Warning: If you are allergic to Visine, don't put it in your eye.
How will you know, you ask? Ah, funny thing about that--you can't know until you've already put it in your eye.
But don't worry. It's only a scratchy, burning sensation and lids swollen like you've been crying for hours (with one eye).
Take it from me, ol' Puffyface McRedEyedWetzel, who found this out last night and still looks like she was punched in the face.