eye vs OD

eye and OD both are nouns.

Word	Noun	Adjective	Verb	Adverb
eye	Yes	No	Yes	No
OD	Yes	No	No	No

As nouns, OD is a hyponym of eye; that is, OD is a word with a more specific, narrower meaning than eye:

eye (noun)	OD (noun)
a small hole or loop (as in a needle)	the right eye
the organ of sight	a doctor's degree in optometry
good discernment (either visually or as if visually)
attention to what is seen
an area that is approximately central within some larger region

eye (verb)	OD (verb)
look at