cystoid macular edema vs oedema

cystoid macular edema and oedema both are nouns.

Word	Noun	Adjective	Verb	Adverb
cystoid macular edema	Yes	No	No	No
oedema	Yes	No	No	No

As nouns, oedema is a hypernym of cystoid macular edema; that is, oedema is a word with a broader meaning than cystoid macular edema:

cystoid macular edema: a specific pattern of swelling in the central retina
oedema: swelling from excessive accumulation of watery fluid in cells, tissues, or serous cavities

Other hypernyms of cystoid macular edema include eye disease, dropsy, edema, hydrops.

cystoid macular edema (noun)	oedema (noun)
a specific pattern of swelling in the central retina	swelling from excessive accumulation of watery fluid in cells, tissues, or serous cavities