monochromatic vision vs monochromasy

monochromatic vision and monochromasy both are nouns.

Word	Noun	Adjective	Verb	Adverb
monochromatic vision	Yes	No	No	No
monochromasy	Yes	No	No	No

As nouns, monochromatic vision and monochromasy are synonyms defined as:

monochromatic vision and monochromasy: complete color blindness; colors can be differentiated only on the basis of brightness

Other synonyms of monochromatic vision include monochromacy, monochromatism, monochromia.

monochromatic vision (noun)	monochromasy (noun)
complete color blindness; colors can be differentiated only on the basis of brightness	complete color blindness; colors can be differentiated only on the basis of brightness