Some moments turn sport into a test of absolute focus.

For Katja von der Burg, those moments arrive when the trail gets loose, the descent gets faster, and the light becomes harsher. When the wind picks up and your eyes begin to water. That's where equipment either performs, or it doesn't.

"I realized during the Transalpine Run in 2016 just how inadequate my previous setup had been," Katja says. She has been wearing SIOLS ever since.

What SIOLS has changed most is her vision under pressure. Katja doesn't simply throw on any pair of sunglasses. Ultratrails, road cycling, alpine adventures, ski touring. Her world is outdoors, often for hours at a time and under constantly changing conditions. Add highly sensitive eyes, and clear vision becomes essential.

"In the mountains, I'm almost always wearing sunglasses, even on cloudy days," she explains. "There's nothing worse than flying down a technical descent and suddenly not being able to see because your eyes start watering."

Where speed meets precision, clear vision becomes a matter of safety.

One feature won her over from the very beginning: interchangeable lenses.

"They were brilliant for changing light conditions," Katja says.

Later, SIOLS Thermo lenses became her go-to choice for winter sports like cross-country skiing and ski touring.

"They're incredibly helpful because nothing fogs up or freezes."

Right now, however, it's the new FLITE.Rim Shields that have captured her attention.

"I'm in love with the new FLITE.Rim lenses."

Their latest test came on the roads of Mallorca. Strong winds. High speeds. The kind of conditions where many sports glasses begin to struggle.

"We had incredibly strong winds, but I got through the rides with perfectly clear vision and without my eyes watering.

For Katja, that's about far more than comfort.

"Besides the excellent fit, it's an important safety factor for me."

When the weather is unpredictable, she chooses the photochromic Vario lens. In winter, there's no debate.

"I swear by the Thermo lenses."

The true value of reliable vision became even clearer during the Haute Route, the legendary multi-day ski traverse from Chamonix to Zermatt.

Glacier altitude. Intense alpine sunlight. Wind. Cold. Long technical sections where every step matters.

"When I'm standing on a steep slope with crampons and an ice axe, I have to trust my equipment one hundred percent."

That was exactly where her SIOLS eyewear made the difference.

She carried ski goggles in her backpack, but barely needed them.

"I wore my Aero Thermo lens practically the entire week without taking it off once. It simply worked."

Sometimes, perhaps, a little too well.

"I've even caught myself looking for my sports glasses, only to realize they were already on my face."

It's a line that says everything about truly great equipment.

Because in the end, Katja doesn't want to think about her eyewear.

She wants to forget it's there.