What is Defective Colour Vision?
Defects in colour vision, often incorrectly referred to as colour "blindness" fall into two main categories:
(a) Congenital Colour Vision Defects
(b) Acquired Colour Vision Defects
The distinction between the two varieties are that acquired defects are often the result of some disease process which affects the colour vision receptors or higher neural pathways. Congenital colour vision defects are genetically related.