I have been putting the Julbo Dirt sunglasses through the paces from close to a year now while mountain biking. They have dealt with wind storms, rain, snow, and light varying from the bright desert, to the dark woods, and everything in between. They have gotten bounced around while riding through rock gardens, ridden at Mach 1, been dropped on the ground a number of times and been worn under assorted helmets (even full face). They have turned out to be comfortable, durable, fog free, and offer excellent wind protection, great varying light capabilities and superb optical clarity.

Julbo History
Julbo was founded in 1888 by Jules Baud in a little town close to Morez France, which resides in the Jura Mountains. The company has 70 employees, and is wholly owned by the Baud family, and is currently run by the brothers Christophe and Matthew. They originally started out making optical (corrective) lenses, but they evolved into sunglasses and action sports wear. In 1950 Julbo was the first company to produce true mountaineering glasses (the Vermont Round), so they have a rich history in high altitude optics.

Julbo Dirt
The Julbo Dirt is a bit of a departure from the average sports eyewear, and instead of the atypical thin or skinny frame, its built beefier, with a very wide section by the hinge and temple, which offers additional side protection from sunlight. The hinged wraparound frames have a nice sculptured curve, and has soft rubber shock absorbing material for the nose and ears, offering grip while doing athletic movement. They mainly come with the Zebra lens made from the indestructible NXT, which offer anti-fogging, impact resistance and light-sensitive Photochromic features. They also comes with a nifty hard case to carry, and protect them. The Dirt come in several versions and colors, the Zebra (NXT, Photochromic 2-4, Antifog) in White, Black, and Chocolate, the Camel (NXT, Polarized, Photochromic 3-4, Antifog) in Khaki and the Polarized 3 in black. If it’s required, you can order them with corrective lenses.

Measured Specs
Weight: 40 grams (1.4 ounces)
Lens size: 65mm x 40mm (2.5 x 1.5 inches)
Arm Length: 71mm (4 3/4 inches)
Frame Width: outer 145mm (5 3/4 inches) inner 130mm (5 1/8 inches)

Zebra Photochromic Lens
The Motions use Julbo’s Zebra photochromic lens made from the unbreakable, lightweight and very transparent NXT lenses. They quickly darken with a light brownish tint or lighten with an amber tint depending on light intensity, and have an anti-fog coating that has been laser etched into them. Per Julbo fodder “adapts to varying light conditions from Category 2 (59-percent visible light coverage) in low light conditions to Category 4 (95-percent visible light coverage) in powerful light in as little as 30 seconds”.

NXT Lens
The NXT polymer technology was born of the successful efforts to develop advanced transparent armor for U.S. Army helicopters. Commercial applications for the new transparent polymer material led to the production of lenses and shields for sunglasses and sport eye wear. The NXT lens is manufactured by pouring resin into a low-temperature glass molds. This reduces the tension in the material and gives better optical quality, excellent transparency and improved long-term stability. The NXT lens meets the ANSI Z87.1 standard for industrial application impacts, meaning it must withstand a pointed 17.6 ounce projectile dropped from a height of 50 inches, and 1/4 inch steel ball traveling at 150 ft/sec! I did not test either compliance, but I am glad it can take a wallop. Julbo lenses offer 100% protection against UVs: UVAs, UVBs, and UVCs.

For some in-depth fodder on Sun and Eyes, refer to http://mtbreviews.net/sunsunlight-101-and-human-eyes-101/

Impressions
What I really like about them is the full coverage they offer, giving good field of vision, aerodynamics and excellent wind coverage. I do hate eyewear that makes your eye water when you go ride into a strong headwind, or when you start to boogie going downhill. The Dirt offer incredible wind protection, almost like wearing a pair of goggles. I think the wind protection is due to the large lenses, wrap around frames, and that they sit close (but not to close) to your face.

