Colour vision deficiency and Monochromasy

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

Monochromasy and colour vision deficiency are semantically related. In some cases you can replace term "Monochromasy" with "Colour vision deficiency", this terms are similar.

Monochromasy noun - Complete color blindness; colors can be differentiated only on the basis of brightness.

Colour vision deficiency and monochromasy are semantically related. You can use "Colour vision deficiency" instead a noun "Monochromasy".