Further to Kate’s point, get a good pair of sunglasses and wear them! Seriously, I have sensitive eyes so I squint a lot in the sun, and I think wearing sunglasses all the time (and therefore never squinting) has saved me from crow’s feet, for a few extra years at least. I turn 40 this year and you can hardly see any lines around my eyes. Even if your eyes aren’t as sensitive as mine, everyone squints a bit in the sun.