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Gletscherbrille. Foto: Ortovox

What are glacier glasses?


A buyer’s guide to glacier glasses
Adventuring on glaciers requires the right equipment

At first glance, glacier glasses may look like somewhat large sunglasses. But, they’re typically more expensive. Why? What can glacier glasses do that other sunglasses can’t? What makes glacier glasses so special and how do they defer from other sunglasses?

Questions upon questions… Here come the answers!

Regardless of whether you’re on a glacier, in the desert or on the water – when exposed to the sun for a long time, not only should you protect your skin but also your eyes. We usually remember to put on sun screen but we tend to forget that our eyes are also prone to sun damage.

Filter categories and UV protection

While some sunglasses simply let through less light thanks to their tinting, quality glasses actually filter UV radiation along with visible light and therefore protect the eyes against damage. In addition, there are five different lens categories that allow different amounts of light to pass through:

  • Category 0: 80-100% light transmission
  • Category 1: 43-80% light transmission
  • Category 2: 18-43% light transmission
  • Category 3: 8-18% light transmission
  • Category 4: 3-8% light transmission

On glaciers, light comes from both above and below (due to the sun’s reflection on the snow and ice), so you need glasses with a minimum of category 3 lenses and optimal would be ones with category 4 lenses.

Because the highest-category glasses only let 3-8% of the light through, they are optimal for use on glaciers. However, this is usually too low for your journey to the mountain. Especially whilst on the road, the 3% light transmission would prevent you from seeing everything. For this reason, glacier glasses are not permitted in road traffic.

Now, you may think that you need to bring along a second pair of sunglasses with you, but that’s not at all necessary!

BOLLÉ-Cobalt Phantom S2-3 – Sunglasses with tinted lenses

How do self-tinting lenses work?

Some glasses feature interchangeable lenses, so you get to keep the glasses on at all times and simply need to change the light lenses to dark ones and vice versa depending on the light conditions. With these, there’s no need to purchase additional frames.

However, there are glasses that can change categories on their own. These so-called photochromic (or phototropic) glasses are equipped with light-sensitive molecules that either lighten or darken the lenses depending on the strength of the UV radiation. As a result, you don’t need to purchase any additional lenses!

Although these glasses sound like the perfect solution, there are still a few things to keep in mind. Self-tinting glasses do indeed change their percentage of light transmission, however not in the wink of an eye.

While the darkening process takes 15-30 seconds, they may require 5-10 minutes to become lighter.

What’s better: self-tinting or interchangeable lenses?

This is an individual decision you will need to make. An advantage of having photochromic lenses is that you’ll always have them with you and there’s no way of forgetting your interchangeable lenses at home or in the car.

A buyer’s guide to glacier glasses
Self-tinting glasses adapt to changing light conditions.

One may also argue that the darkening process is more important for protecting the eyes than the opposite. Plus, changing your lenses requires about 15-30 seconds (putting down your backpack, finding the lenses, changing them, packing everything back up). As a result, your eyes are unprotected during this time. With self-tinting lenses, everything happens automatically.

But, one advantage of interchangeable glasses is the extended range of lenses available. While the self-tinting glasses usually remain in categories 2-4, interchangeable lenses allow you to have lenses in every category.

However, since our focus right now is on glacier glasses, we will only deal with glasses in categories 3 and 4. Whether or not you need interchangeable lenses is a matter of taste. Being able to change the (self-tinting) lens is a more useful feature when you are back down from the glacier but needed a higher protective category at the top.

Not only is the range of the lens category important in your glacier glasses selection process but there are also other special features that you should look out for. Here they are:

The BOLLÉ-Cobalt Polarized S3 boasts an anti-fog coating

Eye coverage

Glacier glasses should definitely protect the entire eye against sunlight. The light comes from everywhere, so great glacier glasses, such as the Julbo Explorer Cameleon, feature additional coverage at the upper, lower and sides of the glasses to prevent direct contact with the sun.

Other practical features include ventilation holes and a sweat blocker, like on the Julbo Trek Spectron 4. Whilst mountaineering, you’ll probably break out into a sweat and once you take a break, your head will quickly cool down.

As a result, ventilation holes will remove the warm air and sweat will then be minimized. Plus, the sweat blocker will prevent the sweat from going down your forehead and into your eyes.

In addition, since both the temperature and humidity level on the inside of the glasses are much higher than on the outside, your glasses are at a high risk of fogging up. To prevent this from happening, glasses like the BOLLÈ – Cobalt Polarized S3 feature an anti-fog coating. So, when shopping around for glacier glasses, you should definitely make sure that the glasses have this coating!

Please note: If the glasses ever steam up, do not rub the glasses with your gloves because this can damage the coating. You should rather dab the lens with a lint-free cloth!

Polarised lenses

You should never conquer a glacier without the appropriate eyewear.

Polarised lenses are also very practical. Polarised lenses only partially let reflected light through so that the light reflected from snow on the ground isn’t perceived as brightly and won’t blind you. However, contrast becomes more apparent, since most of the so-called stray light is filtered (this is also polarised). The Julbo MonteBianco polarised glasses actually ensure that the desired effect is achieved.

Mirrored lenses

In addition, glasses, such as the Explorer L Alti Arc 4 from Julbo feature mirrored lenses. These have two basic functions:

Firstly, they keep confusing reflections out of the glasses’ inner area (and therefore also out of the eye) and secondly, they filter out certain hues of light. So, whilst wearing silver glasses, most of the white light (e.g. light reflected from the snow) is bounced back and you’ll receive more light from other colours, for example the dark areas on a rock or the structure of the blue water.


Another deciding factor whilst looking for sunglasses is the fit. To prevent the glasses from slipping off your head, they should actually fit your head. For example, flexible temples come in handy when you want to secure it on your head, helmet or beanie. Metal temples can actually become a problem for your ears on glaciers because they can cause frostbite.

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