Why you need to wear sunglasses every day, even when it's cloudy: Experts reveal why this surprising advice is NOT overkill... and could prevent serious health problems

Every single morning, ophthalmologist Dr Susan Sarangapani does two things without fail: she applies SPF50 sunscreen on her face, arms and hands — then puts on sunglasses.

While the sunscreen isn’t overly surprising, the glasses, perhaps, are.

Yet she wears these for the same reason — to protect herself, but here specifically her eyes, from the sun’s ultraviolet (UV) rays.

What’s more, she says, she’ll wear them outdoors all year round whether it’s sunny or cloudy.

‘What people don’t realise is that eyes are ten times more sensitive to the sun’s damaging UV rays than skin,’ says Dr Sarangapani, who is a consultant surgeon at Luton and Dunstable Hospital NHS Foundation Trust and private OCL eye clinic in London. ‘And not protecting them can lead to problems — from excessive blinking due to light sensitivity, through to serious long-term conditions that can cause sight loss.’

‘What people don’t realise is that eyes are ten times more sensitive to the sun’s damaging UV rays than skin,' says Dr Sarangapani

These include age-related macular degeneration (AMD), where the cumulative effects of UV exposure contribute to the deterioration of the middle part of the vision — and cataracts, where the eye’s lens becomes cloudy.

‘The rays can also increase your risk of cancer both on the delicate eyelid skin and the eyeball itself,’ adds Dr Sarangapani.

While we all know about the risk of skin cancer, ‘people are still shocked when I tell them to wear UV-blocking sunglasses whether it’s a hot sunny day or not’, she says.

Much of what we know about all this comes from Australia which, because of its high levels of UV year-round, has invested years of research into the effects of sun damage, and are decades ahead of us in terms of the impact on eye health.

Back in 2007, the Australian Cancer Council added the words ‘seek’ and ‘slide’ (seek shade and slide on sunglasses) to its famous ‘Slip, Slop, Slap’ campaign, launched in the 1980s to tackle Australia’s unfortunate position of having the world’s highest rates of skin cancer. The decision came about after research by renowned Australian ophthalmologists, Professors Hugh Taylor and Paul Mitchell, in the 1990s.

‘They worked with the Melbourne Visual Impairment project and the Blue Mountains Eye study — population-based studies looking at the prevalence, severity and progression of common eye disorders [such as cataracts, glaucoma and AMD],’ says David Mackey, a professor of ophthalmology at the University of Western Australia.

Professor Taylor had also carried out work on sunlight and eye disease in Australia which showed that indigenous Australians living closer to the equator had higher rates of cataract and pterygium, when lesions appear on the white of the eye, and that’s also linked to an increased risk of skin cancer.

Another study, published in 1989, which looked at the effect of sun exposure on fishermen on Chesapeake Bay in the US over time, found a link between their UV exposure and the development of cataracts, pterygium and skin cancer.

This understanding is particularly important for children, whose eyes are at a higher risk of UV damage. With larger pupils and clearer lenses, due to younger and healthier eyes, up to 70 per cent more UV reaches the retina than in an adult’s eye.

This has led to the position in Australia now where eye protection is deemed to be as important as skin protection — its impact can be seen in 2021 research published by Professor Mackey and his team into the effectiveness of the sun protection campaign since sunglasses were added — this showed surgery for pterygium is falling, with a 47 per cent decline nationally, says Professor Mackey.

Every single morning, ophthalmologist Dr Susan Sarangapani does two things without fail: she applies SPF50 sunscreen on her face, arms and hands — then puts on sunglasses

‘I for one certainly practise what I preach and for eight months of the year, when UV rays are strongest, wear a hat and sunglasses,’

However, in the UK, we still seem worryingly ignorant about these risks, experts say.

Dr Paramdeep Bilkhu, clinical adviser for the College of Optometrists, says: ‘Some people still think it needs to be hot for high UV levels — this isn’t strictly true, as the levels you’re exposed to also depend on altitude and reflective surfaces, such as water, which the rays bounce off.

