Benjamin Clayborne
Auror
By the way: shooting something in the eye blinds it in one eye—it does not kill it. The optic nerve is around 3mm in diameter (an eighth of an inch, way smaller than any arrowhead), and the skull is not meaningfully weaker behind it than anywhere else. If the shot isn't going to penetrate the cranium elsewhere, it won't do it through the eye, either. You'd have just as much luck trying to go through the nose or palate… and might actually have better luck going through the ear.
To be fair, dragons are usually significantly larger than humans; it's not hard to believe their optic foramen (the opening in the back of the optical orbit through which the optic nerve passes) might be big enough to admit an arrowhead. I doubt most readers would care, though.