Lex, first off, many thanks for writing. My gear lair was feeling lonely (Hint: the button to your left!). I don't think anyone makes better sunglasses for high-altitude climbing and snow activities than Julbo. The company has been around for 120 years, and while they have some other sport-specific and lifestyle offerings, they have definitely remained true to their strong mountaineering heritage. Julbos have proven sturdy, provide great coverage, and their lenses are exceptional based on the many pair we have tested at Outside. Julbo guarantees that all of their lenses offer 100% protection from UVA, B, and C rays, so you are covered with your first requirement. For your other must-haves, I asked Julbo CEO Nick Yardley specifically what lenses and frames you should get within the line.
The key thing to look for in a high-altitude snow lens is that it has a category four rating—which means it will block approximately 90% of visible light, Yardley says. Lens categories measure the level of darkness: zero is totally clear and four is the darkest you can buy. Most everyday-use sunglasses are category three, which block approximately 81-87% of visible light. This is great for driving and walking around on a bright day, but you need category four lenses when you are dealing with the brightness of snow and ice all day at altitude.
The type of category four lense you should buy depends on a few factors, one being eye color. "Someone with blue eyes is generally more sensitive [to light] than someone with brown eyes," says Yardley. Julbo's Spectron Four lens is their darkest, and will be your best bet if your eyes are really sensitive to light. On top of being damned dark, the Spectron Fours have an anti-reflective coating inside the lens in case any light sneaks in. These lenses are not polarized, but Yardley says that that polarization is not always ideal for high-altitude winter activities. "Polarization removes glare from surfaces, which is great for a fisherman, but can make it difficult to differentiate snow from ice," he says.
If you are looking for something a little more versatile and polarized, Julbo's Camel transition lenses are an excellent choice. They range from a category two to a category four lens depending on conditions, approximately blocking 78%-93% of visible light. Though Julbo does not recommend them for driving, they are great for many other everyday uses.
You should base your frame choice on two main factors, activity, and how much you want to look like a character from a Mad Max movie. I have a pair of Explorers and could care less about what they look like on a mountain—but when they were all I could find in my car in a drive from Santa Fe, New Mexico, to Los Angeles, California, I got some weird looks in rush-hour LA traffic. For a slightly less rugged looking frame, Yardley suggests the MonteRosa ($90-$190) for women and the MonteBianco ($90-$190) for men. They are lightweight and are easy to wear with or without a helmet. Check out the Trek ($120-$200) frames for more crossover use. Yardley says they vent extremely well and users love them as a mountain-biking and ultra-running frame, on top of using them for high-altitude climbing and snow sports.
So there you have it, Lex, almost 550 words on a single sunglasses suggestion. If you, or any other person reading this, have any gear questions, please submit them using the button in the lefthand margin, and I will try to research your question as exhaustively as this one.