Sebastian - If I read your post correctly you mention a refractive error of minus 12. This is a very large error and while the FAA do not specify a pre correction limit you might want to consult an opthalmologist to find out what is likely to happen to your vision as you grow older.
Whether an airline will discriminate against you because of your myopia is anyone's guess..........In theory they should not, but this is the real world and individual airlines will adopt certain criteria for selection as a matter of course.
Surgical correction is an option but you should discuss the impact on your medical with an FAA AME. Implants I believe are frowned upon whereas laser correction is becoming routine and is not disqualifying. However if you are truly minus 12 then I think you are outside the limits for the laser procedure.
You might also want to consider your chances of getting a visa to work in the US. They are few and far between.
In summary you have plenty of time so carry out some intensive research then examine your findings in a very critical light.