Ok. Here is more food for thought. I know cvd can't be cured at moment, but if a lense can be produced that corrects the defficiency to allow you to pass the ishihara test why can't it be used as an aid. Just as some pilots carry two lots of glasses or contact lenses around. I can see nearly all ishihara test plates a normal bulb lit room but not all in outdoor light......?????? so read this and see....!!!!!!!!
Correction of Colour blindness - colour vision deficiency test
If it worked,,,,,,why couldn't it be used as an aid ? god knows how many pilots need glasses as an aid. Some pilots I know can't even read instruments without glasses
Regards nigel