"treefroginometry" wrote in message ...

I had an eye test a few years ago (about 10), it confirmed that I'm
red/green colour blind. Which I don't understand as I CAN see red and green.

Color (or colour) blindness is a misnomer. What it really means is
that your eyes detect certain colors at different frequencies than the
other 85% of the population. It doesn't mean that you are "blind" to
certain colors. The usual test for color blindness is the Ishihara
test. That is the one with patterns of numbers hidden in colored dot
patterns. With your color frequency shift, you have trouble
determining the difference between certain shades of the same color.
Therefore, you cannot distinguish between the dots that form the
number pattern and the surrounding dots. Oddly enough, since color
blindness is a frequency shift, rather than an actual blindness, there
are specially designed dot patterns where you will be able to see the
number pattern, yet those with "normal" color vision cannot.

Many people who cannot pass the Ishihara (one of the more sensitive
tests) can pass alternate color tests, such as the Farnsworth Lantern
test. I cannot pass an Ishihara, but easily passed the FAA's light
signal test and received a "Statement of Demonstrated Abilility"
(SODA). This removes the color test requirements from my medical
examination.

I don't know what the procedures are in the U.K., but you may want
to check and see if there are any alternatives to the standard test.

John Galban=====N4BQ (PA28-180)