Trendy shades like these worn by Billie Eilish may be fun to wear, but not all will protect your eyes from the sun. Photo / Getty Images
From pink cat eye shades to oversized sporty frames, sunglasses come in all shapes, colours and sizes. But not all fashionable lenses are safeguarding our vision.
New research from Columbia University has highlighted the major consequences of incorrectly wearing sunglasses and the danger UV radiation poses to the eyes.
And as trendy sunnies grow in popularity, ophthalmologists and optometrists fear that people are buying sunglasses for "the look" and not for their level of UV protection.
For example, glasses styled to sit on a person's nose aren't providing full coverage, exposing the wearer to ultraviolet (UV) radiation which could increase their risk of developing harmful eye conditions.
Additionally, there are possible side-effects to wearing dark-tinted sunglasses indoors, such as eye fatigue, headaches, blurred vision and light sensitivity.
There's more to consider when purchasing a pair of sun-specks than finding a design you like, so here's some tips that may help you find your next pair of vision-protecting shades.
Understanding the harmful effects of UV radiation
UV radiation is a natural energy produced by the sun, but just five minutes of exposure can lead to permanent eye damage and harmful skin conditions.
Cataracts, age-related macular degeneration, cancerous eyelid tumours and cornea and conjunctiva damage are all conditions that could occur as a result of UV overexposure.
Ophthalmologist and eye surgeon Dr Alina Zeldovich told news.com.au 80 per cent of UV damage to the eyes happened in childhood.
"There's a silent UV epidemic affecting children," she said. "Children are a particularly vulnerable group that need to be protected with properly protective sunglasses."
Additionally, those with blue, hazel and green eyes are more susceptible to UV damage as there is less pigment to protect them compared to people with dark coloured eyes.
According to Cancer Council's SunSmart campaign, Australia has some of the highest UV levels in the world due to the country's proximity to the equator, clearer skies and less pollution.
Because of this, Specsavers' Head of Optometry Professional Services Dr Joe Paul said it was important people protected themselves from the sun at all times when outside.
"It's critical that we protect ourselves when outdoors, not only in well-known high sun exposure environments like the beach, but also during those more incidental times in the sun like when collecting mail, waiting for a bus or taking the dog for a walk," he told news.com.au.
The World Health Organisation (WHO) measures UV levels on a scale from 0, which is considered "low", to extreme levels of 11 plus, through its Global Solar UV index. When levels are three or higher, sun protection is recommended.
When you should (and shouldn't) be wearing sunnies
While sunglasses are critical to protecting your eyes in the summer, keeping a pair handy in the winter months is just as essential.
Skin cancer detection organisation Molemap said up to 80 per cent of the sun's UV rays can filter through the thickest cloud cover, which means sun protection is still critical on an overcast day.
"If you're frequently out in environments where UV radiation is intensified, such as the glare reflected from snow, the ocean or even concrete, it's even more important to protect your eyes," Paul said.
"Excessive exposure through these activities can lead to a burn on the front surface of your eye, much like how your skin reacts in a sunburn when subjected to strong sun without protection."
Meanwhile, for those wondering whether it is appropriate to wear sunglasses inside, it's recommended that only those with certain medical conditions should be using sunnies in an indoor environment.
"When you're indoors and in poor lighting, your pupil will dilate, allowing more light into the eye and therefore allowing better contrast sensitivity and vision," Zeldovich said.
"So when you've got dark sunglasses, that happens less and so it will make the vision worse."
Alternatively, wearing sunglasses at night is not recommended as it will affect your quality of vision.
Zeldovich also strongly advises against driving with sunglasses in the evening and said proper Australian or New Zealand standard category three glasses will have a warning against night usage for this purpose.
While you can purchase sunnies from almost anywhere, you need to be wary of knock-offs that don't meet Australian and New Zealand standards.
The Royal Australian and New Zealand College of Ophthalmologists (Ranzco) recommend wearing close-fitting, wraparound-style sunglasses that meet category two, three or four Australian standards.
Paul recommends purchasing your frames from an optometrist, who have a number of designer brands, or a reputable retailer.
"For the best kind of protection, wear sunglasses that have polarised lenses as they provide superior vision in bright light by eliminating 99.9 per cent of horizontal glare, while also providing 100 per cent UV protection," he said.
It's also advised to purchase frames that fit your face, not only as it will compliment your face's structure, but it will also ensure that unnecessary UV light is properly blocked out.
"Not all sunglasses are the same and in fact, ill-fitting sunglasses can allow more UV light into the eye at virtue of their design," Zeldovich said.
"What happens when you put a pair of ill-fitting sunglasses on, or fashion sunglasses … is it actually shuts off your natural reflex so the eyes are tricked into being relaxed.
"So you're no longer squinting and protecting your eyes and all that extra UV is allowed to get to the eye."
As a guideline, Zeldovich said if your sunglasses sit away from the eye and you can fit a finger between your glasses-lens and your eyeball, UV light will be coming in.
If your glasses have a wire frame and you're finding them a bit loose or they keep sliding down your nose, you can go to most optometrists to have them adjusted, usually free of charge.
Final tips for sun protection
While proper sun-protective eyewear is important, there's more you can do to protect yourself from harmful UV rays.
Sunscreen is critical to protecting your skin and preventing cancer, but Paul said a lot of people fail to properly apply it to their eyelids and around their eyes.
"While the eyelid is designed to protect the eye, the skin is very thin and contains fragile tissues that can be damaged by UV light so it's important to make sure you apply sunscreen to your eyelids and reapply it every two hours," he said.
Wearing a broad-brimmed hat will also provide additional shelter to your eyes.
It's also recommended to keep in mind how much time you'll spend in the sun and to seek shade if you need to be outside for a long period of time.
Regular eye checks are pivotal to optimising your eye health as your optometrist or ophthalmologist can address any conditions or potentially emerging issues that may arise in the future.
"We recommend that you get your eyes tested every two years, or every year if you're over the age of 65," Paul said.