The Isihara test is a load of crap. You can have perfect real life CV and fail it almost totally.
Totally agree! Ok if you are going for a job reading numbers from a book there maybe some relevance in this test.
I have had a fraction of CB since I started flying over 20 years ago. Never enough to warrant further tests or restrictions through several AMEs.
Lo and behold I was told I needed minimal glasses for reading. Off to the eye specialists who told me they could give me prescription glasses but did I really need them. Ok AME is King so I had them but being bashful and not wanting to wear glasses I asked them to colour them so they looked like light sunglasses.
Back to the AME who insisted on the whole eye test wearing the prescription glasses.
I could hardly get a page right. I argued that how could this be as CB doesnt change? Then it dawned on me. Look at yellow through blue glasses and you will see green. Look at Dots through brown lenses and what will you see with perfect colour vision.
I argued to do the test without the glasses but NO GO! okay ban all pilots from using sunglasses as they would all fail this stupid test.
Had to go away yet again and at vast expense have some new glasses made in clear glass.
Pace