This is a subject about which I know lots! Middle D wore glasses from a much younger age than 18 months and had them fixed with elastic round her head.
One good thing nowadays is that lots of children wear glasses and they are a real fashion item - so do not worry of she has to continue to wear them.
Here's a tip - make sure you have a spare pair all the time; and buy a specs repair kit so that you can do running repairs yourselves. We live in the middle of nowhere and I spent a very great deal of time trecking back and forth to town on the bus with two children and pushchairs etc. getting specs repaired - sometimes more than once a week!! - so insist on a spair pair and get used to doing some repairs yourselves - they will get broken, I promise you!
And they will get lost..... in the sea; in the middle of a field of long grass ("where are your glasses?" - "over there" - points to acre of knee high vegetation! - we never did find them!); in fact just about anywhere!
And they will take some battering - or should I say "buttering". My D was once buttering her bread (very messy) and buttered her glasses too and could not understand why she could not see where she was going!
A sense of humour is required, and it is very important to keep it light-hearted and not get annoyed when they go missing or whatever - if they become a bone of contention then the trouble will start! Make sure she knows that you all think she looks lovely in them; and point out any children in books who have them ("Oh look, X has smart glasses, just like you!"). Also, if any other family members wear specs, you can do matey conversations about them, and clean them together etc. - I am a specs wearer and we used to have a sort of matey conspiracy going.