Another per peeve is lenses that fog up on you, like when you go into a dense section of trees that might be humid, after a rainstorm, or when you start sweating, and then pop into a cold spot on the trail. The Dirt never seemed to fog on me in any of the adverse conditions that I dumped them into, so the anti-fog coating works amazingly well. The side sun coverage that the frame offers are quite nice, and cuts down on eye fatigue and scattered light entry, and the frame and lens curve around enough that the sides don’t interfere with your peripheral vision. The curve and shape of the frame, along with rubbery shock absorbing nose and ear coverings, keep the sunglasses stuck to my head no matter how rough the terrain tossed at me. They fit nicely within helmets, but bow out a bit much for a full faced helmet. With any pair of sunglasses, I can never decide whether to wear them under or over the helmet straps? They have been comfortable, with a nice fit and feel. One issue is there is no adjustability since the frame is not pliable (stiff frames) nor offers any adjustment features.

Thanks to the durable NXT, the lenses have been bombproof, and I have gotten no scratches, which is pretty amazing, since I always seem to do that with any eyewear, even the ones that are supposed to be unscratchable (marketing hyperbole). They have excellent varying light capabilities due to the Zebra photochromic lenses, and the amber tint has been especially nice on the cloudy and foggy days. Sometimes buzzing in and out of trees in the bright afternoon sunlight the lens did not change fast enough for those conditions, but it is a very minor issue. If I was doing a lot of desert riding, or was going to be constantly out in bright sunlight, I might prefer a somewhat darker lens. I usually ride in places in which I am going in and out of the shade, into wooded areas, and I also ride a lot in the late afternoon, so I appreciated the photochromic lens. The lenses have phenomenal optical quality, and they’re distortion free with a high degree of clarity. The lenses are large and curved enough for a nice panoramic field of view.

They also look fashionable enough to wear around the pool, hot springs or about town without looking like an outdoor sports geek or even a roadie! Ok, I still look like a geek?

Bottom Line
I really like the Julbo Dirt sunglasses, they are comfortable, stay put, have exceptional clarity, and offer excellent wind and side sun protection. The lenses’ photochromic capabilities are great in varying conditions, while the anti-fog actually works in real world conditions. The durable, scratch and impact resistant NXT material is pretty amazing, and offers outstanding safety. The Dirt is expensive (like a lot of the competition), the frames are a bit stiff, and do not offer any method of adjustment. Julbo has a winner with the Dirt, and they are ideal for mountain biking, having many of the functional features that work nicely for this niche.

Strengths
-Photochromic
-Scratch resistant
-Side sun protection
-Excellent wind protection
-Comfortable
-Superb Clarity
-Anti-Fog coating

Weaknesses
-Frames not adjustable
-Stiff frames
-Expensive

Overall Rating: 4 Flamin’ Chili Peppers

Dirt models:
Lens: Zebra – NXT + Photochromic 2-4 + Antifog
Color: White, Black and Chocolate
MSRP: $160.00

Lens: Polarized 3 / Lens
Color: Black
MSRP: $120.00

Lens: Camel – NXT + Polarized + Photochromic 3-4 + Antifog / Lens
Color: Khaki
MSRP: $190.00

Julbo Dirt url: http://www.julbousa.com/performance/dirt/

I have been doing some testing and reviewing of sunglasses lately, and I thought I would pass along some research I did while investigating sunlight and the human eye.

Sun/Sunlight 101
Our Sun, is a yellow dwarf, and specifically a G2V star, which means it’s a spectral type G2 (based on color and surface temp) and luminosity class V (based on surface area).

Surface temp: 5800 ºK or 9980 ºF
Core temp: 15.6 million ºK or 28.1 million ºF
Mass: 4.38 x 10^30 lbs.
Diameter: 864,000 miles
Age: 4.57 billion years
Composition: 74% Hydrogen/24% Helium/2% other
Color: White (appears yellow due to refraction)

The Sun generates its energy by nuclear fusion of hydrogen nuclei into helium, with a net output of 383 yottawatts (10^24). The Sun lays approximately 93 million miles from us, and its light travels that distance in 8 minutes and 19 seconds, which is about my average speed while mountain biking. Sunlight is the total spectrum of the electromagnetic radiation given off by the Sun, and its wavelengths vary from 100 nanometers to 1 millimeter, and are divided into five regions:

Ultraviolet C or UVC: spans 100 to 280 nm
Greatly absorbed by the atmosphere, it has germicidal properties, and is more powerful than UVA and UVB, but they can be fatal to an organism.

