Anyone who practices high-mountain sports must be aware that they are operating in a risky environment. While the risks linked to the mountains themselves may be obvious, those caused by exposure to the sun at high altitudes are more difficult to understand. Julbo sheds some light on the subject.

1. High-mountain
sun protection
www.julbo-eyewear.com

2. CONTENTS
1. Introduction
2. The dangers of the sun in high-mountain environments
3. The most common disorders
4. Julbo sun solutions

3. Anyone who practices high-mountain sports must be aware that they are
operating in a risky environment.
While the risks linked to the mountains themselves may be obvious, those
caused by exposure to the sun at high altitudes are more difficult to
understand. Julbo sheds some light on the subject.
Since the 1950s and the release of its famous Vermont, Julbo sunglasses
have accompanied expeditions up all the mountains of the world. From
the Antarctic to the Alps to 8,000 m Himalayan peaks, Julbo has honed its
expertise in high-mountain sun protection to become a benchmark brand
in this area.
Julbo shares its experience to make sure you have the best possible
protection for high-mountain environments.

4. 2. THE DANGERS OF THE SUN IN HIGH-MOUNTAIN ENVIRONMENTS
Exposure to solar radiation increases on average by 10% (between 4 and
16%) with every 1,000 m of altitude, and the UVB light it contains is
particularly dangerous.
In addition, the snow often present in the mountains reflects between 80
and 90% of solar radiation compared with 20% on non-snowy ground.
The intensity of solar radiation is therefore 1.5 times greater at 2,000 m
and 2.5 times greater at 4,000 m than at sea level.

5. Exposure will vary depending on the thickness of the ozone layer in the
atmosphere (which acts as a natural filter), the season and the angle of
incidence of the sun's rays.
It should be noted that solar radiation is 25% greater at the autumn equinox
than the spring equinox when the ozone layer is thicker.
The ozone layer varies in thickness depending on where you are in world and
therefore offers differing degrees of protection.

6. The amount of radiation varies as the sun's position changes during the
course of the day. The risks linked to light will therefore also vary.
The angle of incidence of the sun's rays when they penetrate the ozone
layer has a direct effect on the amount of filtration provided by the ozone.
It is for this reason that radiation is strongest between 10 am and 3 pm.

7. It is important to remember that in cloudy conditions the sun is still
dangerous in the mountains.
You should not count on overcast skies to protect you as they provide
only limited filtration. While UV light can be stopped by some clouds
(alto-cumulus), cirrus clouds have no filtration effect at all.
50% of the sun's radiation passes through fog. It is therefore necessary
to protect yourself in the mountains, even when conditions are cloudy.
At high altitude, in overcast conditions, you may frequently find yourself
in the upper layer of the clouds. The radiation here is intense through the
effects of light diffraction. The risks are therefore even higher than in fine
weather.

8. 3. THE MOST COMMON DISORDERS
 Photokeratitis or snow blindness
Cause: Erosion of the epithelium (layer of surface cells) covering the
cornea resulting from extended exposure to intense light (high UVB
radiation).
Symptoms: 4 to 6 hrs after exposure
Pain and "grains of sand" sensation under the eyelids together with
photophobia (pain increased by light).
Conjunctival redness, excessive tear secretion, swelling of the eyelids and
difficulty opening the eyes, as well as intense blepharospasm (involuntary
blinking of the eye).
Treatment: rest in a dark room / eye patch / application of antiseptic eye
wash and ophthalmic ointment.
Avoid eye washes containing anaesthetics.
Contact lenses must not be worn for 4 to 5 days.

9.  Erythropsia
Cause: Exhaustion of the retina resulting from prolonged exposure to
intense light stimulation. This disorder is rarer than snow blindness.
Symptoms: Objects take on an abnormal reddish hue.
Treatment:
● rest in a dark room
● eye patch
● application of antiseptic eye wash and ophthalmic ointment.
Snow blindness and erythropsia do not have long-term after-effects if
treated in time. However, snow blindness can endanger the lives of
mountaineers in high-mountain environments by depriving them of their
vision.

10.  White-out syndrome
Cause: frostbite of the eye or eyelids as a result of being in extremely cold
conditions.
Symptoms:
Initial symptoms: pain, blurred vision, photophobia and excessive tear
secretion, or even total loss of vision.
Later symptoms: reduced visual acuity associated with a loss of
perception of relief and elevation resulting in disorientation and sensations
of vertigo.
Treatment: protecting the eyes from cold and warming them up should
ensure good recovery.

