Zamfire,
I've successfully gone through the process.
My eyesight is 6/6 (20/20) in my left and 6/9 (20/30) in my right and with both eyes together it is obviously 6/6 (20/20).
I originaly travelled to the USA (2003) to gain an FAA IR and pass a PPL checkride to obtain a full standalone-not-based-on-any-foreign-licence FAA PPL/IR. However because I had around four hundred hours at this point the IR examiner talked me into doing an FAA CPL checkride instead which I passed. When this all happened I had only an FAA Class 3 medical as I thought I wouldn't be able to hold any higher medical due to my right eye correction (the FAA stipulates 20/20 in each eye seperately for Class 1 and 2 medicals).
So I then held an FAA CPL/IR with an FAA Class 3 medical. In FAA land one can obtain any level of certificate up to FAA ATP with just an FAA Class 3 medical. However, obvious as it may be, one cannot use the privilages of the certificate unless you have the appropriate medical. So I was limited to private flying only with my FAA CPL/IR and FAA Class 3 medical (which was all I wanted it for anyway).
At my medical renewal a couple of years later my FAA AME asked if I wanted to go and try to obtain an FAA Class 1 medical. We had a discussion and it transpired that he would do the medical examination and if I otherwise passed (except the right eye being 20/30) he wouldn't be able to issue the certificate but would pass all of my information to Oklahoma FAA medical division for a decision.
I did have to have an FAA opthamology report filled in by the optician and had numerous tests done there. These were faxed off to the FAA via my AME.
A couple of weeks later I received through the post a letter from the FAA. I thought it was going to be a denial of medical certificate or more probably an FAA Class 3 medical.
However when I opened the letter I found inside an FAA Class 1 medical with the limitation "Must wear corrective specs" and "Not valid for any class after November 2005".
The accompany letter said I was issued an FAA Class 1 medical under special issuance. The condition of the issuance was that I furnished an opthamology report at least yearly. So at the second renewal (Class 1's are valid for 6 months and I wanted to keep the Class 1 medical valid even though I could have let it lapse to Class 2 privilages) the medical said "Not valid for any class after November 2006" and so forth...
It appears the FAA takes each case on its own merits and can issue medicals under special issuance if one furnishes the required information and it is acceptable by the medical division. Basically they want to ensure you're not going to be a risk to other people, whether flying with you or on the ground.
I did have about 500 hours and an FAA CPL/IR before applying for an FAA Class 1 medical. However I don't think they took any of this into the equation and I believe it was purely based on opthamology reports etc. I would not recommend getting a certificate without getting the medical first if you are wanting this purely for a career.
All the best!