I Took REACTIV Lenses for Granted — Until I Forgot Them

REACTIV lenses change according to light intensity. Full sun- they go dark. Move into the shadows- they quickly transition to allow more light. Back to sun-dark. Clouds block the sun-right back to light. For mountain athletes, trail runners, cyclists, and ski tourers, the usefulness of this technology cannot be overstated. For use on snow, the functionality might be even more critical if there is movement in and out of full sun. In that situation, a dark, fixed lens and a pupil adjusted for high brightness will be unable to see much of anything when moving into shadows.

 Quick transitions between sun and shade are something to consider.  Julbo claims to have the fastest adjusting lenses. While I can’t confirm that (not having tested all the others), I can witness the time it takes the lenses to adjust by putting a pair of glasses in the sun with something covering half the lens. Within seconds you’ll have a lens with a distinct line separating a mirrored lens and a clear lens.

 Aother advantage of REACTIV lenses is that they allow you to peer into the depths of a dark backpack interior on a bright, sunny day. This sounds minor but it can be really annoying on a bright day – you pull off your pack to root around for whatever and you can’t see a thing with your glasses on. I have actually recognized that REACTIV lenses transition enough to let you see into darkness then boom, right back to dark.

Optically, Julbo’s lenses are the highest quality allowing your eyes and brain to focus on the terrain rather than making dizzying adjustments due to distortion. Mountain athletes spend a lot of time studying the world with glasses on, so good ones help avoid headaches and confusing sight issues.

Julbo offers a variety of REACTIV lenses for different needs. Nail the right lens for what you do most and you’ll likely
only have to own one pair of sunglasses. (Although I will also suggest multiple if you go to high elevation, glaciers, or ski tour.)

 REACTIV 0-3 / 0-4: 0 is the least dark lens, perfect for low light days or even complete darkness when you still need a lens protecting your eyes (bugs, snow, dust, wind, etc…) 3 seems to be dark enough for most situations. I spend a lot of time running in California’s Sierra Nevada, famous for harsh sun, and 3 is plenty. But, if I know I’ll be on snow for extended periods, I will seek the cat 4 option. Imagine being able to go from pre-dawn headlamp use to 14,000 feet on a sunny, summer day, all with your sunglasses on. Your eyes will appreciate the care.

REACTIV 1-3 : This is the standard lens we use 90% of the time.

REACTIV 2-4 : Made for use in the brightest conditions on snow, glacier, high elevation, or even water.

REACTIV lenses are available with additional features:

Polarized : Primarily used on water, Polarized lenses also work well on glaciers and/or snow when there is a harsh reflection. Polarized lenses reduce or even eliminate reflections, saving your eyes from getting fried. 

Light Amplifier: Kim’s favorite, the Light Amplifier does just that, creating sharper, more contrasty vision in low light situations, but also a standard protection when the sunlight returns.

High Contrast : Made for continually changing conditions when you move in and out of different light, giving your eyes detail on both ends of the spectrum to identify obstacles.

Once you settle on the lens you feel is going to work best for your needs, the right fit is the next step. For trail running and mountain use, consider:

● Ultralight: less weight = less bounce, less of a nose beating, and less is typically best.

● You do not want glasses that slide off your sweaty nose, or that pivot up and down as you bounce down hill. Find a snug fitting frame but without too much pinch on the nose.

● A snug fit not just on your face, but also when perched on top of your head.

● You do not want a lens that is in contact with your brow or you’ll also need windshield wipers installed for
sweaty days.

● Wrap around shape or side shields to avoid sunlight hitting the backs of the lens when you are back or side lit.