contact lens vs lens system

contact lens and lens system both are nouns.

Word	Noun	Adjective	Verb	Adverb
contact lens	Yes	No	No	No
lens system	Yes	No	No	No

As nouns, lens system is a hypernym of contact lens; that is, lens system is a word with a broader meaning than contact lens:

contact lens: a thin curved glass or plastic lens designed to fit over the cornea in order to correct vision or to deliver medication
lens system: a transparent optical device used to converge or diverge transmitted light and to form images

Other hypernyms of contact lens include lens, lense.

contact lens (noun)	lens system (noun)
a thin curved glass or plastic lens designed to fit over the cornea in order to correct vision or to deliver medication	a transparent optical device used to converge or diverge transmitted light and to form images