The RAF uses the Holmes-Wright Type B Lantern Test for secondary testing.
If you are unable to see any of the Ishihara plates I would not expect that you would pass any of the secondary tests.
I would also be a tad concerned as some are designed to be visible to colour deficient persons, although with some numbers appearing more prominent than others, to determine whether you are protonomalous or deuteronomalous.
Also, if you cannot see the first plate there is a very serious problem as everyone should be able to read that, unless you do suffer with a form of numerical 'blindness' - the test has tracing and shape cards for persons who cannot read numbers.
Last edited by 2close; 17th Jun 2013 at 13:51.