Martin has severe myopia, with a far point of only 19cm . He wants to get glasses that he'll wear while using his computer, whose screen is 63cm away.

What refractive power will these glasses require?

And also please,

Mary, like many older people, has lost all ability to accommodate and can focus only on distant objects. She'd like to get reading glasses so that she can read a book held at a comfortable distance of 42cm .

What strength lenses, in diopters, does Mary need?

Answer rating: 100% (QA)

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