I don't put sunscreen above my eyes either for the same reason - and I second the chapstick arc idea to redirect the sweat. If you really need the sunscreen there, you could get some of the baby no tears kind of sunscreen or sunscreen stick. It might be too thick for the rest of your face, but you could use it just on your forehead.

Even without sunscreen, just sweat running into my eyes stings. My buff usually does the trick, but the chapstick trick helps.