Long nose fly mask. I had a horse who didn't have a lot of white - just a moderate width blaze/snip - but he had very fine summer hair and his blaze would burn right up to the bottom of his normal flymask. I'm sure he'd have burned up to his eyes without the mask. I used zinc ointment on him to soothe and protect.
Then I got him a long nose fly mask and WOW! did it make a huge difference for him. No more zinc ointment. The one I got wasn't as long as the Crusader, it ended about a finger's width above his nostrils, but it provided enough shade that his snip didn't burn. Some horses find the long Crusader annoying, but it's easy enough to make it a bit shorter if you find that's the case.
For my mare I use a long nose Cashel fly mask and then I slather her pink nose with a super high SPF ( I can't remember the strength) that is waterproof and made for children so it's for more sensitive skin. Since I board, I put it on her each night thickly and it lasts through the next day.
I use people sunscreen in the spray/mist-type bottle with my Ap. It is the easiest to apply, just spray, and my horse doesn't mind it. And it is relatively cheap. Plus my vet is the one who recommended it.
“Be yourself; everyone else is already taken.”
¯ Oscar Wilde