vena ophthalmica vs vena

vena ophthalmica and vena both are nouns.

Word	Noun	Adjective	Verb	Adverb
vena ophthalmica	Yes	No	No	No
vena	Yes	No	No	No

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

vena ophthalmica: 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 vena ophthalmica include vein, venous blood vessel.

vena ophthalmica (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