aniseikonia vs visual defect

aniseikonia and visual defect both are nouns.

Word	Noun	Adjective	Verb	Adverb
aniseikonia	Yes	No	No	No
visual defect	Yes	No	No	No

As nouns, visual defect is a hypernym of aniseikonia; that is, visual defect is a word with a broader meaning than aniseikonia:

aniseikonia: visual defect in which the shape and size of an ocular image differ in the two eyes
visual defect: impairment of the sense of sight

Other hypernyms of aniseikonia include vision defect, visual disorder, visual impairment.

aniseikonia (noun)	visual defect (noun)
visual defect in which the shape and size of an ocular image differ in the two eyes	impairment of the sense of sight