I had sudden hearing loss in one ear a few years ago. Off sick for a few months while I was tested for many causes that could have meant the end of my flying career.
Recovered a small bit of hearing, but well outside of standards in one ear. I currently wear an aid in the poor ear. This gets me to the maximum allowed db loss. Although, I still am required by my AME/company to complete a functional hearing test during my annual line check.
I know of an EU pilot that wears a Bone Anchored Hearing Aid (BAHA) on one side due to single sided hearing loss.
It can be done, but the only examples I know are for single sided hearing loss. I think that it would be difficult to enter the career with hearing issues. Keep in mind that the flight deck is noisy, so throughout a career one can expect further hearing loss. I religiously wear a custom ear plug in my good ear to keep what I have.