cataract vs eye disease

cataract and eye disease both are nouns.

Word	Noun	Adjective	Verb	Adverb
cataract	Yes	No	No	No
eye disease	Yes	No	No	No

As nouns, eye disease is a hypernym of cataract; that is, eye disease is a word with a broader meaning than cataract:

cataract: an eye disease that involves the clouding or opacification of the natural lens of the eye
eye disease: any disease of the eye

cataract (noun)	eye disease (noun)
a large waterfall; violent rush of water over a precipice	any disease of the eye
an eye disease that involves the clouding or opacification of the natural lens of the eye