering out harmful UV rays.

"UV is invisible so it doesn't matter how dark or what colour sunglasses are," Sutton told HuffPost Australia.

"You can have a very dark pair of cosmetic glasses, and you might feel as though there's not much light getting in, but it's not visible light that's potentially dangerous, it's UV that you want to filter out."

He said lighter lenses, whether they were grey, green, brown or any other colour, were just as effective.


Harmful UV rays are invisible, so how do you tell if your sunglasses are effectively filtering it? Sutton said the answer was in the packaging.

Any eyewear sold in Australia has a category rating from 0 to 4, with 4 being the best and catergories 0-1 being fashion spectacles providing limited protection.

"Anything from a category 2 up is good," Sutton said.

"The Australian standards are really good and effective -- you just need to be a little bit conscious about checking while you shop, and they don't have to cost you a squillion either.

"It doesn't matter if you get a relatively inexpensive pair from the Cancer Council or a pair of Giorgio Armanis as long as they've got good UV protection."

Sutton also said bigger was better when it came to frames.

"They provide more protection -- wrap-arounds are the best," Sutton said.

Sutton also said Aussies were especially keen on being out in the sun.

"Here in Australia, we live an outdoor lifestyle so we need to be a a little bit more aware," Sutton said.

"I'd never advise people to not go surfing or swimming or playing sport but because we live outdoors, we are at greater risk that someone living in, say, a wet part of London."