night vision vs night-sight

night vision and night-sight both are nouns.

Word	Noun	Adjective	Verb	Adverb
night vision	Yes	No	No	No
night-sight	Yes	No	No	No

As nouns, night vision and night-sight are synonyms defined as:

night vision and night-sight: the ability to see in reduced illumination (as in moonlight)

Other synonyms of night vision include scotopic vision, twilight vision.

night vision (noun)	night-sight (noun)
the ability to see in reduced illumination (as in moonlight)	the ability to see in reduced illumination (as in moonlight)