colour blindness vs color blindness

colour blindness and color blindness both are nouns.

Word	Noun	Adjective	Verb	Adverb
colour blindness	Yes	No	No	No
color blindness	Yes	No	No	No

As nouns, colour blindness and color blindness are synonyms defined as:

colour blindness and color blindness: genetic inability to distinguish differences in hue

Other synonyms of colour blindness include color vision deficiency, colour vision deficiency.

colour blindness (noun)	color blindness (noun)
genetic inability to distinguish differences in hue	genetic inability to distinguish differences in hue