What level of UV protection is recommended for glacier travel? For example, I have sunglasses which says 40% UV layer. Will this be ok for glacier trekking, or do I need glasses with higher level of protection?
Snow blindness is at best very painful. UV damage to your eyes is not something you want to play around with. If only 40% protection they are are not sunglasses, they are fashion accessories and offer no where near enough to protect your eyes for more than an hour.
For $10 you will get glasses that provide 99% protection, why risk it?