eyestrain vs asthenopia

eyestrain and asthenopia both are nouns.

Word	Noun	Adjective	Verb	Adverb
eyestrain	Yes	No	No	No
asthenopia	Yes	No	No	No

As nouns, eyestrain and asthenopia are synonyms defined as:

eyestrain and asthenopia: a tiredness of the eyes caused by prolonged close work by a person with an uncorrected vision problem

eyestrain (noun)	asthenopia (noun)
a tiredness of the eyes caused by prolonged close work by a person with an uncorrected vision problem	a tiredness of the eyes caused by prolonged close work by a person with an uncorrected vision problem