Why sunglasses are so important in winter

Hat, gloves, scarf: when we think of winter, all of these essential accessories come to mind. But relatively few people think to add sunglasses to that list. Sunglasses are more of a summer accessory, right? Wrong! It's at least as important for us to protect our eyes in winter as it is during the warmer months. That's because UV radiation, which is so dangerous for our eyes, has a particularly aggressive effect from November to March.

In summer, sunglasses are an essential part of your outfit. That's not only because they look stylish, but also because they protect eyes from bright light. However, what many people don't realise is that damaging UV rays are much more dangerous in winter than in summer. In summer, green surroundings only reflect about 6% of light. For snow, though, that figure is nearly 95%. Only sunglasses with high-quality lenses provide eyes with effective protection against eye inflammation or more serious conditions. This is because sunlight, which contains high levels of UV energy, can cause damage to the retina. All of this means that money spent on high-quality sunglasses is a wise investment.

• The CE symbol is important. This marking guarantees that the product provides at least the minimum standard level of protection. An EU directive specifies that this must be at least 380 nm. At this level, however, 78% of the radiation is still absorbed by the eye.
  
• Because of this, prescription spectacle lenses should ideally offer broad spectrum UV protection above 380 nm. Only lenses with this level of protection can filter out all dangerous UV waves.
  
• The sunglasses need to be sufficiently large, and they also need to fit the size and shape of your face. This is the only way to prevent light from entering the eyes from the side or from above.
  
• The absorption factor plays an especially important role. It needs to be sufficiently high. How dark the prescription spectacle lenses need to be depends on personal preference, as well as the sunglasses' range of application, the area in which they will be worn, the type of sport being carried out, and on other factors. An optician can provide advice on this.
  
• It's best to buy sunglasses at an optician's store. Random samples show again and again that spectacles sold by street vendors bear forged quality marks, and can cause health damage.

It's also important to choose the right colour for the sunglasses' lenses. Lenses are graded in protection classes or categories. Yellow, green and blue lenses are not recommended for use in winter. They offer a protection class of only 0, 1, or 2, or belong to category S0, S1, or S2. Grey and brown lenses are advisable for winter use. They should belong to protection class 3, or category S3. They even provide sufficient protection in snowy conditions high up in the mountains. Protection class 4 or category S4 lenses are available for extremely sensitive eyes. However, prescription spectacle lenses in this category are only necessary in cases where UV radiation levels are extreme; they may not be used while driving.

A good pair of sunglasses should also offer an adequate level of protection against blue light. This is because blue light can damage the macula, the point in the eye where vision is at its sharpest. If you already have a pair of sunglasses and aren't sure how much blue light they block out, you can ask an optician to test them for you.

An extra tip for winter sports: if you wear spectacles, you should either have ski goggles made up individually to suit your prescription, or buy ski goggles which are large enough for you to wear your own spectacles underneath them. Some models feature foam supports which are ideal for spectacle wearers, and have extra room at the side to accommodate spectacle frames. These offer a good fit, and no pressure is put onto the spectacles under the ski goggles. Ski goggles should be closed at the sides in order to offer protection from draughts.