Latest situation
Hi all,
Sorry if I'm repeating what others have said earlier but my CAA JAR class 1 experience went like this (yesterday!).
After making 2 errors on the Ishihara (which I think I was given the opportunity to fix) we went to the Lantern test, which I also failed - possibly up to 4 times.
I was then given the opportunity to do the test again in the dark and was given 10 minutes to 'dark-adjust'. No problems thereafter (but a bloody nerve wracking 10 minutes sitting in the dark pondering the imminent demise of my not-yet-started aviation career!).
I asked the guy about it afterwards. Under JAR any mistakes on Ishihara require the lantern test - whereas in Oz I believe you're allowed a mistake or two (not certain on this - but I'm fairly sure I always make at least one mistake on the Ishishara).
He also said that colour blindness is NORMALLY congenetive and that once he'd checked that it wasn't related to a problem with my eyes (i.e. they were healthy) there would be no more testing without some kind of trigger reason. He did say that certain prescription medicines have the ability to affect colour perception and so reporting being on one of those would require a retest.
Hope this helps,
UTR.