Colour vision deficiency and Visual impairment

Colour vision deficiency noun - Genetic inability to distinguish differences in hue.

Visual impairment and colour vision deficiency are semantically related. In some cases you can use "Visual impairment" instead a noun phrase "Colour vision deficiency".

Visual impairment noun - Impairment of the sense of sight.

Colour vision deficiency and visual impairment are semantically related. Sometimes you can replace phrase "Colour vision deficiency" with "Visual impairment", this phrases are similar.