presbyopia vs farsightedness

presbyopia and farsightedness both are nouns.

Word	Noun	Adjective	Verb	Adverb
presbyopia	Yes	No	No	No
farsightedness	Yes	No	No	No

As nouns, presbyopia and farsightedness are synonyms defined as:

presbyopia and farsightedness: a reduced ability to focus on near objects caused by loss of elasticity of the crystalline lens after age 45

As nouns, farsightedness is a hypernym of presbyopia; that is, farsightedness is a word with a broader meaning than presbyopia:

presbyopia: a reduced ability to focus on near objects caused by loss of elasticity of the crystalline lens after age 45
farsightedness: abnormal condition in which vision for distant objects is better than for near objects

Other hypernyms of presbyopia include hypermetropia, hypermetropy, hyperopia, longsightedness.

presbyopia (noun)	farsightedness (noun)
a reduced ability to focus on near objects caused by loss of elasticity of the crystalline lens after age 45	seeing ahead; knowing in advance; foreseeing
	abnormal condition in which vision for distant objects is better than for near objects
	a reduced ability to focus on near objects caused by loss of elasticity of the crystalline lens after age 45