I'm indigenous in northern Ontario and in the winters, especially late winter and the start of spring when we have lots of sun and lots of snow everywhere, snow blindness is no joke.
I've had snow blindness three times as a stupid little kid. It's like having an uncontrollable itch behind your eyeballs. There's nothing you can do about it and you can't keep your eyes open either. The most comfortable thing to do is close your eyes and keep them closed until it gets better ... which is usually a day or two ..... which makes you literally blind during that whole time.
We live just north enough to deal with some risk to snow blindness but south enough that it isn't usually a problem for us. We live in the trees and forest so the light is always broken up even on the brightest days. The Inuit north of us have it worse, they live in the wide open unbroken snow and sun all winter long.
It isn't a problem unless you're a dumb kid that doesn't want to listen to his parents.