This article is from the Vision and Eye Care FAQ, by grants@research.canon.com.au (Grant Sayer) with numerous contributions by others.
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.
 
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