I can't give a definitive answer on this. What a few people have done in Australia is proven to CASA that they can operate safely with their vision defects.
A guy I know who is a "deutan" had a FAA IR and proved to CASA that he can operate safely because he had "x" number of hours doing just that.
Another friend who passed her class 1 vision standard years ago for CASA developed problems in her vision. She had been operating wide body jets. Her vision was corrected back to the standard with glasses and she was allowed to fly because she could prove that she had operated aircraft safely. She also managed to get that waiver from the CAA. On paper she shouldn't have because her eyes are now out of JAR tolerance.
In a nutshell, you have to be able to prove to the authority that your eyes aren't a problem in safely operating an aircraft. There's no guarantee that they will go in your favour but it has to be better than nothing.
The colour blind pilots in Australia have Dr Arthur Pape to thank. His tireless efforts changed the rules there.