How can I know if my Louis Vuitton sunglasses are authentic?

I bought Louis Vuitton sunglasses from Ebay and they were described as “Authentic Louis Vuitton” but since there are so many knock offs items there I’m not sure. Can anyone help me tell whether they are authentic or fake? They have the Louis Vuitton monogram on the sides of the earpieces and also say “Louis Vuitton” on the earpieces. On the front of the earpieces near the lense it has the “LV” design. Are they authentic? Thanks for your help.
I didn’t ask if I should have bought them off ebay or not, I’m asking if they are real. Don’t answer if you’re just going to waste my time…and no,