"Bana gözlük al!"
Translation:Buy glasses for me!
Like how you can say "Buy me new glasses!" in English, I suppose.
It is the command form (imperative) of "almak" (to take, to receive, to buy).
But the Turkish does not use those English words you used; the Turkish uses Turkish words: Bana gözlük al!
almak can mean not only "to take" but also "to buy". So I would understand the sentence as "Buy me glasses!"
"gelasses" is not an English word; Duo was right to refuse it.