Thank you all!
They responded to me today. They say that the missing eye was an accident, he wasn't born with just one eye. And they told me that the missing eye, or better the vet fee caused by the accident was the reason why his previous owner surrendered him to the hamster care association that I'm in contact with; they didn't want to pay for it.
They also said that he wasn't born from a casual home breeding; I don't know what they mean by this, cause they can't tell me if he's a hybrid or a pure ww, I doubt the latter, and they have no information on the parents(I asked them if he was son of siblings).
But they assured me that he passed the medical check, and that he's healthy.
So in the end I did made the first step on adopting him today, and I have to thank you all for the support
