What do I need to know about eyeglass lenses?

Linda Eigner

Snowboard goggles and ski goggles are fulfilling more and more functions and are part of the basic equipment for every winter sports enthusiast. In order to not only keep a clear view on the slopes, but also in the lens technology, we have summarized the most important properties relating to colour, shape and function for you. The NAKED Optics Lens Guide turns you into a snow bunny with the best vision.

What does Light Transmission (VLT) mean?

The individual and unusual designs of the snowboard and ski goggles must primarily match two things: the outfit, but above all the weather and visibility conditions. Which glasses or which glass fits but under which circumstances? Here the light transmission is perfect for orientation. The VLT value , also known as visible light transmission, shows how much light can penetrate the lens. The higher the percentage, the more light can penetrate through the lens. A high level of light transmission optimizes visibility, especially in poor conditions such as snowfall or fog. In turn, a low VLT value means that less light can penetrate through the lens. There are even lenses with 100% light transmission. These are clear lenses. In order to get along better with the other VLT values, the values ​​are divided into different categories (CAT). Each category is suitable for specific weather conditions. The following table serves as a guide:

Light Transmission (VLT)

Category (CAT.)


Suitable for


CAT. 0

Very little light

night skiing


CAT. 1

Little light and bad conditions

snowfall and fog



Variable to normal conditions

Cloudy and partly sunny weather


CAT. 3

Normal to fair conditions

bright daylight


CAT. 4

Very nice conditions

Bright sunshine / glaciers


Cylindrical vs Spherical Lenses: What's the Difference?

Have you ever heard of cylindrical and spherical glasses? These are the two traditional lens shapes found in snowboard goggles and ski goggles. Cylindrical lenses are curved horizontally and flat vertically. In contrast, spherical lenses are curved horizontally and vertically. This lens is based on the shape of the eyes and allows for a larger interior volume. This gives you a wider field of vision and the air can circulate better. Winter sports goggles with a spherical lens are now more and more common on the slopes as they are a fashionable eye-catcher. The lens shape also plays an important role in finding the best view.

How does lens changing work with a magnet system?

The weather can change as quickly as the gondola takes us from the valley to the summit. From bright sunshine to fog in just a few seconds. Ski days like this are also part of winter fun. In order to be able to adapt to the sudden changes in the weather and to keep track of things, you need to adapt to the conditions in a matter of seconds. This is exactly what is guaranteed by a SnapTech magnet exchange system. The ski goggle lens can be exchanged in just a few simple steps and switched from fair-weather lenses to bad-weather lenses. So even a snowfall can't keep you from casual downhill turns. The following NAKED Optics goggles are also equipped with the magnetic system: The NOVA, The STORM, The TOOP EVO and The FORCE EVO.

How do I prevent ski goggles from fogging up?

There is probably nothing more annoying than fogged up ski goggles on the slopes. Why this happened at all is explained easily. It's cold outside and warm inside. If the air is not circulated sufficiently, then the lens will fog up. To prevent this, most ski goggles have two lenses. Together with an anti-fog coating, annoying fogging can be prevented.

NAKED Optics Insider Tip: In contrast to the other models with an anti-fog coating, our ski goggles The NOVA and The STORM are equipped with a super anti-fog coating. This makes the goggles 300% more resistant against fog. 

Are polarized lenses better?

When it comes to ski goggles or sports goggles, there is no way around the term polarized lenses. You can read what polarization actually means and what advantages and disadvantages there are in our blog article.

Photo: Florian Dorn


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