You mean a LAME then.
AME / LAME - easy mistake to make. Bl**dy acronyms!
As has been said, the Gold Standard of colourblindness is the Holmes Lantern test - I've heard of many people who can't pass Ishihara who have passed the lantern.
Optometrists do not to have the lantern test because it is a very expensive piece of kit so is limited to university research departments and the CAA.