ophthalmic vein vs vena

ophthalmic vein and vena both are nouns.

Word	Noun	Adjective	Verb	Adverb
ophthalmic vein	Yes	No	No	No
vena	Yes	No	No	No

As nouns, vena is a hypernym of ophthalmic vein; that is, vena is a word with a broader meaning than ophthalmic vein:

ophthalmic vein: either of two veins that serve the eye; empties into the cavernous sinus
vena: a blood vessel that carries blood from the capillaries toward the heart

Other hypernyms of ophthalmic vein include vein, venous blood vessel.

ophthalmic vein (noun)	vena (noun)
either of two veins that serve the eye; empties into the cavernous sinus	a blood vessel that carries blood from the capillaries toward the heart