photoretinitis vs vision defect

photoretinitis and vision defect both are nouns.

Word	Noun	Adjective	Verb	Adverb
photoretinitis	Yes	No	No	No
vision defect	Yes	No	No	No

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

photoretinitis: damage to the retina resulting from exposure of the eye to the sun without adequate protection
vision defect: impairment of the sense of sight

Other hypernyms of photoretinitis include visual defect, visual disorder, visual impairment.

photoretinitis (noun)	vision defect (noun)
damage to the retina resulting from exposure of the eye to the sun without adequate protection	impairment of the sense of sight