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You're going to spend a lot of time looking up at your kite (and at the sun too) so UVA protection sunglasses are a must. The other thing is they offer you is protection against any slow moving bees and wasps you might clatter into. Congratulations, you are soon to become a human radiator grill.
Seriously, there are dozens and dozens of glasses and manufacturers out there but the key thing to look for are shatterproof lenses (for the obvious reasons).
If you can get a pair with a twisty frame that doesn't snap so much the better. Snow goggles are great but sometimes have problems with misting up.