M.O.
This is probably a ridiculous answer, but medically, does she absolutely need glasses, at such a young age? If you wait even a few more months, she may enjoy the contrast between blurry and clear, and she'll be able to see -- literally -- the advantages of being able to see. But an 18-month-old, neurologically, is a super-mobile, super-dexterous, (and super-cute) infant. And there's nothing they love more in the world than removing things -- hats, mittens, socks, all clothes, other people's glasses, let alone their own glasses. I'm just not sure this is a winnable battle, at this age.