Im thinking about buying some AO GENERAL SUNGLASSES but I dont know my size, However the 55mm rayban

[Ek70R]

Okey I live in Nicaragua so not many people knows about AO sunglasses, only raybans, I dont want to buy a 400 dollars sunglasses, thats why I decided to buy AO, because of their higher quality-price ratio. The other day I went to a optic in my city, tested raybans and saw that the 55mm fitted perfect on my face, I want to buy AO generals which dont come in 55mm sizes, so I dont know what to do, since I dont live in EEUU I cannot simply buy a pair and resend it to the dealer if it dont fit or go to a store ask for AO aviators and see which one fits best. Anyone Help here pliz? it is my first post ever here. Thank you guys