Someone has stolen my spectacles. How many of 'THEM' actually?

Recently, my precious Prada spectacles were stolen.  What a bad sad experience! :( I'm still hoping to get them back.

Anyway, someone asked me 'How many spectacles have been stolen?' since I've used the word 'them'.
Only then I realised that he didn't know that 'spectacles' is a plural noun.
So, when I said 'them', I was actually refering to 'a pair of spectacles'.

They were also people who were confused when I used the word 'glasses' instead of 'spectacles' as they thought I had lost my drinking glasses.

Actually, 'spectacles' is rather formal. It is more usual to talk about my 'glasses' or 'specs'.