"Close your eyes and follow me."
Translation:Zamknij oczy i idź za mną.
"Zamknać" takes accusative, so it is "oczy". But why is it "mam dwoje uczu"? The numbers rule being "if the number is 2,3,4 or every other that ends with 2,3,4 (except those that end with 12,13,14) you go with plural nominative and you decline both number and noun if it is required in the sentence".
"Mam dwoje oczu" :) It's a special case, it's a remnant of the dual number that was once a part of Polish (and several other languages, some of them still have it). Basically things that usually come in pairs would behave differently in terms of grammar. "dwoje" is the collective form of the numeral "dwa" and it always takes Genitive.