‘The sky doesn’t have to be cloudless, either,’ he adds. ‘UV rays can penetrate cloud cover. The UV risk to eye health is real - even out of summer months.’

The sun’s intensity is measured by the UV Index, usually given in weather broadcasts or available on the Met Office website based on your location. This index is graded from 1, ‘low’, to 11+, ‘very high’ – but anything above 3 (graded ‘moderate’) can do damage, so that’s when you should wear sunglasses.

‘While we protect our skin from these rays with clothing or sun block, our eyes are continually exposed,’ says Dr Bilkhu.

‘Also, as with skin colour, lighter eye colours such as blue are more prone to UV damage than brown, because they have less pigment to absorb the rays.’

There are two types of damaging rays: UVA and UVB.

‘UVA rays pass through the front of the eye to the lens, and there’s a possible link between exposure to UVA and macular degeneration and uveal [i.e. eye] melanoma,’ says Dr Bilkhu.

‘UVB rays carry more energy and are absorbed by the cornea [the clear part at the front of the eye] and exposure can lead to what is, effectively, eye sunburn.

‘This often occurs within several hours of exposure and can be painful, causing red, light-sensitive and watery eyes, and may blur your vision,’ says Dr Bilkhu.

‘Fortunately it’s usually temporary and anti-inflammatory eye drops can help.’

However long-term exposure to UVB can cause damage to the cell DNA, increasing the risk of cancer, adds Dr Sarangapani.

This can affect the eyelid, where the skin is the thinnest and particularly vulnerable, or on the eyeball itself, although this is rare (with around 851 cases diagnosed annually in the UK).

Uveal melanoma is the most common form of eyeball cancer, affecting the uvea — the middle layer which includes the iris — and can be deadly. Symptoms include a change in pupil size or shape, blurred vision or pain in the eye. ‘Unfortunately, it can result in removal of the eyeball,’ says Dr Sarangapani.

‘Yet a simple way to prevent this is to wear UV-blocking sunglasses,’ she adds. ‘I wear them all year round, but advise patients to wear them at least from mid-March to mid-October.

‘Also protect children most: babies under six months should be kept out of direct sunlight altogether. Over six months, babies can wear goggle-type glasses which are on an elasticated band so they can’t take them off. From age five, they can wear normal sunglasses.

When you wear them during the day is also important.

‘For skin protection, the advice is to avoid sun from 11am to 3pm when UV intensity is strongest,’ says Dr Bilkhu.

‘But with sunglasses, it’s important to wear them in the early morning and late evening, too. This is when the sun’s lower in the sky and your eyes can be dazzled by the glare which means they’re being hit by UV rays.’

But you must also wear the right kind of sunglasses.

‘The easiest way to get it right is to see your optician for advice,’ suggests Dr Bilkhu, who wears sunglasses when UV levels are high or if the sun is low in the sky — no matter the time of year.

Otherwise, there are easy rules to follow.

First, look for the European Standard CE or UKCA mark. This means the lenses conform to health and safety standards that ensure they protect against UV light.

Second, don’t assume a darker lens (or, indeed, premium price) offers higher levels of UV protection.

‘The darkness of the lens has nothing to do with UV protection, the tint simply reduces the brightness of visible light that reaches your eyes,’ says Dr Bilkhu.

If you wear prescription glasses, you can choose photochromic lenses with UV protection — or use clip-on or flip-up sunglasses lenses. Contact lens wearers should choose products with UV filters. ‘However, these only protect the cornea and prevent UV from entering the eye through the pupil — they don’t protect exposed areas of the eyeball or surrounding skin, so additional sunglasses are important,’ says Dr Bilkhu.

‘Wearing sunglasses regularly is such a simple thing to do and it can prevent future avoidable sight loss,’ says Dr Sarangapani.

‘If my colleagues in Australia, who’ve been researching this topic for decades, stress the importance of it, then we must too.’