chronic glaucoma vs glaucoma

chronic glaucoma and glaucoma both are nouns.

Word	Noun	Adjective	Verb	Adverb
chronic glaucoma	Yes	No	No	No
glaucoma	Yes	No	No	No

As nouns, glaucoma is a hypernym of chronic glaucoma; that is, glaucoma is a word with a broader meaning than chronic glaucoma:

chronic glaucoma: glaucoma caused by blockage of the canal of Schlemm; produces gradual loss of peripheral vision
glaucoma: an eye disease that damages the optic nerve and impairs vision (sometimes progressing to blindness)

chronic glaucoma (noun)	glaucoma (noun)
glaucoma caused by blockage of the canal of Schlemm; produces gradual loss of peripheral vision	an eye disease that damages the optic nerve and impairs vision (sometimes progressing to blindness)