Sunglasses & Eye Protection: What to Check

Written by Vasileios Skouteris MD, FEBO, Ophthalmic Surgeon

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Why do we need sunglasses?
What to check before you buy
Sunglasses for children: what is different?
When to see an ophthalmologist
Frequently Asked Questions

Sunglasses only provide real eye protection when they fully filter out UVA and UVB ultraviolet radiation, which is indicated by the UV400 label. A dark lens colour is not a sign of protection. The CE mark, the filter category, the size of the frame and, for children, durability also matter.

Why do we need sunglasses?

Ultraviolet radiation cannot be felt, but exposure to it adds up over a lifetime. In Greece, with long hours of sunshine and strong reflection from the sea, sand and white surfaces, this is an issue for almost the whole year. Chronic exposure has been linked with:

Pterygium, a fleshy growth of the conjunctiva towards the cornea, common in people who spend many hours in the sun, at sea and in the wind.
Earlier onset of cataract, mainly of certain types.
Pinguecula, a yellowish bump on the white of the eye, and skin cancers of the eyelids.
Photokeratitis, an acute and painful “sunburn” of the cornea after strong reflection from snow or water.

For macular degeneration the evidence is less clear. A link with sun exposure has not been definitively proven, but protection from bright light is considered sensible prevention, especially for people who already have early findings or a family history.

What to check before you buy

UV400 label or full UV protection

The UV400 label means that the lenses filter radiation with a wavelength of up to 400 nanometres, in other words the entire UVA and UVB spectrum. This protection has nothing to do with how dark the lens is, nor necessarily with the price. If you are unsure about a pair you already own, most opticians can check it with a special meter in a few seconds.

CE mark and filter category

In the EU, sunglasses must carry the CE mark and state a filter category from 0 to 4, in line with the EN ISO 12312-1 standard. The category shows how much visible light the lens reduces, not how much UV protection it offers.

Category	Visible light transmitted	Suitable use
0	Over 80%	Indoors, overcast days, mainly cosmetic use
1	43-80%	Low light
2	18-43%	Moderate sunshine, city use
3	8-18%	Strong sunshine, the sea, the Greek summer
4	3-8%	Mountains, snow, sailing. Not suitable for driving

For most summer activities in Greece, category 3 is the most practical choice. Category 4 is so dark that it is not permitted for driving.

Why a dark lens without a UV filter is worse than none

Behind a dark lens, the pupil dilates to let in more light. If the lens does not filter ultraviolet radiation, more UV reaches the inside of the eye than if you were wearing no glasses at all. That is why uncertified sunglasses from market stalls or kiosks are not a harmless choice, however good they look.

Polarised lenses: what they do and do not do

Polarised lenses reduce strong glare from water, sand, snow or a wet road. They give a more comfortable, clearer view at sea, when fishing and when driving. Polarisation on its own, however, does not mean UV protection, so you still need the UV400 label. On some screens, such as a mobile phone or a car dashboard display, the image may darken or show coloured patterns through a polarised lens.

Does the lens colour matter?

Colour mainly affects comfort and colour perception, not UV protection. Grey lenses distort natural colours the least and are a safe all-round choice. Brown and copper lenses increase contrast and help in changing light, while green lenses sit somewhere in between. Yellow or orange lenses are designed for low light and are not suitable for strong sun. Gradient lenses, darker at the top, are practical for driving but protect less against glare coming from below, for example at the sea.

Size, fit and lens quality

Large lenses or wraparound frames stop light getting in from the sides and above. A hat with a brim reduces exposure significantly as well. Check that the lens does not distort the image: look at a straight line and move the glasses slightly. If the line “ripples”, the lens is not of good optical quality and may tire your eyes. If you wear prescription glasses, prescription sunglasses or photochromic lenses are a safer and more comfortable solution than clip-ons.

Sunglasses and driving

Categories 1 to 3 are suitable for daytime driving. Avoid sunglasses at night, at dusk and in tunnels, as they reduce visibility dangerously. If car headlights dazzle you badly at night, tinted lenses such as so-called night driving glasses will not solve it. You need an eye examination, because it may be due to an early cataract or an uncorrected refractive error.

Sunglasses for children: what is different?

The natural lens of the eye in children is clearer than in adults and lets more ultraviolet radiation through to the retina. Children also spend more hours outdoors, often when the sun is strongest. When choosing sunglasses for children:

Look for the same UV400 label and CE mark as on adult sunglasses. “Toy” glasses with coloured plastic are not enough.
Choose lenses made of polycarbonate or another shatter-resistant material.
Pick a flexible frame that fits well, with an elastic strap for younger children.
Combine them with a brimmed hat and shade around midday.
For babies under 6 months, the main protection is shade and avoiding direct sun.

If your child constantly squints in the light, rubs their eyes or struggles to see, it is worth having them examined by a paediatric ophthalmologist, as light sensitivity can accompany refractive errors or other conditions.

When to see an ophthalmologist

You need an examination if you develop:

Pain, heavy watering and a gritty feeling a few hours after exposure to sun, sea or snow, which are signs of possible photokeratitis.
A fleshy “patch” on the white of the eye that is growing or becoming irritated.
Gradual blurring or severe glare from lights, especially at night.
Distortion of straight lines or a shadow in the centre of your vision.

You will find more practical seasonal advice in our guide to protecting your eyes in summer.

For a full eye check before the summer, for you or your children, book an appointment at our clinic in Neo Psychiko, Athens.

Frequently Asked Questions

Do expensive sunglasses offer more protection?

Not necessarily. Protection from ultraviolet radiation depends on the lens’s UV filter, not on the brand or the price. An affordable pair with a certified UV400 label and CE mark gives adequate protection. A higher price usually reflects the optical quality of the lens, durability, coatings and design.

Do I need sunglasses when it is cloudy?

Often, yes. A significant amount of ultraviolet radiation passes through clouds, and reflection from water, sand, concrete and snow increases exposure. Even in winter, in the mountains or at the sea, radiation can be high. Sunglasses are useful all year round when you spend hours outdoors, not just in August.

At what age can a child wear sunglasses?

There is no strict age limit. For babies, protection relies mainly on shade, a hat and avoiding the midday sun. Once a child will tolerate glasses, usually after the first year, they can wear children’s sunglasses with a UV400 label, shatter-resistant lenses and a flexible frame that fits properly.

Can photochromic lenses replace sunglasses?

Photochromic lenses darken in response to ultraviolet radiation and usually filter it completely, so they are a good solution for people who wear prescription glasses. Inside a car, however, they darken very little, because the windscreen blocks much of the UV. For long hours at the sea or for driving in strong sun, a pair of prescription sunglasses is more comfortable.

Questions about your case?

Dr. Skouteris will examine you at his practice in Neo Psychiko and explain your options.

Call 210 677 0007 Book an appointment

About the author

Dr. Vasileios Skouteris, MD, FEBO

Ophthalmic surgeon trained at the John Radcliffe University Hospital in Oxford and Fellow of the European Board of Ophthalmology (FEBO).

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