Ultraviolet B or UVB: spans 280 to 315 nm
Mostly absorbed by the atmosphere, overexposure can cause sunburn and some forms of skin cancer, and they cause irritation to the cornea.

Ultraviolet A or UVA: spans 315 to 400 nm
Less damaging to the DNA, but are responsible for premature aging of the eye.

Visible light: spans 400 to 700 nm.
It is this range that is visible to the naked eye, and it represents 45% of Sunlight.
Bright and intense light, can lead to fatigue, temporary reduction of sight, and eye pain over prolonged exposure, and even with brief exposure the retina may be damaged and suffer vision impairment.

Infrared light: spans 700 nm to 1 mm
It is largely responsible for the warmth or heat that the sunlight carries, and it represents 48% of Sunlight. They heat the tissues, dry out tears reducing their protective qualities and can cause eye disorders.

Human Eyes 101
The human eye is a significant human sense organ. It allows humans conscious light perception, vision, which includes color differentiation and the perception of depth. The human eye has a 200° viewing angle and can see 10 million colors.

Eye Parts
Cornea: transparent protective envelope, 300 times more sensitive to sunlight than the skin.
Iris: colored membrane surrounding the pupil, determines eye color.
Pupil: central part of the eye varying according to brightness.
Crystalline lens: a transparent positive lens which adapts itself to object distance, reflects light.
Vitreous body: gelatinous liquid located between the crystalline lens and the retina.
Retina: a plate which is hypersensitive to light, transmits information to the optic nerve and to the brain.
Optic nerve: it transforms the images perceived by the retina into nerve impulses.

The uvex Crow Pro sunglasses are an excellent performing set of eye wear, that come with 3 interchangeable one piece wraparound lenses, offering excellent peripheral vision, high quality optics, 100% UV protection and high-impact resistance.

Uvex
The uvex (pronounced ew-vex) brand was founded nearly 50 years ago in Fürth, Germany by the Winter family. The origin of the company name uvex (uv-ex = ultraviolet excluded), distinctly tells you that eye wear has been their preeminent product. Through the years, uvex evolved into two distinct entities, the sports division (ski, cycling and motorbike helmets and eye wear), and a safety division (protective eye wear, helmets, hearing and hand protection, safety footwear and work wear). Their Astrospec industrial safety glasses have sold more than 100 million pairs! This past June, Magura USA became the US distributor for uvex.

Impressions
The sunglasses are nicely sculptured, were very comfortable, and the soft rear ear pads were especially nice. The frames are very well made, and the strong hinges are very robust and well engineered. As always, you know that you have a piece of German engineering in your hands. The build quality, and the small attention to the little details really stands out in this well made pair of sunglasses. They come with a hard case, and nice extra large cloth bag. It always seems to me that bags for sunglasses are too small, and you are always having to persuade the sunglasses into them.

“Put Edwina … back-in-bowl!”

Interchangeable Lenses
I used the sunglasses extensively this last fall and early winter, and I highly appreciated having the interchangeable lenses. The three multi-conditioned lenses, each with their own functionality, blended well with the varying environments, and time of the day that I went riding.

When I was going to be out in the open or in constant bright light conditions, I used the dark gray lens, which they called Polavision Smoke, meaning a polarized gray. When I was going to be on trails in which the light would vary greatly, with lots of shade to sunlight type of conditions, the yellow lens was incredibly versatile and ideal. The yellow lens was called Radar Dégradé, which had a color gradient, tinted at the top and clearing towards the bottom. The typical wooded terrain that I frequent locally in Colorado, made the yellow lens my preferred color, especially in the fall, and they were also nice for flat light and fog. During those late afternoon, and early evening rides, it was nice to have the clear lens. When the darkness starts to creep up on you, it is paramount to be able to see the slight idiosyncrasies of the trail while still having eye protection.

Switching the lenses was a very easy process. To take the lens off, just pinch the nose piece with one hand, and pinch the frame opposite the nose piece, pull them apart and twist the lens/nose piece just slightly up.

Remove the detachable nose piece, and switch it to the other lens. Insert one hooked tab of the new lens into the frame’s slot, align all the tabs, then holding onto the lens and frame at that far end (opposite the inserted tab), do a gentle pull and twist, and it will pop right together. After a few practices, it becomes second nature.

