Not all sunglasses are created equal.
In fact, experts say wearing some sunglasses can be worse for your eyes than wearing none at all.
The most important thing is to check your sunglasses are rated two or above in Australia’s safety standards – and we’ll explain why later.
But first, let’s look at why protecting your eyes from the sun is so important.
Dr Jason Yosar, an associate lecturer at the University of Sydney’s Save Sight Institute, fact-checked the importance of wearing sunglasses for an article in The Conversation.
Dr Yosar said although brief exposure to UV will not usually cause symptoms, prolonged or intense exposure can be very damaging.
It causes a condition called photokeratitis, which is essentially sunburn to the cornea.
Recovery from photokeratitis usually takes up to 72 hours, he said, but repeated exposure can lead to serious eye conditions like cataracts, macular degeneration and cancer.
“Although less common, chronic UV exposure is associated with increased rates of certain types of eye cancers,” Dr Yosar said.
“These are: Squamous cell carcinoma of the conjunctiva, melanoma within the eye, and skin cancers of the eyelid and around the eye where people do not routinely apply sunscreen.
“Treatment of these cancers may sometimes require surgical removal of the entire eye.”
Maximise your protection
The damage the sun can do to the eye is disturbing, but there is something you can do to minimise your risk.
The head of prevention at Cancer Council, Adjunct Associate Professor Craig Sinclair, recommends wearing wraparound sunglasses and a wide brimmed or bucket hat whenever the UV rating is three or above – which is usually right through summer in Australia.
“If you have a hat combined with glasses, that provides the best protection of all,” he said.
Professor Sinclair explained the difference between UV exposure and sun exposure to The New Daily.
“The sun is made up of visible light, which is the light that we see [and] ultraviolet radiation, which is radiation we don’t see,” Professor Sinclair said.
“Each makes a contribution to our health in different ways. But like with our skin, it is the UV radiation component that we are most concerned about when it comes to our eyes.
“Whenever we are out in conditions where the UV is three or above, essentially right through the summer months in particular, it is valuable to have eye protection,” he said.
How to choose your shades
Ophthalmologist Dr David Robinson said it is important to choose the right ones, as not all sunglasses effectively protect your eyes.
“Sometimes wearing sunglasses can actually be worse than not protecting your eyes from the sun at all,” Dr Robinson said.
“It is imperative that consumers choose their sunglasses based upon their level of protection, rather than fashion or false information.”
Professor Sinclair said every pair of sunglasses sold in Australia must provide a UV filter rating from 0 to 4 under the Australian/New Zealand Standard.
He advises always looking for sunglasses that have an Australian standards label on them, because plenty of cheap pairs on the market don’t meet the standards.
The label is usually a sticker, or a swing tag, and should be affixed to the glasses in some way.
Categories zero and one are not considered sunglasses because they offer very little sun protection, while categories two to four offer an adequate UV filter.
Note: A category-four lens should not be worn while driving as they are especially dark.
Also, keep in mind that this standard is for Australia and New Zealand, which means extra caution should be exercised when you buy online from overseas.
The standards also only came into place in 2017, so some of your old pairs may not meet them.
Why some pairs are worse than none at all
“Sunglasses which do not filter out UV light actually result in an elevated melanoma risk to the back of the eyes,” Dr Robinson said.
This is because when it is dark, our pupils expand to let in more light and help us see better – and wearing dark-tinted glasses tricks our eyes into reacting in the same way.
Without a good filter, more UV light is allowed into the back of the eye as our pupils expand, which can increase the risk of developing melanoma at the back of the eye.
Cancer Council recommends wearing wraparound sunglasses for full eye protection, and a wide-brimmed hat can offer extra protection.
Dr Robinson said big sunglasses can also be beneficial, because the large lenses cover more of the delicate under-eye area and lower lids.
What about prescription glasses?
Prescription glasses do not automatically come with UV protection and are not included under the Australian standards.
Professor Sinclair recommends adding a UV filter when buying prescription glasses.
If you spend a lot of time outside, it may also be worth buying a good pair of sunglasses that can be adjusted to your prescription, he said.
And staring directly into the sun should always be avoided regardless of the protection offered by your sunglasses.