In message , DW
downunder writes

I understand the incidence of colour vision impairment is around 25% of
males and a low % of females, maybe 13% of the total population.

Do you have a citation for that? The figures quoted for all types of
colour blindness in most studies are 8% male and only 0.5% female - see
the Wiki article, which cites various studies to that effect.
--
Paul Terry