There are lots of people wasting a lot of time and money trying to pass one of a battery of tests designed to weed out those with any CVD. The 'problem is the test' and not the practicality of flying.
Here's my proposal to the UK CAA as a streamlined and much fairer methodology. Still a bit discriminatory but it sa start.
I'd like to see all the Farnsworths/HolmesWright/Nagels/Spectrolux lanterns taken to the dump where they belong. Their time as 'good little earners' for you medical guys should come to an end.
As primary testing use Ishihara plates which is fine as a go/nogo test to determine if someone has a deficiency.
Issue restrictions of no scheduled charter to those failing Ishihara and allow the restrictions to be lifted if the person can name the coloured lights shone from the control tower (once in 24 years of flying I had a light shined at me - my radio was broke - it was day VFR I could see the runway was clear anyway).
We are lucky in Australia/NZ that even if you fail the colour tests badly (like me) you can still do everything except fly scheduled airlines which leaves all the other more interesting stuff. I could try the tower lights and if pass try for the airlines but I am too old now to bother (45). I wasted too much time in the UK trying to make headway in their system.
15 years back I was simply dissallowed commercial full stop. Thats nice!
I hear now I can have commercial but no charter (unscheduled or scheduled)
NZ is much the same way as Oz but they still wont let you fly at night for some strange reason.
I'd love to see a matrix of country versus what you can do with a moderate/severe CVD. I can fill in the Oz/NZ part but not sure of UK.
Might help some real keen people prepared to migrate tosolve the problem. I did.
OOW CPL(A) CPL(H)