The symptoms of more serious inherited colour vision problems and some types acquired problems may include:
Nystagmus
The most severe form of colour blindness is achromatopsia. A person with this rare condition cannot see any colour. Achromatopsia is often associated with lazy eye, nystagmus (small, jerky eye movements), severe light sensitivity, and extremely poor vision.
Detection and Diagnosis
Colour vision deficiency is most commonly detected with special coloured charts called the Ishihara Test Plates. On each plate is a number composed of coloured dots. While holding the chart under good lighting, the patient is asked to identify the number. Once the colour defect is identified, more detailed colour vision tests may be performed.
Another interesting colour blindness test is below
The test to the left is simpler.
The individual with normal colour vision will see a 5 revealed in the dot pattern.
An individual with Red/Green (the most common) colour blindness will see a 2 revealed in the dots.
Source:http://en.wikipedia.org/wiki/Colorblind#Causes / http://www.toledo-bend.com/colorblind/ishihara.html