11.  Corneal frostbite
Cause: the temperature of the cornea is between 29 and 36 °C. Extreme
cold and/or snow combined with wind can lead to frostbite of the cornea.
Symptoms: blurred vision, excessive tear secretion, photophobia or even
total loss of vision.
Later symptoms: reduced visual acuity associated with a loss of
perception of relief and elevation resulting in disorientation and sensations
of vertigo.
Treatment: eye patch and gradual passive heating and removal from cold
(2 to 3 days).
Expedition tip: use a warm teabag to heat up the eye.
Warning: corneal frostbite can lead to necrosis and loss of the eye if not
treated correctly.

12. 4. JULBO SUN SOLUTIONS
All these disorders can be prevented by wearing equipment suitable for the
conditions.
Julbo has developed a range of products specially adapted to these extreme
conditions with category 4 lenses, wraparound frames and protective side
shields.

13. 4 // Julbo lenses
In high-mountain environments, a high degree of sun protection is
necessary and you should opt for category 4 lenses.
Julbo offers the following lenses for these conditions:
Cat. 4 mineral lens (VLT*:7%). The must-have product
for glacier frames. The only lens to offer complete
protection in very high mountain environments.
Recommended for individuals sensitive to infrared light
Cat. 4 polycarbonate lens (VLT* :5%). Designed to offer
powerful protection for mountain trekking and
mountaineering
*Visible light transmission

14. 4 // Julbo lenses
Cat. 2 to 4 NXT© photochromic lens (TLV*: 20-5%). The brown
tint and filtration level have been designed to offer the best
performance for trekking and mountaineering. NTS technology
guarantees a constant photochromic range, whatever the
outside temperature
Cat. 2 to 4 NXT© photochromic lens (TLV*: 42-7%).
Lighter than the Cameleon lens and suitable for skiing and
trail running. Offers good protection at low temperatures
in high-mountain environments.

15. 4 // High-mountain sunglasses
High-mountain frames must provide the wearer with optimum protection.
In addition to the category 4 lens, they must offer good protection against
direct and indirect radiation as well as external elements. They must also
be adapted for use in extreme sports.
A good frame must therefore provide:
- Total coverage / protective side shields.
- A pronounced curve.
- Excellent grip.
- Ideally a headcord.

16. 4 // High-mountain sunglasses: EXPLORER
The highest mountains and extreme conditions bring out the best in
these sunglasses developed in collaboration with the elite climbing
school in Chamonix.
The Explorer takes glacier sunglasses to the next level: lenses with
impressive protection, coverage from damaging UV rays, an anti-fog
ventilation system and side shields to stop wind and snow getting in.
Available in an Alti Arc mineral lens, Cameleon photochromic lens
and Spectron 4 polycarbonate lens.

17. 4 // High-mountain sunglasses: TREK
Trek's mission is to provide highly technical but light equipment for
moving fast in extreme environments and achieving optimum
performance.
It combines the fundamental principles of mountaineering glasses with
the lightness and ergonomics of speed sport sunglasses.
The side shields block radiation in high glare environments such as
glaciers and deserts, while the suspended lens ensures clear vision and
good ventilation.
Available with Cameleon or Zebra lenses for optimum protection from
intense solar radiation.

18. 4 // High-mountain sunglasses: BIVOUAK
The Bivouak has been designed to cope with a huge variety of terrain
and is suitable for every outdoor activity.
With wide Cameleon or Zebra lenses and optimum coverage provided
by the magnetic side shields, these glasses offer protection specifically
adapted to mountain use.

19. 4 // High-mountain sunglasses: MONTEROSA/MONTEBIANCO
With removable side shields, wide lenses and ergonomic design,
MonteRosa and MonteBianco offer total protection.
These frames combine style and simplicity with lightness, technical
excellence and outstanding protection, giving users high-performance
mountain glasses that are also suitable for everyday use.

20. 4 // High-mountain sunglasses: TENSING M/L
The ultra-wrap profile of these glasses provides ideal protection against
high-altitude sun while the side openings guarantee superior ventilation.
These glasses offer excellent value for money and have been designed
so that amateur mountaineers can enjoy their sport in complete safety.

21. Julbo
Rue Lacuzon
39400 Longchaumois - France
Tel.: + 33 (0)3.84.34.14.14
info@julbo.fr
www.julbo-eyewear.com
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