Venting
I really liked the small vent holes, which they call Climazone venting. It really helped clear the lenses when you built up some perspiration, or dealt with humid conditions, especially after a rainstorm. If you just moved along slightly, the lens cleared up instantly. The venting was a very nice addition for those cooler days, or when you sweat like a pig. Ok, pigs don’t actually sweat, since they have no sweat glands, but its a cool idiomatic term anyway.

One thing that sort of bothered me on occasion, is that the sunglasses sort of sat too close to my face and eyes. I really noticed it up by my eye brows, and sometimes when you weren’t moving the lens would fog, since they sat so close. Just some slight nitpicking.

Makrolon
In 1953 Edmund Hillary and Tensing Norgay conquered Mount Everest, but over in the scientific world the chemist Dr. Hermann Schnell working for Bayer Labs in Uerdingen Germany, invented a new class of plastic called polycarbonates, and so doing, successfully synthesized Makrolon. Polycarbonates are a particular group of thermoplastic polymers. Polycarbonates received their name because they are polymers having functional groups linked together by carbonate groups (-O-(C=O)-O-) in a long molecular chain. In the last 50 years Makrolon has been used in a plethora of products, including eyeglasses, goggles, helmets, automotive glazing and headlights, sheeting for green houses, water containers, and the ubiquitous CD/DVD.

The Crow Pro, and all uvex sport glasses lenses are made of Makrolon, which provides high transparency, high impact-resistance and practical unbreakable. Uvex does a firing test using a 6mm steel ball traveling at 162 km/h (45 m/s), and the lens must not break or be penetrated. These lightweight and durable lenses, provide excellent optical quality, blue light filtering, and 100% UV400 (400 nanometers) absorption regardless of the lens color.

Each of the lenses I tested had a subtle mirror coating, called Lite Mirror, that offers protection against infrared light. The lenses are also protected with what they call Supravision, which is a nano technology that enables a scratch proof, and fog-free lens, along with 100% UV protection. All lenses are tested according to the stringent European standard number EN 1836.

For some in-depth fodder on Sun and Eyes, refer to http://reviews.mtbr.com/blog/sunsunlight-101-and-human-eyes-101/

Measured Spec
25.1 grams

I tested the Crow Pro Pola version, but they also come in a non polarized Crow Pro version. Check out their website for more in depth information regarding frame, and lens colors.

Bottomline
I really liked the uvex Crow Pro Pola sunglasses. The three interchangeable multi-conditioned lenses were of the utmost usefulness, and I especially liked having the yellow (my fave), and clear lenses. The German engineered glasses were very comfortable, well built and durable. The Makrolon lenses offered excellent optical and impact qualities, and the wraparound single lens had an expansive peripheral vision. Like any good sunglasses, they have 100% UV protection, which is paramount for good long term eye care. The Climazone air flow venting system is a nice feature to have, especially on cool or inclement days. The only fault I had was that they sat a bit to close to my face. Uvex has created a worthy pair of sunglasses with the Crow Pro.

Strengths
-3 lenses
-Comfortable frames
-Easy lens interchangeability
-Air vents
-Impact Resistance

Weaknesses
-Sits to close to the eyes and forehead

MSRP $80

Uxex Crow Pro Pola Website

Uvex Crow Pro Pola Specs
- Frame Color: Black and Gold, or White or Black
- Optically correct
- 26 grams
- 3 multi-condition lenses: Gray, Clear and Yellow
- hard case
- soft pouch/lens wipe
- uvex anti-allergic, ultra soft nose pads
- uvex Anti-allergic, soft temple ends
- UV 400, 100% UVA, UVB, UVC

Lens Specs

Litemirror Clear
* For use at night
* Protection against wind, insects, dust and infrared
* Transmission: 43-80%
* Protection level: S 1

Litemirror Radar Dégradé
* Contrast enhancement
* Infrared protection
* Transmission: 43-80%
* Protection level: S 1

Litemirror Polavision Smoke
* Makes a visible different. Irritating reflections and glare are filtered out.
* Sun protection throughout the day
* Natural colors, natural contrast
* Transmission: 8-18%
* Protection level: S 3