These guys do consulting for these sorts of issues, many professional pilots use them. They can probably address your chances of keeping your first class in the long run:
http://www.aviationmedicine.com
Unfortunately, I think you can expect trouble getting hired at most major airlines and some regionals.
Some majors and maybe one regional do an extensive medical exam as part of their interview. They normally apply HIGHER standards than the FAA (illegal in my opinion). My best guess is that you would not be able to get hired at one of these companies.
Other companies specify that you must have an FAA first class with no waivers...you would probably have difficulty here too.
Some companies may just want a first class...I would suggest looking on various airline web pages for their hiring requirements. If they do not require a waiver-free medical you may have a shot. However, even if they do not specifically require a waiver-free medical, they may evaluate waivers on a case-by-case basis.
This is a tricky issue, so I'm guesing without hard facts. The airlines DO NOT publicize their detailed policies (liability) so if anyone else can offer an informed opinion that would be great.