Something tells me the African savanna was not made of tarmac. There's probably also a reason folks in the great plains of Asia developed different eye adaptations than those who lived in (more forested) Europe.
Bright light is uncomfortable for some evolutionary reason, it seems stupid to ignore.
Perhaps this works: when in a dense forest looking for nuts, don't wear sunglasses. Plus: make sure kids spend time outdoors (nice if it prevents myopia, but it's sane in any case).
As for sunscreen: no strong opinion on its chemical properties, but I just avoid long durations of sun exposure at latitutes and seasons that's an issue. And I wear a hat.
That said, when the above is insufficient, I'll take my chances with whatever is for sale, rather than macho through sunburn and skin cancer (my skin color evolved for high latitudes).
I also vaguely remember reading (as that seems to be enough basis to make a bold claim these days) that kids instinctively seek out shade during play.
